resolve_relative_location removed "." and ".." segments only from a relative-path Location. A Location that starts with "/" or an absolute URI was requested as is, so a redirect to /dir/../target went out as /dir/../target and a server that does not normalize the path answered 404.
RFC 3986 section 5.2.2 applies remove_dot_segments to the target path of every reference that has a path, and Go and urllib3 do the same. The loop now lives in detail::remove_dot_segments, and ClientImpl::redirect applies it to an absolute path as well. Relative locations resolve as before.
On NTFS a ':' in a path names a stream of the file, so /dir/test.html::$DATA opened the default stream of dir/test.html and passed a set_pre_routing_handler() guard on /dir/test.html, and /setup.exe:Zone.Identifier served the stream Windows attaches to downloaded files. is_valid_path() now refuses a ':' on Windows.
Elsewhere a ':' is an ordinary file name character, so it is still served: a file such as 2024-01-01T10:00:00.log would otherwise answer 404. The test pins both sides.
last_event_id() returned a reference to a string that run_event_loop() assigns on its own thread under start_async(), so a caller reading it from another thread raced the writes. The member is now guarded by a mutex and the getter returns a copy.
The return type changes from const std::string & to std::string. Code that binds the result to a const reference or copies it still compiles.
write_websocket_frame and the request-body write in open_stream_ called
Stream::write once and only failed on a negative return, so a short
write (one record per mbedtls_ssl_write call, or SO_SNDTIMEO expiring
after part of the data went out) dropped the rest of the frame or body.
Route both through write_data, as the other body writers do.
Co-authored-by: yhirose <yuji.hirose.bug@gmail.com>
The macOS system CA loader took every certificate that has Trust Settings, in the system, admin or user domain, as a trusted root without reading those settings. A root set to "Never Trust" in Keychain Access, or trusted only for S/MIME or code signing, still verified TLS servers.
The loader now evaluates the settings for the SSL policy. A per-user setting overrides the admin domain, which overrides the system domain, and only TrustRoot and TrustAsRoot are loaded. The OpenSSL path shares the helper that the Mbed TLS and wolfSSL paths already use.
open_stream_() created a decoder whatever set_decompress() said, so a response stream decoded the body when decompression was disabled, and failed with UnsupportedContentEncoding in a build without that decoder. The buffered path already checks the option; the streaming path now does too. The new test covers open_stream() and stream::Get().
Fixes#2639.
OpenSSL 4.1 no longer falls back to the subject Common Name when it
checks a host name (RFC 9525), so SSLClientServerTest.TlsVerifyHostname
began failing in the Windows CI job that installs the newest OpenSSL 4.x.
Make every backend agree instead of following whichever OpenSSL is
installed. OpenSSL passes X509_CHECK_FLAG_NEVER_CHECK_SUBJECT to both the
handshake check and verify_hostname(), and Mbed TLS and wolfSSL drop their
own CN fallback. A certificate that names its host only in the CN is now
rejected on all backends, as it already was on BoringSSL.
is_redirect treated any 3xx with a Location as a redirect, so with set_follow_location(true) a 304 or 305 that carried a Location was followed. Only 301, 302, 303, 307 and 308 are redirects a client follows (RFC 9110 section 15.4), as in Go, requests and urllib3. A Location is still required. The 304 check in process_request that is_redirect now covers is dropped.
Without keep-alive, the client sends "Connection: close", but before
following a redirect it disconnected only when the response repeated
the option. RFC 9112 (section 9.6) lets a server close the connection
without repeating it, and a client that sent "close" must not send
another request on that connection. The redirected request was written
to the closing connection and failed with "Failed to read connection"
whenever the server closed it first. The client now disconnects before
a redirect or an auth retry whenever the request asked for the close.
Co-authored-by: Wleeaf <179125857+wleeaf@users.noreply.github.com>
apt on the runner mirror sometimes crawls for minutes
(actions/runner-images#14823), and the cross compiler is large enough
that its install alone used up the job's 10-minute limit. Loosen the job
limit to 30 minutes and limit the build step, which normally takes a few
seconds, to 2 minutes.
apt on the runner mirror sometimes crawls for minutes
(actions/runner-images#14823), which used up the job's 5-minute limit
before the test finished. Loosen the job limit to 15 minutes and limit
the test step, which normally takes about 80s, to 3 minutes.
In absolute-form the path follows the authority, so a path such as "@evil.example/x" made the proxy connect to another host and forward the origin's credentials. Both handle_request and open_stream_ now refuse such a path before anything is written.
Windows trims a trailing '.' or space from a file name, so a mount
point there served a file under a path other than the one a pre-routing
handler checked. A mount point now serves no path with a segment
ending in '.' or a space, on every platform; "." and ".." are among
them. The README no longer lists such names among the ones the file
system can still alias.
After answering, with a status below 400, a request whose body the
handler left unread, the server read past the body to reuse the
connection up to the payload limit (100MB by default), with only each
read bounded by the read timeout, so a slow sender could hold a worker
for a long time. It now skips at most
CPPHTTPLIB_UNREAD_PAYLOAD_MAX_LENGTH (256KB, as Go's net/http does)
within the read timeout as a whole, and closes the connection
otherwise. An error response already closed the connection.
set_file_extension_and_mimetype_mapping() kept the extension as given,
and a file's extension was looked up as it was, then in lowercase, so a
mapping given as ".pdf" never matched and one given as "PDF" matched
only files ending in ".PDF". The extension is now lowercased and loses
a leading '.' when it is set, as Apache's AddType does, and a file's
extension is looked up in lowercase only.
An exception handler that set no status sent its response with 200, or
with whatever status the throwing handler had set. The status is now
set to 500 before the exception handler runs, as ASP.NET Core does, so
it stays 500 unless the exception handler sets another one.
On a WebSocket upgrade, an exception from the pre-routing handler, the
pre-request handler or the sub-protocol selector skipped the exception
handler and dropped the connection without a response. Everything
before the protocol switches now goes through the same exception
handling as routing, so it is answered over HTTP. The WebSocket handler
itself still runs outside it.
The test was kept off Windows while reading the body of such a request
waited on the socket and could hang there. That wait was made
non-blocking soon after, and such a request no longer has its body
read at all, so nothing in it is specific to the platform any more.
A request with neither Content-Length nor chunked Transfer-Encoding
has no body (RFC 9112 6.3), and builds with TLS support read none.
Builds without it still read whatever followed such a request on a
connection about to close, up to EOF, as its body. Every build now
reads no body. Tests that exercised only that read, or passed whatever
the server did, are removed, and a new one checks in every build that
the bytes after such a request are not taken as its body.
A request whose Transfer-Encoding ended in chunked but listed more
(another coding before chunked, or chunked twice) was read with only
the chunked framing removed, so the handler got a body still in the
other coding. RFC 9112 6.1 lets a server answer 501 to a transfer
coding it does not implement. The server now accepts only a single
Transfer-Encoding field whose value is chunked, as Go and nginx do,
and answers any other list ending in chunked with 501 and closes the
connection. A list whose final coding is not chunked still gets 400.
RFC 9110 14.2 defines range handling only for GET, and a server must
ignore a Range header on any other method. The server parsed it on
every method, so a POST with a Range got a 206 slice of the handler's
response, or a 416 when the Range was malformed. Range is now parsed
only for GET and HEAD; other methods get the whole response, and a
handler can still read the header itself.
set_trusted_proxies() compared addresses as strings, so a proxy listed
as 10.0.0.2 was not trusted when a server listening on both IPv4 and
IPv6 saw it as ::ffff:10.0.0.2, and two spellings of one IPv6 address
did not match either. The listed addresses are now put in one spelling
when they are set, and so are the connection peer and each
X-Forwarded-For hop before they are looked up; an IPv4-mapped IPv6
address becomes its IPv4 address. The README now documents the setter.
The README said a redirect keeps the TLS verification settings. They
pass only from one HTTPS hop to the next; an HTTPS hop after a plain
HTTP one starts over with the defaults.
RejectsChunkOverheadPastItsLimit sent about 78 KB per case, and the
server refused the request a few chunks in and closed the connection
while the client was still writing, so the send failed now and then
instead of returning the 400. Pad each size line with a sixteenth of
the limit, so each request is about 10 KB and goes past the limit only
at its last chunks.
TLS settings take effect as a connection is set up, so after a client
changed one (server certificate or host name verification, a CA store,
a verifier) a later request still went over the connection kept alive
under the old settings, unverified if verification had just been turned
on. Each such setter now bumps a version that the connection records
when it is set up, and a connection set up under an older version is
closed instead of reused. The setters take no lock, so they cannot wait
on a handshake in flight.
A server built with compression support compressed every handler
response the client accepted, with no way to turn it off. Over HTTPS
the length of a compressed response can give away a secret in it when
the same response also carries text an attacker chooses (BREACH).
set_compress(false) sends handler responses, buffered or streamed, as
they are; compression stays on by default, and static file compression
keeps its own setting. The README and the cookbook describe the switch
and when to use it.
tls::create_ca_store() on Mbed TLS parsed the caller's buffer with one
byte more than its length, so it read past the end of the buffer, and
when that byte was not a NUL the PEM was not recognized and the call
returned NULL. Parse a NUL-terminated copy instead, as load_ca_pem()
does. DER input still parses, since its own length ends it.
The server left response header fields with an invalid name or value,
such as a value carrying CR/LF that would split the response, for the
default header writer to skip, so a writer set with set_header_writer()
wrote them. Drop such fields from res.headers right after the handlers
that can fill it directly have run, before the server reads it for
framing and range decisions and before any header writer sees it. The
client already rejects invalid request headers before writing them.
The payload limit counts only chunk data, and a chunk-size line is only
bounded by the line length limit, so a peer could send a few bytes of
data with any amount of padding, leading zeros and chunk extensions
around them. Count those bytes as Go does: each chunk may spend 16
bytes plus twice its data on its size line and the CRLF after it, which
still lets a stream send a byte at a time, and the excess may build up
to CPPHTTPLIB_HEADER_MAX_LENGTH before the read fails. This covers
request bodies on the server and response bodies on the client.
The OpenSSL client finished the handshake with SSL_VERIFY_NONE and
checked the server certificate only afterwards, so it presented its
client certificate to a server that then failed verification. With a
server certificate verifier that accepted, wolfSSL did the same. Verify
the chain, and the host name, during the handshake on every backend,
keeping the built-in verdict when a verifier runs alongside it. On
OpenSSL a session verifier, which may accept a certificate the built-in
check rejects, still decides after the handshake.
A certificate that fails the built-in verification now reports
CertVerifyFailed, or HostnameMismatch for its name, in ssl_error() on
every backend, where OpenSSL left it 0.
tls::create_ca_store() parses certificates, which on Mbed TLS 4.x needs
PSA Crypto. A context readies it when it is created, but a store can be
made before any context exists, and then a valid PEM failed to parse
and the call returned NULL. Ready PSA Crypto first, as the contexts do.
Under the default system CA policy, a custom CA given to a client keeps
the system CAs out. SSLClient and WebSocketClient only noted the custom
CA when set_ca_cert_store() got a store or load_ca_cert_store() got some
bytes, so a NULL store, such as the one tls::create_ca_store() returns
for a PEM it cannot parse, or an empty PEM left the client trusting
every system CA instead. Note the custom CA on every call, so that such
a client fails verification. A redirect still passes a CA on only when
the original client had one.
A mount point left ".", ".." and empty path segments for the file
system to resolve, while the pre-routing handler, where the README has
applications guard static files, saw the path as it was sent. A file
could then be reached under a spelling that a check on req.path did not
match. Serve a path from a mount point only when it has none of those
segments other than a trailing '/', so that the file served is the one
req.path names; any other path now gets 404. The README also notes the
other names a file system can give a file.
SSLServer::update_certs_pem() loaded the client CA it was given but
left client certificate verification as it was, so on a server built
without a client CA it returned true while clients without a
certificate still got in. Turn verification on, as the constructors do
when they are given a client CA. A client CA passed to
update_certs_pem() now always makes client certificates required.
The Mbed TLS server keeps the SNI from the ClientHello in a
thread-local until the handshake succeeds, and its SNI callback only
runs for a ClientHello that carries one. A handshake that failed left
its SNI behind, so the next connection served by the same thread
without SNI reported the earlier client's name in req.sni(). Start
each handshake with the thread-local cleared.
SSLServer::PemMemory takes a length of 0 to mean a NUL-terminated
string for cert_pem and key_pem, but skipped client_ca_pem when its
length was 0, so a server given its client CA that way started without
requiring client certificates. Read the client CA under the same rule
as the other fields. An empty client CA now fails to load instead of
turning the check off, and the README documents the length-0 rule.
ClientImpl::open_stream built the body reader from Content-Length and Transfer-Encoding whatever the method or status, so a stream on a response that RFC 9112 6.3 ends at its header section was read on: with a keep-alive server read() blocked until the read timeout, and when the server closed it reported a read error for a complete response. stream::Head() against cpp-httplib's own server, which puts the GET body's Content-Length on a HEAD response, hit it every time.
open_stream_() now returns with the body reader at its end for a response to HEAD and for a 204 or 304, as the buffered path skips the body for them. Content-Encoding is skipped too, so a coding the build lacks no longer fails such a stream.
When pre_routing_handler or pre_request_handler answers a WebSocket upgrade request, Server::process_request returns before the drain of an unread body and closes the connection only for a 4xx/5xx. A 2xx/3xx answer to an upgrade request with a framed body left that body to be parsed as the next request on the keep-alive connection. Those two early returns now close the connection when the request has a framed body, as the Expect rejection already does.
open_stream(), and with it stream::Get() and SSEClient, wrote its own
request head and left out what a buffered request gets: the
Authorization from set_basic_auth() or set_bearer_token_auth(), and
through a plain HTTP proxy the absolute-form target (RFC 9112 3.2.2)
and Proxy-Authorization. A proxy refused such a request, and an origin
that needs credentials answered 401.
Move the two decisions out of write_request() and handle_request() into
add_credential_headers() and proxy_target_prefix(), and use them in
open_stream() too, after connecting as a buffered request does. A
Digest challenge or a redirect is still handed to the caller.
A failed request could reach the client's error logger twice: once from
the step that failed, without a request when that was the TLS setup or
the proxy CONNECT, and again from send_() with the request. A content
receiver or progress callback that canceled was reported twice too, a
CONNECT answered with 407 only without a request, and a stream that
failed to open not at all unless TLS failed.
Report a failure in one place instead. The outermost send() reports the
request's error once, with the request the caller made, also when the
failure happened on a redirect (a redirect client no longer gets the
error logger) and when an answer carries an error, such as a proxy's
407. open_stream() reports a stream that fails to open the same way.
Only an upload body compressed before send() still reports where it
fails.
A buffered request whose response body went over set_payload_max_length(),
also once decompressed, failed with Error::Read, while the Stream API
reports the same limit as Error::ExceedMaxPayloadSize. read_content()
already marks it with a 413 status, so map that status to
ExceedMaxPayloadSize next to the 415 and 500 the client maps already.
696b94b built and ran test_websocket_heartbeat in the Windows jobs to
cover the pong timeout wake, which added more than a minute to each of
them. Only its two pong timeout tests exercise what differs by
platform, and both work with the ping interval set at runtime. Move
them into test.cc, where every job runs them in its shards, and drop
the Windows heartbeat build and step.
The heartbeat file keeps CompileTimeClientReadTimeoutIsFail, whose
fixture is renamed WebSocketSilentPeerTest after the peer it sets up.
When max_missed_pongs ran out, the heartbeat thread shut down the read
side of the socket to end a read() blocked on the silent peer. On
Windows that does not wake the wait, so read() stayed blocked until its
read timeout and then returned Timeout. The heartbeat test never ran on
Windows, so CI did not catch it.
The heartbeat now sets a flag that the stream's read interrupt checks,
the mechanism SSEClient::stop() uses, and WebSocketSSLStream takes the
interrupt too. It is set only when a pong timeout can happen, so other
connections wait as before. read() reports a timeout on a connection
that has closed as Fail, since Timeout means it is still usable.
Build and run the heartbeat test in the Windows jobs, and add a TLS
pong timeout test.
The event loop reads through open_stream(), which takes the socket out
of the Client, so the client_.stop() in stop() could not reach it.
stop(), and the destructor with it, waited until the server sent
something or the read timeout passed, 300 seconds by default.
Shutting the socket down from stop() does not wake a read waiting in
WSAPoll on Windows, so 3744227 was reverted. A stream now takes an
interrupt check instead: while one is set, it waits for data in 100 ms
slices and gives up once the check returns true, as the server's
keep-alive wait does with its flag. SSEClient sets one that turns true
when stop() is called. Streams without one wait as before.
SSEIntegrationTest.ManualStop now ends its stream with the fixture's
flag. Its server outlives the test body, and the faster stop() let the
stream read a local of the body that had returned.
This reverts commit 3744227de2.
Shutting down the socket does not wake a read waiting in WSAPoll on
Windows while the peer stays silent, so stop() still waited out the read
timeout there and the new tests failed. Faster stop() on the other
platforms also let SSEIntegrationTest.ManualStop return while its server
handler still read a local of the test body (stack-use-after-return).
The fix will come back built on a wait that works on every platform.
An upgrade request goes through the pre-routing handler before the
WebSocket routes are matched. When none matched, it was routed as a
plain HTTP request, and routing() ran the handler a second time. Skip
it there for an upgrade request.
An `event:` line without a value left the type empty, so the event
never reached on_event("message"), and on_message saw an empty type.
The HTML standard dispatches an event with an empty type as
"message".
StreamHandle::read() parsed the trailers only on the path without a
decompressor, so response->trailers stayed empty for a compressed
chunked response. Parse them in one place for both paths, and only
after the last chunk: after a failed read it waited another read
timeout for a trailer line, and parse_trailers_if_needed() called
before the end read body bytes as trailers.
A response with neither Content-Length nor chunked encoding ends when
the connection closes (RFC 9112 6.3), but the stream API set
read_error() to ConnectionClosed on reaching that end, and SSEClient
passed it on to on_error. Only a body shorter than its Content-Length
is cut short there.
With follow_location on, every 3xx was taken for a redirect, so a 304
Not Modified, or any 3xx without a Location, failed with Error::Unknown.
Follow a 3xx only when it has a Location, as curl does, and return the
others as the response, as curl, Go, requests and urllib3 do. Response
handlers and content receivers now get such a response too.
With built-in verification on, a server certificate verifier returning
true made Mbed TLS accept a certificate its own check had rejected,
such as a self-signed one, while OpenSSL and wolfSSL still failed with
SSLServerVerification. On a client, keep the flags of Mbed TLS's own
verification, so the verifier is an additional check as on the other
backends. With verification off, the verifier is still the only check.
A server still clears them: there all three backends let an accepting
callback admit a client certificate.
The event loop reads through open_stream(), which takes the socket out
of the Client, so the client_.stop() in stop() could not reach it.
stop(), and the destructor with it, waited until the server sent
something or the read timeout passed, 300 seconds by default.
The loop now hands the stream's socket to stop() while it reads, and
withdraws it under the same lock before the socket is closed. stop()
shuts down the read side only: a TLS backend answers the EOF with an
alert, and writing it to a socket closed for writing raises SIGPIPE.
SSLServer, SSLClient and WebSocketClient take a PemMemory with
cert_pem_len and key_pem_len, but the lengths were never read: every
backend read the PEM up to a NUL, so a buffer holding exactly the PEM,
such as a std::vector<char> read from a file, was read past its end.
Hand on a NUL-terminated copy of the given number of bytes instead.
A length of 0 still means a NUL-terminated string, which is what
callers got before. The client CA already honored its length.
Bring the READMEs and the docs pages (en and ja) in line with the
current header:
- Fix the client sample that does not compile, the Transfer-Encoding
statement for default headers, the verifier callback comment, the
thread pool spawn rule, the sanitize_filename description, and the
inverted Accept-Encoding sentence.
- Describe recent behaviour: TLS errors behind Read/Write failures,
Host validation, Connection: close for a body without length,
content_reader rules, refused CONNECT, WebSocketClient proxies,
CPPHTTPLIB_INTERIM_RESPONSE_MAX_COUNT, the SSE event size limit, and
the payload limit of the Stream API.
- Complete the API references of WebSocket, WebSocketClient and the
stream:: helpers, and the SSE reconnect rules.
- Fix cookbook pages: keychain loading on every backend, received Close
status, a multipart sample that trusted the client's file name, an
echo sample that sent binary as text, SNI, pre-request handler scope,
stop() with WebSocket handlers, and the thread pool notes.
- Restore the mutex in the LLM app's Chapter 5 code.
WebSocketClient gets the proxy setters Client has: set_proxy(),
set_proxy_basic_auth(), set_proxy_bearer_token_auth(), set_no_proxy()
and, in SSL builds, set_proxy_digest_auth(). connect() opens a CONNECT
tunnel for ws:// as well as wss:// (RFC 6455 4.1) and sends the proxy
credentials on the CONNECT request only. A proxy that does not answer
200 is reported as Error::ProxyConnection, with its status and headers
in Result.
CURLOPT_READDATA takes a pointer, but ServerClosesConnection passed
the read_data struct itself through curl_easy_setopt()'s varargs, so
the read callback never got its state and never produced a body.
time_t is 32 bits wide on 32-bit builds, so the millisecond counts in
set_max_timeout() and the streams' duration() narrowed into it
implicitly. Cast them as duration_to_sec_and_usec() already does. In
the tests, six content receivers took a uint64_t length where
ContentReceiver passes size_t, the Expect: 100-continue test kept
10 GiB in a size_t, and the Range checks compared ssize_t fields with
unsigned literals, so they now compare whole Ranges.
DoesNotReserveTheClaimedLength shifted a size_t by 41. It now claims
std::string().max_size(), the most the client accepts, and still
fails if the reserve cap is removed.
BoringSSL counts stacks in size_t, and takes the protocol version as
uint16_t and the error code as uint32_t. Walk the certificate stacks
with the decltype(count) loop used elsewhere, pass the version as
uint16_t, and cast the error code to what ERR_get_error() returns.
MSVC takes the send() length as int, so the raw send() calls left in
the tests go through detail::send_socket().
ThreadPool::enqueue only spawned a dynamic thread when no thread was
idle. Threads already notified for an earlier job still counted as
idle until they took it, so a burst of connections could leave jobs
queued with no thread while the pool was below max_threads. With
keep-alive, such a connection waited until another connection closed.
Fix#2633
from_chars() mixed its int digit and base into the arithmetic of an
unsigned T, a sign conversion since Content-Length is parsed as size_t.
Convert both to T first.
Comparing a uint64_t with SIZE_MAX is always false on 64-bit builds,
so the WebSocket frame length and mmap size checks tripped
-Wtautological-type-limit-compare. fits_in_size_t() checks with a
round trip instead, and the Windows branch of mmap::open() uses it too.
The raw ::send() calls in the WebSocket tests passed an int length,
which POSIX takes as size_t. Use detail::send_socket(), which handles
both.
This reverts commit 28f3922. Keep the path encoding settled in #2082
(#2170) and #2608 until a concrete report needs more: user input
belongs in encode_path_component(), and an embedded NUL is invalid
input.
encode_path() sent '"', '<', '>', '\', '^', '`', '{', '|', '}', '['
and ']' raw, although RFC 3986 §3.3 doesn't allow them in a path.
Tomcat, Jetty and Undertow answer each of them with 400 by default, but
accept the percent-encoded form. It also stopped at an embedded NUL, so
"/a\0b" went out as "/a". Encode every byte outside pchar, keeping '/'
and '%' so that escapes pass through, and still encode '+', ',', ';'
and '\'' as before.
encode_request_target() now passes only the path to encode_path(). The
"http://host" of a target sent to a proxy and a CONNECT "host:port" are
sent as they are, so the brackets of an IPv6 host stay.
PemMemoryClientCertPresent now checks that the server saw the client's
certificate, as ClientCertPresent does. Before, it also passed when the
server built from PemMemory did not ask for a certificate at all.
The ClientCertPresent and ClientCertMissing helpers no longer pass
CLIENT_CA_CERT_DIR, which is "." and makes Mbed TLS parse every file in
the test directory, test binaries included, on each server they build.
The CA file is all they need. That makes TrustDirOptional, which built
the same server and client, a duplicate, so it goes. The tests that
still pass the directory keep the constructor taking one covered.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
Make ClientCertStillRequired take the setup to apply, so the
update_certs_pem test runs the same pair as the verify callback tests:
a client without a certificate is rejected and one with a certificate
is still accepted. Rejection alone would also pass if the update broke
the server for every client.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
Split the rejection scenario out of ClientCertMissing so it can run
against any server, then use it to check that a server built from
PemMemory with a client CA, and a server whose certificates were
replaced with update_certs_pem, both reject a client without a
certificate.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
On BoringSSL, SSL_get1_session() after a TLS 1.3 handshake gives a
session that cannot be resumed; the tickets come only through the
new-session callback, which its documentation recommends. Store the
session from that callback, so the resumption tests resume there too.
ThrowingVerifyCallbackRejectsTheCertificate and
ErrorAndExceptionHandlersReplaceProvider throw from a callback, which
does not compile with CPPHTTPLIB_NO_EXCEPTIONS and -fno-exceptions.
windows.h defines max() as a macro, which broke the Windows builds at
the two time_point::max() calls the handshake deadline added. Wrap them
in parentheses, as the other max() calls are.
Both sides of the merge tested the same behavior. Keep one test of
each: ClientCertStillRequired* for a server keeping client certificates
required, which covers a cleared callback too, VerifierStaysWithItsClient
for per-client verifiers across threads, and the Keep* redirect tests,
which share one helper. KeepSessionVerifier now also checks the error,
as the dropped SessionVerifier did.
Both sides keep TLS verify callbacks per context. Keep this side's
storage, which lets a handshake keep the callback it is running and
takes an exception from it as a rejection, and take the other side's
apply_verify_mode(), which works out the verify mode in one place on
every backend, with Mbed TLS and wolfSSL client contexts verifying by
default. Mbed TLS installs its verify callback on every session, and
each session runs its own copy of the user's callback. The redirect
client setup that both sides added is kept once.
name and filename are read as RFC 9110 quoted-strings, while browsers
send a backslash as it is, so from a browser a value with "\\" in it
arrives with a single backslash, and one ending in "\" is misread.
Through a plain-HTTP proxy the request line carries the absolute form,
while the Digest uri stays in origin form, as curl sends it. The comment
cited RFC 7616 3.4, which asks for the effective request URI.
A resumed handshake does not show the client certificate again, so since
OpenSSL mTLS servers resume sessions, a verify callback, such as one
checking a deny list, was skipped for as long as the ticket was good
(7200 s by default). Turn off session tickets, TLS 1.3 ones included,
and the session cache on a context with a callback, as on wolfSSL.
A server sending "102 Processing" without end kept the client reading
them unless max_timeout was set. Skip at most
CPPHTTPLIB_INTERIM_RESPONSE_MAX_COUNT (100) and fail with Error::Read
past it.
Client took any string with "//" in it that it could not use as a URL
for a bad URL, so a Unix socket path such as /run/app//api.sock gave an
invalid client. Only a string that starts with a scheme and "://", or
with "//", is taken for a URL now.
set_content_provider() and file content added their Content-Type next to
the one an earlier set_content() had set, so the response went out with
two, and clients took the first. Each content setter now replaces it. A
Content-Type set after set_file_content() is used for the file.
A content provider without a length or chunked coding sends a body that
only the end of the connection delimits (RFC 9112 6.3), yet the response
offered keep-alive, so a keep-alive client waited for the server's idle
timeout. Send Connection: close and close after it, as Go's net/http
does. A Content-Length set by the handler is still dropped; the
overload that takes a length frames such a body.
An exception from a verify callback unwound through the TLS library,
which is C: OpenSSL leaked the objects of the handshake, and a server
worker thread ended the process. It also left the handshake count that
update_certs_pem() waits on raised, so with a task queue that caught the
exception, every later update waited forever. Take the exception as a
rejection, and lower the count on every way out of the handshake.
Replacing a verify callback, as set_server_certificate_verifier() does,
deleted the one that a handshake on another thread could be running, on
OpenSSL and wolfSSL. Handshakes now share the callback and take their
reference under a lock, and SSLClient replaces it under the lock that
guards creating a session from its context.
tls::set_verify_callback() set the verify mode anew, so on a server that
required client certificates it made them optional: OpenSSL and wolfSSL
dropped SSL_VERIFY_FAIL_IF_NO_PEER_CERT, and Mbed TLS went from REQUIRED
to OPTIONAL. A client without a certificate got through. Keep what the
server requires.
update_server_client_ca() rotated the session ticket keys with 80 bytes,
which only OpenSSL takes. BoringSSL and LibreSSL take 48, refused them,
and the result was not checked, so a client went on resuming with a
ticket from before the client CA changed. Use the size each library
takes, and fail the update when the keys cannot be set.
Reset last_ssl_error_ and last_backend_error_ at the start of each
attempt in send_() rather than once in send(), so a request that
succeeds on the SSLPeerCouldBeClosed_ retry does not report the TLS
error of the attempt before it.
Now that every request writes those members, hold request_mutex_ until
the Result has read them, so another thread's request on the same
client cannot reset or replace them in between.
Also pick the TLS error up in a lambda in SSLClient::process_socket()
instead of through an out-parameter on process_client_socket_ssl(),
which has no other caller.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
A request that fails after the TLS handshake reports Error::Read or
Error::Write, and SSLSocketStream dropped the TLS error behind it. On
TLS 1.3, where a server rejects a client without a certificate only
after the handshake, ssl_error() and ssl_backend_error() were 0 instead
of showing, for example, OpenSSL's "tlsv13 alert certificate required".
SSLSocketStream now keeps the error from its last failed TLS read or
write, and SSLClient copies it into the values Result reports. Error
itself stays Read or Write.
Those values are also reset at the start of each request, so a later
successful request no longer reports the TLS error of an earlier one. A
client whose TLS context failed to set up keeps reporting that error.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
wolfSSL shares its session cache between contexts, so a session resumed
on a server that checks client certificates could carry a certificate
checked against another server's CA, or against a client CA replaced
since. Such a server no longer resumes sessions.
Without a session id context, OpenSSL answers a client resuming its
session with a fatal alert once client certificates are verified, which
curl and browsers run into on their second connection. Set one on every
server context. A changed client CA still stops resumption, as fcf7568
flushes the cache and rotates the ticket keys.
With set_ca_cert_store() after load_ca_cert_store(), the redirect client
trusted the earlier PEM too, though the store had replaced it, and of
several load_ca_cert_store() calls it kept only the last. Take the CAs
from the context when a store was set, and from every PEM loaded
otherwise.
Hostname verification on these backends fell back to the subject CN
even when the certificate had a DNS SAN, unlike X509_check_host and
RFC 6125 6.4.4. It does so only without one now. Mbed TLS also reads
the CN by its OID instead of searching the formatted DN for "CN=", and
no longer stops at an empty SAN.
The Digest uri and A2 took the raw path, while the request line carried
it encoded, with the params and without the fragment, so a server
comparing the two rejected the credentials. Build the target in one
place for both.
set_keep_alive_max_count(0) tripped an assert, a negative WebSocket ping
interval sent pings in a tight loop, and the form length, multipart file
count and range count macros rejected every request at 0. Make 0 mean
no limit for those, and a ping interval of 0 or less turn pings off. The
URI, header and line bounds cannot be lifted, so a static_assert keeps
them positive.
An event stream has no end, but the client's payload_max_length, 100MB
by default, cut it and made the client reconnect. SSEClient lifts that
limit for its stream; each event stays bounded by
CPPHTTPLIB_SSE_MAX_EVENT_LENGTH.
Files have been read with pread() since 44658e6, so the mapping went
unused. Keep only the descriptor, open it close-on-exec and without
waiting on a FIFO, and accept only a regular file, so that a device is
no longer served as an empty body.
A quoted boundary kept its quoted-pairs, as only the quotes were taken
off, and the multipart writer sent a backslash as it was, so a name
ending in one escaped the closing quote for this library's own parser.
Unescape \" and \\ in media type parameters as in Content-Disposition,
and write a backslash as \\.
append_query_params() added the parameters after a '#', where the
fragment, which is not sent, took them along, and write_request() read a
query that came after one. Insert them before the fragment, and leave
the fragment out of the query.
A response framed by Transfer-Encoding next to a Content-Length, or an
HTTP/1.0 response with Transfer-Encoding, left the connection open for
the next request, though RFC 9112 6.1 has such framing treated as faulty
and the connection closed after it. Close it, with the check the server
makes for requests now shared.
On TLS 1.3 the server rejects a client without a certificate only after
the client has finished its side of the handshake, so the client notices
either when it writes the request or when it reads the response. CI saw
the write fail on Windows (OpenSSL) and once on macOS (Mbed TLS), which
ClientCertMissing did not accept.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
get_ca_certs() handed out heap copies of the context's CA certificates,
but free_cert() frees nothing on Mbed TLS, so every copy leaked. Hand
out the context's own certificates instead, as get_peer_certs() does
the session's, and say on the declaration that they last only as long
as the context's CA certificates stay as they are.
This showed up on every redirect from a client given a store with
set_ca_cert_store(), which passes the store on through these
certificates.
The ClientCertStillRequired tests call tls::set_verify_callback(), whose
declaration lives below the split border, so test_split failed to compile.
Declare it next to create_ca_store(), which the split build needs for the
same reason.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
A content provider that wrote past the length it was given put the
extra bytes after the framed body, where a keep-alive peer read them as
the next message. Write only what fits and fail the write, on both the
server and the client.
Content-Length and Transfer-Encoding a handler set were sent next to
the ones the library worked out, for ranges and compression, and a
post-routing handler could change the body after Content-Length was
set. Work both out in one place, from the body about to be written,
again after the post-routing handler; a HEAD response keeps the length
its handler gave it. A 1xx, 204 or 304 response sends no body and,
following RFC 9110 8.6, no Content-Length.
The client still sends a Content-Length or Transfer-Encoding its caller
passes, as curl and urllib3 do, and the README says these have to match
the body.
The read timeout applied to each read of the request line and headers,
so a client that sent them a byte now and then held a worker for as
long as it liked, and enough such clients left no worker for anyone
else. Bound the whole head by the read timeout, as the TLS handshake
already is, through a new Stream::set_max_timeout() that the socket
streams implement with their existing max timeout.
A request body is still bounded per read, and a WebSocket holds its
worker for its whole life. The README says so, and points to a
reverse proxy and the pre-request handler for untrusted clients.
Use ASSERT_FALSE and FAIL() instead of their hand-written forms, drop an
unused using-directive and a comment that restated the code, and fix the
section comment that still referred to get_peer_cert().
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
ClientCertPresent() and ClientCertMissing() now take a setup step for the
server, bind to any port instead of the legacy PORT, and the two new tests
are just calls to them.
ClientCertMissing also no longer checks the server certificate: with it
checked, the request failed because cert.pem is not trusted, whether or not
the server asked for a client certificate, so the test never exercised the
client certificate requirement. A rejected client is reported as
SSLConnection, or as Read on TLS 1.3, where the client only notices on its
first read.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
set_verify_client() and set_verify_callback() each set the verify mode on
their own, and set_verify_callback() ignored whether the peer's certificate
was required. A server that required client certificates therefore stopped
requiring them as soon as a verify callback was set on its context (OpenSSL,
Mbed TLS, wolfSSL) or set and then cleared again (OpenSSL, Mbed TLS).
Compute the mode from "peer certificate required" and "callback set" in one
helper per backend and call it from set_verify_client(),
set_verify_callback() and the context constructors. The context now records
that a client verifies the server by default, so clearing a callback on a
client context restores that default.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
A retry or redirect after an early answer to Expect: 100-continue now
opens a new connection, interim responses are also skipped while
waiting for 100 Continue, and a URL Client cannot use, such as one with
userinfo, gives an invalid client. Only a 407 is passed on from a
refused CONNECT, WebSocket::close() sends only a valid payload, and the
SSE client stops on an oversized event rather than reconnect to it.
Media type parameter names and user extension mappings are matched
without case, file content is read in larger chunks from a buffer of
its own, the streaming decompression limit reports
ExceedMaxPayloadSize, and the tests use the existing single-response
server helpers. Comments and the README are brought in line.
The server fuzzer's stream exposed no buffered data, so the fast path of
stream_line_reader::getline was never fuzzed. Hand out what a read
pulled in beyond the bytes asked for, as SocketStream does.
Over TLS a file is copied out of its mapping in this process, so one
truncated while it was being served raised SIGBUS and took the whole
server down. Read it with pread, which comes up short instead.
Credentials and the client certificate stay behind; other headers,
default ones included, go along as RFC 9110 15.4 has it, and so do the
limits and the TLS settings.
A wss client could set its CAs but had no way to pin a certificate. Add
set_server_certificate_verifier() and set_session_verifier(), as
SSLClient has.
INDEX.HTML got the default type, a REMOTE_ADDR spelled in lower case got
past the guard on prohibited header names, and Multipart/Form-Data was
not taken for multipart, though RFC 9110 makes field names and media
types case-insensitive and web servers match extensions so.
OpenSSL allowed client-initiated renegotiation, which runs a handshake
update_certs_pem() does not wait for, and kept sessions and ticket keys
across a change of client CAs, so a client verified under the old ones
could resume. wolfSSL added new client CAs to the old instead of
replacing them, and a bad certificate or key left Mbed TLS and wolfSSL
half updated.
Turn renegotiation off, forget the sessions and ticket keys on a client
CA change, replace wolfSSL's CAs, and check new material before swapping
it in. Note that the update must not be called from a TLS callback.
The Mbed TLS and wolfSSL backends matched *.com, a bare *, vic*.test and
names with empty labels, which OpenSSL rejects. Require two labels after
a wildcard, none in an IDNA label and no empty label, and ignore a
trailing dot on the host, so every backend accepts the same names.
On Mbed TLS and wolfSSL the verification mode is a setting of the
context, and it was changed outside the lock that guards creating a
session from that context.
Any Close payload was echoed back, a 1-byte one, a code that may not be
sent and a reason that is not UTF-8 included. Echo a valid one and
answer the others with 1002, from one place for both read loops.
A non-200 answer to CONNECT was returned as the response, so a proxy, or
anyone on the plain leg to it, could answer an HTTPS request as if the
origin had. Fail the request with Error::ProxyConnection for anything
but a 4xx or 5xx refusal.
Only 100 Continue was skipped, and only without header fields, so a 103
Early Hints was taken for the final response and a 100 with fields threw
the parsing off. Skip every 1xx but 101, along with its header fields.
When the final response came before 100 Continue, the body was never
sent but the connection was kept, so the server could read the next
request as that body. Close it after the response.
parse_url took http://user@evil.com/ for the host "user@evil.com", where
parsers that honour userinfo, or read a backslash as '/', see evil.com.
userinfo is not supported, so reject both.
When the real path of a file under a mount point could not be resolved,
the check that it stays inside the mount point was skipped and the file
was served. Do not serve it from there, and refuse a mount point whose
directory cannot be resolved.
decode_path_component dropped a %u escape of a surrogate, joining what
was on either side of it, so /ad%uD800min became /admin after a filter
had seen something else. Keep such an escape as it is.
Any run of spaces or tabs separated the parts of the request line, a
fragment in the target was stripped, and an HTTP/1.1 request without
Host was served, so a server or a cache in front that follows RFC 9112
could see another request. Require a single SP between the parts, and
answer a target with '#' and an HTTP/1.1 request without Host with 400.
The client no longer sends the fragment of a URL.
RFC 9112 6.1 has a server close the connection after answering a
request with both Transfer-Encoding and Content-Length, or with
Transfer-Encoding in HTTP/1.0. Close it, and send Connection: close
whenever the connection closes after a response.
split_unquoted ended a quoted-string at an escaped quote, so
name="a\"; filename=evil.php" came apart into a name and a filename that
a parser in front following RFC 9110 would not see. Skip quoted-pairs
when splitting, and unescape \" and \\ in Content-Disposition values,
leaving other backslashes, such as those of a Windows path, as they are.
A part header arriving a few bytes at a time was searched for its CRLF
from the start on every read, which made parsing it quadratic. Remember
how far the search got.
The SSE client buffered a line, or the data of an event, with no limit
of its own, and with payload_max_length(0) with none at all. Add
CPPHTTPLIB_SSE_MAX_EVENT_LENGTH (16MB) and end the connection with
ExceedMaxPayloadSize past it.
Every continuation frame could be as long as the whole message limit,
and the total was checked only after appending it, so a fragmented
message could take about twice the limit. Read each fragment against
what is left, with room for a control frame between them.
The client reserved what Content-Length claimed, up to
payload_max_length, before any of the body arrived, and without a limit
nothing bounded it. Reserve at most 1 MiB up front and let a longer body
grow as it is read.
An unsupported scheme without exceptions, or a port out of range, left
Client with no implementation, so the first request after it went
through a null pointer. Put a client in its place that reports itself
invalid and fails every request with Error::Connection.
CPPHTTPLIB_WEBSOCKET_MAX_PAYLOAD_LENGTH = 0 rejected every frame with a
payload, while 0 means no limit for payload_max_length. Make it mean the
same here, and refuse a length that size_t cannot hold.
set_payload_max_length(0) means no limit, but StreamHandle compared the
decompressed size against 0, so every compressed response read through
the streaming API failed.
case_ignore::hash recursed once per character of the key, and trailer
field names from the wire reach it, so a long one could overflow the
stack of a build that keeps the recursion (-O0). Hash in a loop instead,
which gives the same values.
Remove the now-unused forward declaration and the null checks that can no
longer fire, since create_session() always sets the session and its
context before installing the callback, and shorten the comments.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
find_content_type(), can_compress_content_type() and
is_prohibited_header_name() switched on a 26-bit hash of the name and
never compared the name itself, so any name that hashed alike was taken
for a known one. An uploaded file with an unknown extension could be
served as text/html, for one.
Compare the names themselves, and drop the hash and its literal
operator, which nothing else uses.
Every session now gets mbedtls_verify_callback(), which reads the user's
callback from the owning context when the handshake runs. The
has_verify_callback flag and the separate hostname-masking callback are no
longer needed, and a callback set after a session was created is still
honoured.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
* Carry the server certificate verifier over to the redirect client
create_redirect_client() now copies the CA store and the session verifier
to the SSLClient it builds for a cross-host https redirect (#2632), but a
verifier given to set_server_certificate_verifier() was still dropped: the
redirect client's ctx never had the verify callback wired in, so a
pinning verifier never ran on the host the server redirects to.
SSLClient now keeps its own copy of the verifier, since ctx_ cannot report
it back and the backends hold it in a slot shared by every client, and
installs it on the redirect client. The copy also replaces the
Windows-only server_certificate_verifier_set_ flag.
SSLClientRedirectTest.ServerCertificateVerifier fails before this change
and passes after (OpenSSL 3, Mbed TLS 2.28, wolfSSL 5.6).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
* Clarify the server_certificate_verifier_ comment
The backends keep the verify callback in a per-thread slot, not one
shared by every client.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
---------
Co-authored-by: Claude <noreply@anthropic.com>
tls::set_verify_callback() kept the callback in a thread_local slot, so two
SSLClients configured on one thread overwrote each other's verifier, and a
client used from another thread ran none. Keep it with the context instead
(OpenSSL SSL_CTX ex_data, MbedTlsContext/WolfSSLContext member) and have each
backend trampoline look it up from the session's context.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013wxevjmRqzpy8qDAD3vdwr
update_certs_pem() replaced the certificate, key and client CAs inside
the TLS context while handshakes on other threads were still reading
them, and only the creation of a session was serialized with it. A
server rotating its certificates under load could crash.
Count the handshakes in progress, make an update wait until there are
none, and hold off new handshakes while an update is pending so that a
steady stream of them cannot keep it waiting. The wait is bounded by
the handshake timeout.
The handshake loops gave every wait for the socket the full timeout
again, so a peer that sent a byte now and then kept a handshake going,
and the worker serving it, for as long as it liked. Work out the
deadline once and wait only for what is left of it, on both sides and in
every backend.
A cross-host redirect is followed by a new client, which did not get the
payload limit, the max timeout, the connection timeout's microseconds or
the hostname address map. Over HTTPS it also lost the session verifier,
the server certificate verifier and a store given to set_ca_cert_store(),
and fell back to the default CAs. Copy them over. The store belongs to
the original TLS context, so pass on the CA certificates it holds as PEM.
After the redirect, the original client also answered a 401 or 407 from
the new host with its own digest credentials and sent that to its own
host, with the new host's path. Return the redirected response as it is,
since the client that followed it has already answered what it could.
read_websocket_frame() resized the payload to the length a frame header
declared before reading any of it, so a 14-byte header made the peer
allocate and zero-fill up to CPPHTTPLIB_WEBSOCKET_MAX_PAYLOAD_LENGTH and
hold it until the read timed out. 70 such headers took a server to over
1 GB, and a client reading from a hostile server was exposed the same way.
Read the payload in CPPHTTPLIB_RECV_BUFSIZ chunks and grow it by each one,
so memory follows the bytes that actually came in.
std::regex_match recursed once per character of a status line's reason
phrase, so a server that sent one as long as a whole line overflowed the
client's stack. file_extension() and append_query_params() ran the same
kind of regex over a request path and a caller's path.
Parse all three by hand, with the same results, except that a path that
starts with '?' now gets its parameters joined with '&'. Serving a static
file no longer defers the content type lookup to keep a regex off the 304
path, so it looks the type up once.
FileContentProviderStaysWithinFile, added in e374966, calls
detail::set_file_content_provider, which split.py moves into httplib.cc,
so test_split did not compile. Declare it in the test, as the other tests
that call into detail:: already do.
When a content receiver returned false, or threw, partway through a body,
the drain after the response read a whole Content-Length again from where
it stopped. It swallowed the start of the next request, so the rest was
parsed as a request of its own once the handler answered below 400. A
handler that called the content reader a second time read into the next
request the same way.
Mark the body once reading starts, and if it does not finish, answer with
Connection: close and never drain it from the middle. Let each request's
body be read only once.
The wolfSSL verify callback set VerifyContext::session to the raw WOLFSSL
pointer, while every other tls:: function takes the WolfSSLSession that
wraps it, so passing ctx.session on from a verifier read the wrong type.
Point each WOLFSSL back to its WolfSSLSession and hand that out instead,
as the OpenSSL and Mbed TLS backends already do with their own handles.
tls::set_verify_callback(), which set_server_certificate_verifier() uses,
stored the callback in a single thread_local slot shared by every context.
A verifier was skipped when the handshake ran on another thread, ran for
other clients on the thread that set it, and could run after its client
was destroyed.
Store it with the context instead: in SSL_CTX ex_data for OpenSSL, and in
MbedTlsContext and WolfSSLContext for Mbed TLS and wolfSSL.
set_content() did not drop a content provider installed earlier, and
apply_ranges() then took the body's size as the Content-Length while the
provider was still the one written. The provider was asked for more bytes
than it had: a file under a mount point went out under the error status a
file request handler set to hide it, its mapping was read past the end,
and a user provider read past its own data.
Make every content setter clear the other sources so the last one wins,
let a body assigned directly after a provider or a file win as well, and
never read past the mapping in the file content provider.
glibc runs getaddrinfo_a() lookups in a thread it creates internally,
bypassing the pthread_create interceptor, so TSan never initializes that
thread and it crashes on its first allocation. Detect TSan (GCC's
__SANITIZE_THREAD__ / Clang's __has_feature(thread_sanitizer)) and use the
existing std::thread-based fallback instead, which keeps the lookup timeout
working. Non-TSan builds are unchanged.
Drop the thread_local std::mt19937 so multipart boundaries and the Digest
cnonce come from the same non-deterministic source as the WebSocket
masking key. This removes the last mt19937 from httplib.h.
Draw the masking key and Sec-WebSocket-Key directly from std::random_device instead of a std::mt19937 seeded once with 32 bits, as RFC 6455 Section 5.3 requires an unpredictable masking key. Taking the bytes one at a time also fixes an all-zero key on 64-bit big-endian builds, where the 4-byte memcpy from the 64-bit result_type copied the zero high half.
* Redirect a directory request with a relative Location
The trailing-slash redirect used the request path as-is, so a path
starting with "//" produced a Location that clients read as a
network-path reference to another host. Name only the last segment,
percent-encoded and prefixed with "./", so the target always resolves
against the request URL, whatever the mount point or any prefix a
proxy put in front of it.
* Shorten the relative redirect comment
A directory request without a trailing slash was redirected to the path
relative to the mount point, so /mount/dir under a mount at /mount sent
Location: //dir/ instead of /mount/dir/. Redirect to the request path
with the slash appended.
2026-10-14 15:35:27 -04:00
92 changed files with 8337 additions and 2491 deletions
The client reconnects when it cannot connect or the stream ends. A status other than `200` calls `on_error(Error::Connection)`; a `204`, `403` or `404` then stops the client, and any other status, `401` included, reconnects, so an `on_error` handler can refresh credentials with `set_headers()`. `set_max_reconnect_attempts()` counts reconnect attempts in a row: the count starts over after each successful connection. Each attempt that fails to connect is also reported to the `Client`'s error logger.
An event, or a line still waiting for its end, longer than `CPPHTTPLIB_SSE_MAX_EVENT_LENGTH` (16MB by default, `0` for no limit) ends the connection with `Error::ExceedMaxPayloadSize`, and the client stops rather than reconnect to the same event. The client's `set_payload_max_length()` does not apply to the stream as a whole, which has no end.
- **Large file downloads** with progress tracking (mind the [payload size limit](#payload-size-limit))
- **Reverse proxy implementations**
## Quick Start
@@ -62,7 +62,7 @@ cpp-httplib provides multiple API layers for different use cases:
| Use Case | Recommended API |
|----------|----------------|
| SSE with auto-reconnect | `SSEClient` (see [README-sse.md](README-sse.md)) |
| LLM streaming (JSON Lines) | `stream::Get()` |
| LLM streaming (JSON Lines) | `stream::Post()` or `stream::Get()` |
| Large file download | `stream::Get()` or `open_stream()` |
| Reverse proxy | `open_stream()` |
| Small responses with Keep-Alive | `Client::Get()` |
@@ -106,6 +106,8 @@ if (handle.is_valid()) {
| `get_read_error()` | `Error` | Get the last read error |
| `has_read_error()` | `bool` | Check if a read error occurred |
For a chunked response, the trailers are in `response->trailers` once `read()` has reached the end of the body.
### High-Level API: `stream::Get()` and `stream::Result`
The `httplib.h` header provides a more ergonomic iterator-style API.
@@ -137,6 +139,30 @@ if (result2) {
}
```
#### Helpers
There is a helper for each HTTP method. The arguments in brackets can be left out, and every helper takes a trailing `size_t chunk_size = 8192`, the most bytes one `next()` returns.
autores=cli.Get("/api/data");// Connection can be reused
```
### Payload Size Limit
`open_stream()` and the `stream::` helpers apply the client's `set_payload_max_length()` (100MB by default, `CPPHTTPLIB_PAYLOAD_MAX_LENGTH`) to the body, both as received and after decompression. Past the limit, `read()` and `next()` stop, and the read error is `Error::ExceedMaxPayloadSize`. To download something larger, raise the limit, or call `cli.set_payload_max_length(0)` for no limit.
### Authentication and Proxies
A stream request carries the same credentials as `client.Get()`: `set_basic_auth()` and `set_bearer_token_auth()` for the origin, and the proxy's own through `set_proxy()`, over HTTP or through a CONNECT tunnel. It does not answer a Digest challenge or follow a redirect: the `401` or `3xx` response is handed to you.
## Related
- [Issue #2269](https://github.com/yhirose/cpp-httplib/issues/2269) - Original feature request
@@ -6,7 +6,7 @@ A simple, blocking WebSocket implementation for C++11.
> This is a blocking I/O WebSocket implementation using a thread-per-connection model (plus one heartbeat thread per connection). It is intended for small- to mid-scale workloads; handling large numbers of simultaneous WebSocket connections is outside the design target of this library. If you need high-concurrency WebSocket support with non-blocking/async I/O (e.g., thousands of simultaneous connections), this is not the one that you want.
> [!NOTE]
> WebSocket extensions (`permessage-deflate` and others defined by RFC 6455) are **not supported**. If a client proposes an extension via `Sec-WebSocket-Extensions`, the server silently declines it — the negotiated connection always runs without extensions.
> WebSocket extensions (such as `permessage-deflate`, RFC 7692) are **not supported**. If a client proposes an extension via `Sec-WebSocket-Extensions`, the server silently declines it — the negotiated connection always runs without extensions.
## Features
@@ -126,7 +126,7 @@ The `SubProtocolSelector` receives the list of subprotocols proposed by the clie
Passed to the handler registered with `Server::WebSocket()`. The handler runs in a dedicated thread per connection.
```cpp
// Read next message (blocks until received, returns Fail/Text/Binary)
// Read next message (blocks until received, returns Fail/Text/Binary/Timeout)
The server accepts a handshake from any `Origin`. A browser sends its cookies with a handshake another site starts, so if cookies authenticate the connection, also check `req.get_header_value("Origin")` against your own origins in one of these handlers (cross-site WebSocket hijacking).
| `CPPHTTPLIB_WEBSOCKET_SERVER_READ_TIMEOUT_SECOND` | `300` | Server read timeout (seconds) |
| `CPPHTTPLIB_WEBSOCKET_CLOSE_TIMEOUT_SECOND` | `5` | Timeout for waiting peer's Close response (seconds) |
@@ -478,7 +527,7 @@ With the default ping interval of 30 seconds, `max_missed_pongs = 2` detects a d
## Threading Model
WebSocket connections share the same thread pool as HTTP requests. Each WebSocket connection occupies one thread for its entire lifetime.
WebSocket connections share the same thread pool as HTTP requests. Each WebSocket connection occupies one thread for its entire lifetime, so a client opening many of them can leave none for HTTP requests. Reject the upgrades you do not want in `set_pre_request_handler()`, before the connection takes a thread for good.
The default thread pool uses dynamic scaling: it maintains a base thread count of `CPPHTTPLIB_THREAD_POOL_COUNT` (8 or `std::thread::hardware_concurrency() - 1`, whichever is greater) and can scale up to 4x that count under load (`CPPHTTPLIB_THREAD_POOL_MAX_COUNT`). When all base threads are busy, temporary threads are spawned automatically up to the maximum. These dynamic threads exit after an idle timeout (`CPPHTTPLIB_THREAD_POOL_IDLE_TIMEOUT`, default 3 seconds).
@@ -71,10 +71,15 @@ cpp-httplib supports multiple TLS backends through an abstraction layer:
| wolfSSL | `CPPHTTPLIB_WOLFSSL_SUPPORT` | `libwolfssl` | 5.x supported; must build with `--enable-opensslall` |
> [!NOTE]
> **wolfSSL limitation:** `get_ca_certs()` and `get_ca_names()` only reflect CA certificates loaded via `load_ca_cert_store()`. Certificates loaded through `set_ca_cert_path()` or system certificates (`load_system_certs`) are not enumerable.
> **wolfSSL limitation:** `get_ca_certs()` and `get_ca_names()` only reflect CA certificates loaded via `load_ca_cert_store()` or `set_ca_cert_store()`. Certificates loaded through `set_ca_cert_path()` or system certificates (`load_system_certs`) are not enumerable.
>
> A wolfSSL server that verifies client certificates does not resume TLS sessions: wolfSSL shares its session cache between contexts, so a resumed session could carry a certificate checked against another server's client CA.
> [!NOTE]
> **BoringSSL (best-effort):** BoringSSL builds under `CPPHTTPLIB_OPENSSL_SUPPORT` and is exercised by CI against current upstream. Because BoringSSL does not guarantee API stability, support is best-effort — breakage may occasionally land. Two known behavioral differences vs OpenSSL: (1) BoringSSL's public headers require C++14 or later, so consumers must compile accordingly; (2) hostname verification is SAN-only per RFC 6125 §6.4.4 (no CN fallback).
> **BoringSSL (best-effort):** BoringSSL builds under `CPPHTTPLIB_OPENSSL_SUPPORT` and is exercised by CI against current upstream. Because BoringSSL does not guarantee API stability, support is best-effort — breakage may occasionally land. One known difference vs OpenSSL: BoringSSL's public headers require C++14 or later, so consumers must compile accordingly.
> [!NOTE]
> **Hostname verification is SAN-only on every backend** (RFC 9525). A host is matched against the certificate's subjectAltName entries, never its Common Name, so a certificate that names its host only in the CN is rejected. Reissue it with a subjectAltName.
> The CA certificates are loaded when the client makes its first connection. Changing `set_ca_cert_path()` or `enable_system_ca()` after that has no effect, so make the settings before the first request, or use a new client. `set_ca_cert_store()` and `load_ca_cert_store()` take effect at once. `WebSocketClient` works the same way. On `Client` and `SSLClient`, a setter that changes a TLS setting also closes a connection kept alive under the old one, so the next request connects again.
### SSL Error Handling
When SSL operations fail, cpp-httplib provides detailed error information through `ssl_error()` and `ssl_backend_error()`:
- `ssl_error()` - Returns the TLS-level error as a backend-independent `httplib::tls::ErrorCode` value (e.g., `Fatal`, `CertVerifyFailed`), cast to `int`
- `ssl_backend_error()` - Returns the backend-specific error code (e.g., `ERR_get_error()` for OpenSSL/wolfSSL, return value for Mbed TLS). With OpenSSL, a certificate verification failure reports the verify result (`X509_V_ERR_*`) here instead
- `ssl_error()` - Returns the TLS-level error as a backend-independent `httplib::tls::ErrorCode` value (e.g., `Fatal`, `CertVerifyFailed`), cast to `int`. A server certificate that the built-in verification rejects reports `CertVerifyFailed`, or `HostnameMismatch` when only its name does not match
- `ssl_backend_error()` - Returns the backend-specific error code (e.g., `ERR_get_error()` for OpenSSL/wolfSSL, return value for Mbed TLS). With OpenSSL, a certificate verification failure reports the verify result (`X509_V_ERR_*`) here instead. On Windows, when CryptoAPI verifies the chain, a failure there reports the CryptoAPI error code here
A request that fails after the handshake with `Error::Read` or `Error::Write` also carries the TLS error behind it in both values, such as a TLS 1.3 "certificate required" alert from the server. Both values are reset for each request.
```c++
#define CPPHTTPLIB_OPENSSL_SUPPORT // or CPPHTTPLIB_MBEDTLS_SUPPORT or CPPHTTPLIB_WOLFSSL_SUPPORT
Returning `false`, or throwing, rejects the certificate. The callback runs alongside the built-in verification, so to accept a certificate that verification rejects, such as a self-signed one, also call `enable_server_certificate_verification(false)`; the callback is then the only check.
### Mutual TLS (mTLS)
Regular TLS only verifies the server certificate. With mTLS, the client also presents a certificate that the server verifies.
A length of 0 means the field is a NUL-terminated string.
`httplib::ws::WebSocketClient` has the same `PemMemory` constructor for `wss://` connections. See [README-websocket.md](README-websocket.md) for details.
### Peer Certificate Inspection
@@ -229,17 +243,21 @@ cpp-httplib automatically integrates with the OS certificate store on macOS and
| Platform | Behavior | Disable (compile time) |
| :------- | :------- | :--------------------- |
| macOS | Loads system certs from Keychain (link `CoreFoundation` and `Security` with `-framework`). Requires Apple Clang; GCC is not supported for this feature. | `CPPHTTPLIB_DISABLE_MACOSX_AUTOMATIC_ROOT_CERTIFICATES` |
| macOS | Loads system certs from Keychain, honouring their Trust Settings: a certificate set to "Never Trust", or trusted only for another policy such as S/MIME, is not loaded (link `CoreFoundation` and `Security` with `-framework`). Requires Apple Clang; GCC is not supported for this feature. | `CPPHTTPLIB_DISABLE_MACOSX_AUTOMATIC_ROOT_CERTIFICATES` |
| Windows | Verifies the certificate chain with CryptoAPI (`CertGetCertificateChain` / `CertVerifyCertificateChainPolicy`) instead of the TLS backend. Revocation checking is best-effort: a revoked server certificate is rejected, while one whose revocation status cannot be determined is accepted. Windows fetches missing roots and intermediates on demand. With a custom CA, the TLS backend verifies the chain instead; with `set_server_certificate_verifier()`, both do. | `CPPHTTPLIB_DISABLE_WINDOWS_AUTOMATIC_ROOT_CERTIFICATES_UPDATE` |
On Windows, verification can also be disabled at runtime:
On Windows, the CryptoAPI check can also be turned off at runtime. The TLS backend then verifies the chain instead, as on other platforms:
`WebSocketClient` does not use CryptoAPI; the TLS backend always verifies its chain.
> [!NOTE]
> When using SSL, it seems impossible to avoid SIGPIPE in all cases, since on some operating systems, SIGPIPE can only be suppressed on a per-message basis, but there is no way to make the OpenSSL library do so for its internal communications. If your program needs to avoid being terminated on SIGPIPE, the only fully general way might be to set up a signal handler for SIGPIPE to handle or ignore it yourself.
>
> On systems other than Windows, the `Server` constructor does this already: it calls `signal(SIGPIPE, SIG_IGN)`, which affects the whole process. A program that only uses clients has to do it itself.
## Server
@@ -335,11 +353,13 @@ Patterns work exactly as they do for `Get` and the other methods, so regular exp
Note the following:
* The method name must be a valid HTTP method token (RFC 9110) and must be registered before `listen()` is called.
* `GET`, `HEAD`, `POST`, `PUT`, `DELETE`, `CONNECT`, `OPTIONS`, `TRACE`, `PATCH` and `PRI` cannot be registered this way. Use the dedicated methods above instead.
* `GET`, `HEAD`, `POST`, `PUT`, `DELETE`, `CONNECT`, `OPTIONS`, `TRACE`, `PATCH` and `PRI` cannot be registered this way. Use `Get` (which also serves `HEAD`), `Post`, `Put`, `Delete`, `Options` or `Patch` instead. There are no handlers for `CONNECT`, `TRACE` and `PRI`; such requests get `400 Bad Request`.
* A rejected registration makes `is_valid()` return `false`, and `listen()` then fails rather than starting a server with a route that would never fire.
* `Allow` and the WebDAV `DAV:` header are not generated automatically. Register an `Options` handler if clients need them.
The request line and the `Host` header are read strictly, as RFC 9112 asks: a single space between the three parts of the request line, `HTTP/1.0` or `HTTP/1.1` as the version, no fragment (`#...`) in the target, and exactly one valid `Host` header (an HTTP/1.0 request may have none). Anything else gets `400 Bad Request`.
### Bind a socket to multiple interfaces and any available port
```cpp
@@ -389,6 +409,8 @@ ret = svr.remove_mount_point("/");
ret = svr.remove_mount_point("/public");
```
A mount point serves a path only when it has no `.`, `..` or empty segment other than a trailing `/`, no segment ending in `.` or a space and, on Windows, no `:` (it names an NTFS stream), so a check on `req.path` in `set_pre_routing_handler()` sees the path of the file that is served. A path ending in `/`, and the mount point itself such as `/public`, serve the `index.html` in that directory. The file system can still give a file other names: another case on a case-insensitive file system, such as the default ones on macOS and Windows, and on Windows an 8.3 short name such as `PRIVAT~1`. Compare paths without regard to case on such a file system, and on Windows keep files that need a guard out of mounted directories.
```cpp
// User defined file extension and MIME type mappings
Extensions match regardless of case, so `photo.JPG` is served as `image/jpeg`. The extension of a user mapping can be given in any case, with or without a leading `.`.
It is not called for `HEAD` requests or `304 Not Modified` responses, so do not use it for access control; use `set_pre_routing_handler()`.
### Logging
cpp-httplib provides separate logging capabilities for access logs and error logs, similar to web servers like Nginx and Apache.
#### Access Logging
Access loggers capture successful HTTP requests and responses:
Access loggers capture each request and the response written for it, including the error responses the library writes itself, such as `400`, `404`, `413` or `500`:
The pre-compression logger is only called when compression would be applied. For responses without compression, only the access logger is called.
The pre-compression logger is only called when the server compresses `res.body` or a static file. It is not called for a response without compression, nor for a chunked content provider, whose body is compressed as it is written; for those, only the access logger is called.
For a static file response (see [Static file compression](#static-file-compression)), `res.body` is empty when the logger runs. The bytes are still on disk at that point, not in memory.
The exception handler gets called if a user routing handler throws an error.
The exception handler gets called if a user routing handler throws an error. This covers the pre-routing handler, the file request handler, the pre-request handler, route handlers, content readers and, on a WebSocket upgrade, the sub-protocol selector. The response is a 500 unless the exception handler sets another status. An exception from the post-routing handler, the error handler, the `Expect: 100-continue` handler, a content provider, a logger or a WebSocket handler does not reach it: the connection is dropped, and the error logger receives `Error::UserCallbackException`.
│ └─ returns Handled → go straight to post_routing_handler
│
├─ file_request_handler when a static file is served (GET only)
│ └─ a mount point answered → go straight to post_routing_handler
│
├─ route matching → req.matched_route is set
│
@@ -589,7 +616,7 @@ Request received
On an error status (4xx/5xx) → error_handler
```
Use `pre_routing_handler` to reject a request as early as possible, before the route is known. Use `pre_request_handler` for route-specific checks, since `req.matched_route` is available and the body has not been read yet.
Use `pre_routing_handler` to reject a request as early as possible, before the route is known. Use `pre_request_handler` for route-specific checks, since `req.matched_route` is available and the body has not been read yet. A request that a mount point answers never reaches route matching or `pre_request_handler`, so reject such a request in `pre_routing_handler`.
For a request with `Expect: 100-continue`, the `100 Continue` response is not sent until the body is about to be read. A request rejected before that point (by `pre_routing_handler`, `pre_request_handler`, or because no route matched) gets its final response without `100 Continue`, so the client never sends the body.
auto safe = httplib::sanitize_filename(file.filename);
```
This function strips path separators (`/`, `\`), null bytes, leading/trailing whitespace, and rejects `.` and `..`. Returns an empty string if the filename is unsafe.
This function keeps only the part after the last `/` or `\`, removes null bytes, and trims leading and trailing spaces and tabs. It returns an empty string if what is left is empty, `.` or `..`.
> [!NOTE]
> `name` and `filename` are read as quoted-strings (RFC 9110 §5.6.4), where `\"` and `\\` stand for `"` and `\`. Browsers send a backslash as it is, so from a browser, a value with `\\` in it arrives with a single `\`, and one that ends in `\` is not read correctly.
Write at most `length` bytes per call. Anything past it is not sent, and the response fails. The response also fails if a call returns `true` without writing anything, or if `sink.done()` is called before the whole content length is written.
Such a body ends where the connection does, so the server sends `Connection: close` and closes the connection after the response. Use `set_chunked_content_provider()` to keep the connection open.
svr.set_keep_alive_max_count(2);// Default is 100, 0 for no limit
svr.set_keep_alive_timeout(10);// Default is 5
```
### Client address behind a reverse proxy
```cpp
svr.set_trusted_proxies({"10.0.0.2"});
```
A request that comes straight from one of these addresses gets `req.remote_addr` from `X-Forwarded-For`: the rightmost address in it that is not a trusted proxy. A request from anywhere else keeps the address of its connection, whatever `X-Forwarded-For` says. Addresses match as IP addresses, so an IPv4 peer that a server listening on both IPv4 and IPv6 sees as `::ffff:10.0.0.2` matches `10.0.0.2`. Host names and CIDR ranges are not supported.
The read timeout bounds the request line and headers as a whole, and each read of a request body. An error response closes the connection. Any other response to a request whose body was left unread, such as a redirect from a pre-routing handler, keeps the connection only when the rest of the body is at most `CPPHTTPLIB_UNREAD_PAYLOAD_MAX_LENGTH` (256KB, `0` for no limit) and arrives within the read timeout, since the server has to read past it first.
### Set maximum payload length for reading a request body
The default is `CPPHTTPLIB_PAYLOAD_MAX_LENGTH` (100MB), and `0` means no limit. A request with a larger body gets `413 Payload Too Large`.
> [!NOTE]
> When the request body content type is 'www-form-urlencoded', the actual payload length shouldn't exceed `CPPHTTPLIB_FORM_URL_ENCODED_PAYLOAD_MAX_LENGTH`.
> When the request body content type is `application/x-www-form-urlencoded`, the body must not exceed `CPPHTTPLIB_FORM_URL_ENCODED_PAYLOAD_MAX_LENGTH` (8192 bytes by default, `0` for no limit). A larger one gets `413 Payload Too Large`.
### Server-Sent Events
@@ -908,7 +960,9 @@ Please see [Server example](https://github.com/yhirose/cpp-httplib/blob/master/e
`ThreadPool` is used as the **default** task queue, with dynamic scaling support. By default, it maintains a base thread count of 8 or `std::thread::hardware_concurrency() - 1` (whichever is greater), and can scale up to 4x that count under load. You can change these with `CPPHTTPLIB_THREAD_POOL_COUNT` and `CPPHTTPLIB_THREAD_POOL_MAX_COUNT`.
When all threads are busy and a new task arrives, a temporary thread is spawned (up to the maximum). A dynamic thread exits automatically once it has waited for the idle timeout without receiving a task. The idle timeout defaults to 3 seconds, configurable via `CPPHTTPLIB_THREAD_POOL_IDLE_TIMEOUT`.
When a new task arrives and the queued tasks outnumber the idle threads, a temporary thread is spawned (up to the maximum). A dynamic thread exits automatically once it has waited for the idle timeout without receiving a task. The idle timeout defaults to 3 seconds, configurable via `CPPHTTPLIB_THREAD_POOL_IDLE_TIMEOUT`.
A connection holds its thread while it is served: between requests up to the keep-alive timeout, through a request body sent slowly but within the read timeout, and for the whole life of a WebSocket. Enough of them leave no thread for anyone else, so in front of untrusted clients, put a reverse proxy that limits connections per client, and reject unwanted WebSocket upgrades in the pre-request handler.
Each failed request is reported once, with the request you made, also when it failed on a redirect or was a stream that failed to open (`open_stream()`, `stream::Get()`).
### GET with HTTP headers
```c++
@@ -1116,6 +1172,8 @@ cli.set_default_headers({
auto res = cli.Get("/hi");
```
A `Content-Length` among these headers is sent in place of the one the library would send, so it has to match the body as written. A `Transfer-Encoding` is sent in addition to the library's own framing, so leave it out. Leave both out when passing on the headers of another message, as a proxy does.
`set_max_timeout()` is similar to curl's `--max-time` option, but the deadline only shortens the waits for reading the response. Connecting and writing are bounded by the connection and write timeouts.
### Set maximum payload length for reading a response body
A response body over the limit, also once decompressed, fails the request with `Error::ExceedMaxPayloadSize`.
### Receive content with a content receiver
```c++
@@ -1243,8 +1305,8 @@ std::string body;
auto res = cli.Get(
"/stream", Headers(),
[&](const Response &response) {
EXPECT_EQ(StatusCode::OK_200, response.status);
return true; // return 'false' if you want to cancel the request.
// return 'false' if you want to cancel the request.
return response.status == StatusCode::OK_200;
},
[&](const char *data, size_t data_length) {
body.append(data, data_length);
@@ -1266,6 +1328,8 @@ auto res = cli.Post(
"text/plain");
```
As on the server, write at most `length` bytes per call. The request fails with `Error::Write` if a call writes more, returns `true` without writing anything, or calls `sink.done()` before the whole content length is written.
> A TLS backend (OpenSSL, Mbed TLS, or wolfSSL) is required for Digest Authentication.
When the proxy refuses the `CONNECT` of an HTTPS request, the request fails with `Error::ProxyConnection`. Only a `407 Proxy Authentication Required` comes back as the response, since any other answer from the proxy could be taken for the origin's.
#### Bypass the proxy for specific hosts (`NO_PROXY`)
```cpp
@@ -1343,6 +1409,10 @@ Hostname matching is case-insensitive with a dot-boundary rule. See the
`set_proxy_digest_auth()` and `set_no_proxy()` are also available on
`httplib::ws::WebSocketClient`.
### Range
```cpp
@@ -1388,10 +1458,16 @@ res = cli.Get("/");
res->status; // 200
```
A URL with userinfo (`http://user:pass@host/`) is not supported, neither for a `Client` nor in a `Location`; use `set_basic_auth()` for the credentials. A `Client` constructed from a URL it cannot use, such as one with userinfo, a backslash in the authority or an invalid port, is not valid: `is_valid()` returns `false`, and every request fails with `Error::Connection`.
On a redirect to another origin (a different scheme, host or port), `Authorization`, `Cookie` and `Proxy-Authorization` are dropped along with the credentials set with `set_basic_auth()`, `set_bearer_token_auth()` and `set_digest_auth()`, and the client certificate is not presented. Other headers, the default ones included, go along (RFC 9110 §15.4), and so do the timeouts, the payload limit and the TLS verification settings. The TLS settings pass only from one HTTPS hop to the next: an HTTPS hop that follows a plain HTTP one starts over with the defaults, verifying against the system CAs with no verifier set. A `303` that turns a request into a `GET` drops its headers and body; only on the same origin are the default headers sent again.
Up to `CPPHTTPLIB_REDIRECT_MAX_COUNT` (20 by default) redirects are followed for a request; one more fails it with `Error::ExceedRedirectCount`. Interim `1xx` responses before the final response are skipped, up to `CPPHTTPLIB_INTERIM_RESPONSE_MAX_COUNT` (100 by default); one more fails the request with `Error::Read`.
### Use a specific network interface
> [!NOTE]
> This feature is not available on Windows, yet.
> This feature is not available on Windows, Android, AIX and z/OS. The setting is ignored there.
```cpp
cli.set_interface("eth0"); // Interface name, IP address or host name
@@ -1440,13 +1516,15 @@ auto res = cli.Get("/path with spaces/file.txt"); // Automatically encodes space
// Disable automatic path encoding
cli.set_path_encode(false);
auto res = cli.Get("/already%20encoded/path"); // Use pre-encoded paths
res = cli.Get("/already%20encoded/path"); // Use pre-encoded paths
```
- `set_path_encode(bool on)` - Controls automatic encoding of special characters in URL paths
- `true` (default): Automatically encodes spaces, plus signs, newlines, and other special characters
- `false`: Sends paths as-is without encoding (useful for pre-encoded URLs)
A fragment (`#...`) in the path is never sent, whatever the setting.
### Performance Note for Local Connections
> [!WARNING]
@@ -1491,7 +1569,7 @@ auto second = req.get_header_value("Accept-Encoding", "", 1); // "br"
## Payload Limit
The maximum payload body size is limited to 100MB by default for both server and client. You can change it with `set_payload_max_length()` or by defining `CPPHTTPLIB_PAYLOAD_MAX_LENGTH` at compile time. Setting it to `0` disables the limit entirely. On the client, a request made with a content receiver is not limited unless you call `set_payload_max_length()` yourself, so that a large download can be streamed without raising the limit first.
The maximum payload body size is limited to 100MB by default for both server and client. You can change it with `set_payload_max_length()` or by defining `CPPHTTPLIB_PAYLOAD_MAX_LENGTH` at compile time. Setting it to `0` disables the limit entirely. On the client, a request made with a content receiver is not limited unless you call `set_payload_max_length()` yourself, so that a large download can be streamed without raising the limit first. The [Stream API](#stream-api) is limited either way.
## Compression
@@ -1523,6 +1601,8 @@ This holds for every kind of response, including the file-backed ones below.
`Vary: Accept-Encoding` is added only to responses the server encoded itself. A handler that chooses between an encoded and an identity representation by reading `Accept-Encoding` should set the field itself, so that shared caches keep the two apart.
Turn this compression off with `svr.set_compress(false)`. Over HTTPS, the length of a compressed response can give away a secret in it, such as a CSRF token, when the same response also carries text an attacker can choose (the BREACH attack). A server whose responses mix the two should turn compression off, or keep such secrets out of those responses. Static file compression, below, is set separately.
### Static file compression
Responses served from a file, whether through `set_mount_point()` or `Response::set_file_content()`, are sent as is by default. Turn compression on for them with:
@@ -1565,14 +1645,14 @@ Please see https://github.com/facebook/zstd for more detail.
### Default `Accept-Encoding` value
The default `Accept-Encoding` value contains all possible compression types. So, the following two examples are same.
The default `Accept-Encoding` value lists the compression types the library is built with. It is not added to a request made with a content receiver. So, with Brotli, zlib and Zstd support all enabled, the following two examples are the same.
```c++
res = cli.Get("/resource/foo");
res = cli.Get("/resource/foo", httplib::Headers{{"Accept-Encoding", "br, gzip, deflate, zstd"}});
```
If we don't want a response without compression, we have to set `Accept-Encoding` to an empty string. This behavior is similar to curl.
If we want a response without compression, we have to set `Accept-Encoding` to an empty string. This behavior is similar to curl.
```c++
res = cli.Get("/resource/foo", httplib::Headers{{"Accept-Encoding", ""}});
@@ -1585,7 +1665,7 @@ cli.set_compress(true);
res = cli.Post("/resource/foo", "...", "text/plain");
"my-socket.sock" can be a relative path or an absolute path. Your application must have the appropriate permissions for the path. You can also use an abstract socket address on Linux. To use an abstract socket address, prepend a null byte ('\x00') to the path.
This library automatically sets the Host header to "localhost" for Unix socket connections, similar to curl's behavior:
This library automatically sets the Host header to "localhost" for Unix socket connections, similar to curl's behavior.
- `encode_uri(const std::string &value)` - Encodes a full URI, preserving reserved characters like `://`, `?`, `&`, `=`
- `decode_uri(const std::string &value)` - Decodes a URI-encoded string
- `encode_uri_component(const std::string &value)` - Encodes a URI component (query parameter, path segment), encoding all reserved characters
- `decode_uri(const std::string &value)` - Decodes a URI-encoded string, but leaves escapes of the reserved characters that `encode_uri()` preserves (e.g. `%2F`, `%3F`) as they are, like JavaScript's `decodeURI()`
- `encode_uri_component(const std::string &value)` - Encodes a URI component (query parameter, path segment), encoding all reserved characters except `!`, `*`, `'`, `(` and `)`, like JavaScript's `encodeURIComponent()`
- `decode_uri_component(const std::string &value)` - Decodes a URI component
Use `encode_uri()` for full URLs and `encode_uri_component()` for individual query parameters or path segments.
@@ -1663,6 +1743,8 @@ if (result2) {
All HTTP methods are supported: `stream::Get`, `Post`, `Put`, `Patch`, `Delete`, `Head`, `Options`.
Unlike a content receiver, the Stream API is bounded by the client's `set_payload_max_length()` (100MB by default). Reading past it stops with `read_error() == Error::ExceedMaxPayloadSize`.
See [README-stream.md](README-stream.md) for more details.
> svr.Get(R"(/api/v\d+/.*)", handler); // Regex route, limited to short paths
> ```
>
> The limit is no guarantee on a thread with a small stack, such as one of musl's 128KB threads, where a pattern like `(\w|-)+` can already overflow on a shorter path; lower the limit there. Nor does it bound the time a pattern with nested repetition, such as `((\w+-?)+)`, can take to fail on a few dozen characters. Keep regex routes simple.
Per-request headers are **added** on top of the defaults. Both are sent to the server.
Per-request headers are **added** on top of the defaults, and both are sent to the server. If a per-request header has the same name as a default one, only the per-request one is sent.
> For details on Bearer token auth, see [C06. Call an API with a Bearer token](../c06-bearer-token).
Many sites redirect HTTP traffic to HTTPS. With `set_follow_location(true)` on, this case is handled transparently — the client follows redirects even when the scheme or host changes.
When a redirect goes to another origin (a different scheme, host, or port), the client drops the `Authorization`, `Cookie`, and `Proxy-Authorization` headers, along with the credentials set with `set_basic_auth()` and the like, and doesn't present the client certificate. Other headers, default ones included, go along, and so do the timeouts, the payload limit, and the TLS verification settings.
> **Warning:** To follow redirects to HTTPS, you need to build cpp-httplib with OpenSSL (or another TLS backend). Without TLS support, redirects to HTTPS will fail.
> **Note:** Following redirects adds to the total request time. See [C12. Set timeouts](../c12-timeouts) for timeout configuration.
@@ -27,7 +27,7 @@ The `ContentProvider` reads the file in chunks, so even huge files never sit ful
## When the file can't be opened
If the file can't be opened, `make_file_body()` returns `size` as `0` and `provider` as an empty function object. Sending that would produce garbage — always check `size` first.
If the file can't be opened, `make_file_body()` returns `size` as `0` and `provider` as an empty function object. Sending that would upload an empty body — always check `provider` first. Checking `size` won't do: an empty file also gives `0`, with a working `provider`.
> **Warning:** `make_file_body()` needs to fix the Content-Length up front, so it reads the file size ahead of time. If the file size might change mid-upload, this API isn't the right fit.
The three timeouts from [C12. Set timeouts](../c12-timeouts) all apply to a single `send` or `recv` call. To cap the total time a request can take, use `set_max_timeout()`.
The three timeouts from [C12. Set timeouts](../c12-timeouts) each cover only one step: the read and write timeouts apply to a single `recv` or `send` call, and the connection timeout to connecting. To cap the total time a request can take, use `set_max_timeout()`.
With `set_compress(true)`, the body of POST or PUT requests is compressed before sending. The encoding is the first one enabled in your build, in the order Brotli, gzip, Zstd. The server needs to handle compressed bodies too.
With `set_compress(true)`, the body of POST, PUT, or PATCH requests is compressed before sending. The encoding is the first one enabled in your build, in the order Brotli, gzip, Zstd. The server needs to handle compressed bodies too.
The request goes through the proxy. For HTTPS, the client uses the CONNECT method to tunnel through — no extra setup required.
If the proxy refuses the tunnel, the request fails with `Error::ProxyConnection`. The exception is a 407: it comes back as the response, so `res` is truthy and `res->status` is 407, while `res.error()` still returns `Error::ProxyConnection`.
## Proxy authentication
If the proxy itself requires authentication, use `set_proxy_basic_auth()` or `set_proxy_bearer_token_auth()`.
@@ -69,6 +71,20 @@ Hostname matching is case-insensitive and uses a dot-boundary rule, so an entry
Malformed entries are silently dropped. Port-specific entries such as `example.com:8080` are not supported (cpp-httplib's other host-keyed APIs are also keyed on hostname only).
For both `ws://` and `wss://`, the client opens a tunnel with the CONNECT method and then performs the WebSocket handshake through it. `set_no_proxy()` works the same way.
## Read proxy settings from the environment
cpp-httplib doesn't touch `HTTP_PROXY` / `HTTPS_PROXY` / `NO_PROXY` on its own — the config API is always explicit, the same way `set_ca_cert_path()` is. If you'd like that behavior, read the variables in your application and feed them to `set_proxy()` and `set_no_proxy()`.
`cli.Get()`, `cli.Post()`, and friends return a `Result`. When the request fails — can't reach the server, times out, etc. — the result is "falsy". To get the specific reason, use `Result::error()`.
`cli.Get()`, `cli.Post()`, and friends return a `Result`. When the request fails — can't reach the server, times out, etc. — the result is "falsy", with one exception noted in the table below. To get the specific reason, use `Result::error()`.
## Basic check
@@ -27,14 +27,16 @@ Use `if (res)` to check success. On failure, `res.error()` returns a `httplib::E
| Value | Meaning |
| --- | --- |
| `Error::Connection` | Couldn't connect to the server |
| `Error::Connection` | Couldn't connect to the server, or the `Client` was built from a URL it can't use (userinfo or a backslash in the authority, a bad port). In the latter case `cli.is_valid()` is `false` |
| `Error::Read` / `Error::Write` | Error during send or receive. A timeout from `set_read_timeout` or `set_max_timeout` is also reported as `Error::Read` |
| `Error::ExceedMaxPayloadSize` | The response body is larger than `set_payload_max_length()` allows, also once decompressed |
| `Error::Timeout` | A body read timed out in `stream::Get()` or `SSEClient` |
| `Error::ExceedRedirectCount` | Too many redirects |
| `Error::SSLConnection` | TLS handshake failed |
| `Error::SSLServerVerification` | Server certificate verification failed |
| `Error::Canceled` | A progress callback returned `false` |
| `Error::ProxyConnection` | The proxy refused the CONNECT tunnel. A 407 is the exception: `res` is truthy with `res->status == 407`, and `res.error()` is still `Error::ProxyConnection` |
| `Error::Canceled` | A progress callback, a `ContentReceiver`, a `ResponseHandler`, or an upload content provider returned `false` |
`ssl_error()` is a backend-independent TLS error category: an `httplib::tls::ErrorCode` cast to `int`. `ssl_backend_error()` gives you the backend's own error value. With OpenSSL that is `ERR_get_error()` when the handshake failed, and the verify result (`X509_V_ERR_*`) when certificate verification failed.
`ssl_error()` is a backend-independent TLS error category: an `httplib::tls::ErrorCode` cast to `int`. `ssl_backend_error()` gives you the backend's own error value. With OpenSSL that is `ERR_get_error()` when the handshake or a later read or write failed, and the verify result (`X509_V_ERR_*`) when certificate verification failed.
A request that fails after the handshake reports `Error::Read` or `Error::Write`. Even then, `ssl_error()` and `ssl_backend_error()` carry the TLS error behind it. For example, if the server requires a client certificate you didn't send, OpenSSL's error reads "tlsv13 alert certificate required". Both values are reset for each request and are `0` when no TLS error was involved.
The second argument `req` can be null — it happens when the failure occurred before the request was built. Always null-check before dereferencing.
Each failed request is reported once, with the request you made, also when it failed on a redirect. A stream that fails to open with `open_stream()` or `stream::Get()` is reported the same way; errors while reading its body come back through `read_error()` instead. `req` is null only in a server's error logger, for errors that belong to no request.
Hook into connection open and error events. Even when the error handler fires, `SSEClient` keeps trying to reconnect in the background. The exceptions are a 204, 403, or 404 response, after which it stops.
Hook into connection open and error events. Even when the error handler fires, `SSEClient` keeps trying to reconnect in the background. It stops after a 204, 403, or 404 response, or once the attempts set with `set_max_reconnect_attempts()` run out.
It also stops when an event, or a line still waiting for its end, grows past `CPPHTTPLIB_SSE_MAX_EVENT_LENGTH` (16MB by default, 0 for no limit). The error handler then gets `Error::ExceedMaxPayloadSize`. The client's `set_payload_max_length()` doesn't apply to the stream as a whole, since an event stream has no end.
## Run asynchronously
@@ -88,6 +90,8 @@ If the server sends a `retry:` field, that takes precedence.
`SSEClient` tracks the `id` of each received event internally and sends it back as `Last-Event-ID` on reconnect. As long as the server sends events with `id:`, this all works automatically.
An empty `id:` clears the stored id. An `id:` that can't be sent as a header value (one with NUL or other control characters, or with leading or trailing whitespace) is ignored, and the previous id stays.
Parentheses in the pattern become captures in `req.matches`. `req.matches[0]` is the full match; `req.matches[1]` onward are the captures.
A regex route isn't applied to a path longer than `CPPHTTPLIB_REGEX_ROUTE_PATH_MAX_LENGTH` (256 by default); such a path is treated as no match. This keeps `std::regex` from overflowing the stack on long input. If your routes need longer paths, define the macro with a larger value.
## Which to use
- For plain IDs or slugs, `:name` is enough — readable, and the shape is obvious
@@ -10,12 +10,19 @@ To serve static files like HTML, CSS, and images, use `set_mount_point()`. Just
```cpp
httplib::Serversvr;
svr.set_mount_point("/","./public");
if(!svr.set_mount_point("/","./public")){
// ./public doesn't exist
return1;
}
svr.listen("0.0.0.0",8080);
```
`set_mount_point()` returns `false` when the directory doesn't exist, so check the return value.
`./public/index.html` is now reachable at `http://localhost:8080/index.html`, and `./public/css/style.css` at `http://localhost:8080/css/style.css`. The directory layout maps directly to URLs.
A request for a directory serves its `index.html`, and one without the trailing slash (`/docs`) is redirected (301) to `/docs/`. A symlink that resolves outside the mounted directory gets a 403.
if(name.empty()){returnfalse;}// reject an unsafe name
ofs.open("uploads/"+name,std::ios::binary);
returnofs.is_open();
},
[&](constchar*data,size_tlen){
if(!ofs.is_open()){returntrue;}// not part of a file
ofs.write(data,len);
returnstatic_cast<bool>(ofs);
});
if(!ok){return;}// the status is already set
res.set_content("uploaded","text/plain");
});
```
The header callback runs at the start of every part, so it closes the previous file before opening the next one. `file.filename` is whatever the client sent, so always pass it through `httplib::sanitize_filename()`. An empty result means the name is unsafe.
Only a small chunk sits in memory at any moment, so gigabyte-scale files are no problem.
Handler responses, buffered or streamed, are then sent as they are. Over HTTPS, the length of a compressed response can give away a secret in it, such as a CSRF token, when the same response also carries text an attacker can choose (the BREACH attack). Static file compression is set separately.
## Static files need to be opted in
Files served as they are, through `set_mount_point()` or `Response::set_file_content()`, are not compressed by default. Turn it on with:
The pre-routing handler runs **before routing**. It catches every request — including ones that don't match any handler.
The pre-routing handler runs **before routing**. It catches every request — including ones that don't match any handler. The exception is a request rejected while its request line and headers are parsed (400 for a malformed request, 414 for an overlong URI, 416 for a malformed `Range`); the server answers those before this handler runs.
@@ -38,6 +38,8 @@ svr.Options("/.*", [](const auto &req, auto &res) {
});
```
`/.*` is a regex route, so it isn't applied to paths longer than `CPPHTTPLIB_REGEX_ROUTE_PATH_MAX_LENGTH` (256 by default). If your paths can be longer, handle `OPTIONS` in the pre-routing handler instead.
@@ -17,6 +17,8 @@ In a pre-request handler, `req.matched_route` holds the **pattern string** that
Because the body has not been read when the pre-request handler runs, you can reject a request — for example on a failed auth check — without consuming a (potentially large) request body. Note that this also means `req.body` and form fields parsed from the body are not available here; inspect headers, the path, query parameters, or `req.matched_route` instead.
The pre-request handler runs only for requests that match a route. Files served by `set_mount_point()` are answered before route matching, so guard static files in the pre-routing handler.
## Switch auth per route
```cpp
@@ -39,6 +41,8 @@ svr.set_pre_request_handler(
The pre-request handler also runs for routes registered with `svr.WebSocket()`. It is called before the `101 Switching Protocols` response, so returning `Handled` sends your HTTP response (such as a 403) and the connection is never upgraded.
The server accepts a handshake from any `Origin`. A browser sends its cookies even with a handshake that another site starts, so if cookies authenticate the connection, also check `req.get_header_value("Origin")` against your own origins here.
To customize the response for 4xx or 5xx errors, use `set_error_handler()`. You can replace the plain default error page with your own HTML or JSON.
To customize the response for 4xx or 5xx errors, use `set_error_handler()`. By default, an error response has an empty body; an error handler lets you fill it with your own HTML or JSON.
To log the requests the server receives and the responses it returns, use `Server::set_logger()`. The callback fires once per completed request, making it the foundation for access logs and metrics collection.
To log the requests the server receives and the responses it returns, use `Server::set_logger()`. The callback fires once per request, right before the response is written, making it the foundation for access logs and metrics collection.
The log callback receives both the `Request` and the `Response`. You can grab the method, path, status, client IP, headers, body — whatever you need.
`req.path` is percent-decoded, so it may contain control characters such as CR/LF. Escape it before writing it to a log file, or a crafted request can forge log lines.
## Access-log style format
Here's an Apache/Nginx-ish access log format.
@@ -38,6 +40,8 @@ svr.set_logger([](const auto &req, const auto &res) {
});
```
For a response sent through a content provider, such as a file served from a mount point, `res.body` is empty here, so the size shows `0B`.
## Measure request time
To include request duration in the log, stash a start timestamp in `res.user_data` from a pre-routing handler, then subtract in the logger.
Since the logger runs before the response is written, the time doesn't include sending the body.
For more on `user_data`, see [S12. Pass data between handlers with `res.user_data`](../s12-user-data).
> **Note:** The logger runs synchronously on the same thread as request processing. Heavy work inside it hurts throughput — push it to a queue and process asynchronously if you need anything expensive.
> **Note:** The logger runs synchronously on the same thread as request processing, and all logger calls on a server share one lock. Heavy work inside it hurts throughput — push it to a queue and process asynchronously if you need anything expensive.
When you call `stop()`, new connections are refused, but handlers that are already running are **allowed to finish**. A response still being sent by a content provider (a streaming response, for example) is cut short, though. Once all workers drain, `listen()` returns. That's what makes it graceful.
> **Warning:** There's a wait between calling `stop()` and `listen()` returning — it's the time in-flight requests take to finish. To enforce a timeout, you'll need to add your own shutdown timer in application code.
> **Note:** `stop()` doesn't interrupt WebSocket handlers. A handler looping on `read()` keeps running as long as its peer stays connected, and `listen()` doesn't return until it ends. Keep track of open WebSocket connections and `close()` them on shutdown, e.g. with `CloseStatus::GoingAway`.
| `set_keep_alive_max_count` | 100 | Max requests served over a single connection |
| `set_keep_alive_max_count` | 100 | Max requests served over a single connection (0 for no limit) |
| `set_keep_alive_timeout` | 5s | How long an idle connection is kept before closing |
## Basic usage
@@ -52,6 +52,6 @@ Set `set_keep_alive_max_count(1)` and every request gets its own connection. Mos
## Relationship with the thread pool
A Keep-Alive connection holds a worker thread for its entire lifetime. If `connections × concurrent requests` exceeds the thread pool size, new requests wait. For thread counts, see [S21. Configure the thread pool](../s21-thread-pool).
A Keep-Alive connection holds a worker thread for its entire lifetime. The pool adds threads under load, up to its maximum thread count (4× the base count by default). If open connections outnumber that maximum, new connections wait in the queue until one closes. For thread counts, see [S21. Configure the thread pool](../s21-thread-pool).
> **Note:** For the client side, see [C14. Understand connection reuse and Keep-Alive behavior](../c14-keep-alive). Even when the server closes the connection on timeout, the client reconnects automatically.
@@ -66,4 +66,4 @@ You can set the defaults with macros if you want compile-time configuration.
#include<httplib.h>
```
> **Note:** A WebSocket connection holds a worker thread for its entire lifetime. For lots of simultaneous WebSocket connections, enable dynamic scaling (e.g. `ThreadPool(8, 64)`).
> **Note:** A WebSocket connection holds a worker thread for its entire lifetime. For lots of simultaneous WebSocket connections, raise the maximum thread count (e.g. `ThreadPool(8, 64)`).
@@ -46,4 +46,4 @@ Certificate verification control, standing up an SSLServer, reading the peer cer
- [T03. Start an SSL/TLS server](../t03-ssl-server)
- [T05. Access the peer certificate on the server](../t05-peer-cert)
> **Note:** On macOS with an OpenSSL-family backend, cpp-httplib automatically loads root certificates from the system keychain (via `CPPHTTPLIB_USE_CERTS_FROM_MACOSX_KEYCHAIN`, on by default). To disable this, define `CPPHTTPLIB_DISABLE_MACOSX_AUTOMATIC_ROOT_CERTIFICATES`.
> **Note:** On macOS, with any of the three backends, cpp-httplib automatically loads root certificates from the system keychain (via `CPPHTTPLIB_USE_CERTS_FROM_MACOSX_KEYCHAIN`, on by default). To disable this, define `CPPHTTPLIB_DISABLE_MACOSX_AUTOMATIC_ROOT_CERTIFICATES`.
The first argument is the CA certificate file; the second is an optional CA directory. With the OpenSSL backend, you can also pass an `X509_STORE*` directly via `set_ca_cert_store()`.
Once you set a custom CA, the client trusts only that CA and skips the OS store. To trust both, also call `cli.enable_system_ca(true)`. CA certificates are loaded once, on the client's first connection, so make these settings before the first request.
For development servers or self-signed certificates, you can skip verification entirely.
@@ -46,7 +48,7 @@ The certificate itself is still validated, so this is safer than fully disabling
## Use the OS cert store as-is
On most Linux distributions, root certificates live in a single file like `/etc/ssl/certs/ca-certificates.crt`. cpp-httplib reads the OS default store at startup, so for most servers you don't need to configure anything.
On most Linux distributions, root certificates live in a single file like `/etc/ssl/certs/ca-certificates.crt`. cpp-httplib loads the OS default store on the client's first connection, so for most servers you don't need to configure anything.
> The same APIs work on the mbedTLS and wolfSSL backends. For choosing between backends, see [T01. Choosing between OpenSSL, mbedTLS, and wolfSSL](../t01-tls-backends).
@@ -60,7 +60,7 @@ Before a certificate expires, you may want to swap it out without restarting the
svr.update_certs_pem(new_cert_pem,new_key_pem);
```
Existing connections keep using the old cert; new connections use the new one.
Existing connections keep using the old cert; new connections use the new one. It waits for handshakes in progress to finish, at most the read timeout, and new connections wait until it returns. So don't call it from a TLS callback that runs during a handshake: it would wait for that handshake.
There's also a helper to check if a hostname is covered by the SAN list:
There's also a helper that checks whether the certificate covers a hostname. It follows the rules of TLS hostname verification: an IP address is matched against the IP address SANs, a name against the DNS SANs, and the CN is used only when there's no DNS SAN.
@@ -81,7 +81,7 @@ Combined with a pre-request handler, you can keep all authorization logic in one
## SNI (Server Name Indication)
cpp-httplib handles SNI automatically. If one server hosts multiple domains, SNI is used under the hood — but normally handlers don't need to care.
Clients send SNI automatically. On the server, `req.sni()` returns the name the client asked for. `SSLServer` presents the same certificate whatever that name is, though, so to host several domains on one server, use a certificate that covers all of them. To choose a certificate per name, hook into the TLS backend yourself — with OpenSSL, for example, set a servername callback through the `SSLServer` constructor that takes a context setup callback.
> **Warning:** `req.peer_cert()` only returns a meaningful value when mTLS is enabled and the client actually presented a certificate. For plain TLS, you get an empty `PeerCert`. Always do the `bool` check before using it.
// echo back what we received, in the same frame type
if(result==httplib::ws::ReadResult::Binary){
ws.send(msg.data(),msg.size());
}else{
ws.send(msg);
}
}
});
@@ -29,7 +34,7 @@ int main() {
}
```
Register a WebSocket handler with `svr.WebSocket()`. By the time the handler runs, the WebSocket handshake is already complete. Inside the loop, just `ws.read()` and `ws.send()` to get a working echo.
Register a WebSocket handler with `svr.WebSocket()`. By the time the handler runs, the WebSocket handshake is already complete. Inside the loop, just `ws.read()` and `ws.send()` to get a working echo. A binary message goes back through the `data()` + `size()` overload so it stays binary (more on that below).
The `read()` return value is a `ReadResult` enum:
@@ -76,7 +81,7 @@ The `std::string` overload sends as **text**; the `const char*` + size overload
## Thread pool implications
A WebSocket handler holds its worker thread for the entire life of the connection — one connection per thread. For many concurrent clients, configure a dynamic thread pool.
A WebSocket handler holds its worker thread for the entire life of the connection — one connection per thread. The default pool already grows under load, up to 4× its base thread count. For many concurrent clients, raise that maximum.
@@ -43,7 +43,7 @@ The default interval is set by the build-time macro `CPPHTTPLIB_WEBSOCKET_PING_I
## What about Pong?
The WebSocket protocol requires that Ping frames are answered with Pong frames. cpp-httplib responds to Pings automatically — you don't need to think about it in application code.
The WebSocket protocol requires that Ping frames are answered with Pong frames. cpp-httplib answers Pings automatically inside `read()` — as long as your code keeps calling `read()`, you don't need to think about it.
The client can inspect that status and decide whether to reconnect.
On the client, `read()` just returns `Fail`; the status and reason it received aren't exposed. If the client needs to tell a restart from other closures, send it a message first (say, `ws.send("restarting")`), then call `close()`.
@@ -85,4 +85,4 @@ if (cli.read(buf) == httplib::ws::ReadResult::Binary) {
You can mix text and binary in the same connection. A common pattern: JSON for control messages, binary for the actual data — you get efficient handling of metadata and payload both.
> **Note:** WebSocket frames don't have an infinite size limit. For very large data, chunk it in your application code. cpp-httplib can handle a big frame in one shot, but it does load it all into memory at once.
> **Note:** An incoming message can be at most `CPPHTTPLIB_WEBSOCKET_MAX_PAYLOAD_LENGTH` (16MB by default, 0 for no limit). A larger one makes `read()` return `Fail` and ends the connection. Within that limit, a message is held in memory whole, so for very large data, chunk it in your application code.
To disable certificate verification entirely, use `enable_server_certificate_verification(false)`. For details on that behavior, see [T02. Control SSL Certificate Verification](../t02-cert-verification).
`WebSocketClient` also has `set_server_certificate_verifier()` and `set_session_verifier()` for custom checks, plus the proxy setters (`set_proxy()`, `set_proxy_basic_auth()`, `set_proxy_bearer_token_auth()`, `set_proxy_digest_auth()`, `set_no_proxy()`). CA certificates are loaded on the first `connect()`, so set them before that.
## Presenting a client certificate (mTLS)
`ws::WebSocketClient` has a constructor overload that takes a `PemMemory` struct, letting `wss://` connections present a client certificate.
@@ -9,7 +9,7 @@ When you need a quick HTTP server or client in C++, you want something that just
The API uses a lambda-based design that feels natural. It runs anywhere you have a C++11 or later compiler. Windows, macOS, Linux — use whatever environment you already have.
HTTPS works too. Just link OpenSSL or mbedTLS, and both server and client gain TLS support. Content-Encoding (gzip, Brotli, etc.), file uploads, and other features you actually need in real-world development are all included. WebSocket is also supported.
HTTPS works too. Just link OpenSSL, MbedTLS, or wolfSSL, and both server and client gain TLS support. Content-Encoding (gzip, Brotli, etc.), file uploads, and other features you actually need in real-world development are all included. WebSocket is also supported.
Under the hood, it uses blocking I/O with a thread pool. It's not built for handling massive numbers of simultaneous connections. But for API servers, embedded HTTP in tools, mock servers for testing, and many other use cases, it delivers solid performance.
@@ -59,7 +59,7 @@ Compatibility with existing tools and libraries is a big design decision. We des
## 7.3 Concurrent Request Handling
Our server processes requests one at a time. If another request arrives while a translation is in progress, it waits until the previous inference finishes. This is fine for a desktop app used by one person, but it becomes a problem for a server shared by multiple users.
Our server runs inference one request at a time. If another request arrives while a translation is in progress, it waits until the previous inference finishes. This is fine for a desktop app used by one person, but it becomes a problem for a server shared by multiple users.
`llama-server` handles concurrent requests through a mechanism called **slots**.
@@ -67,7 +67,7 @@ Our server processes requests one at a time. If another request arrives while a
The key point is that tokens from each slot are not inferred **one by one in sequence**, but rather **all at once in a single batch**. GPUs excel at parallel processing, so processing two users simultaneously takes almost the same time as processing one. This is called "continuous batching."
In our server, cpp-httplib's thread pool assigns one thread per request, but the inference itself runs single-threaded inside `llm.chat()`. `llama-server` consolidates this inference step into a shared batch processing loop.
In our server, cpp-httplib's thread pool serves each connection on its own worker thread, so requests on different connections are handled concurrently. Inference, however, is serialized by `llm_mutex`, so only one `llm.chat()` runs at a time. `llama-server` consolidates this inference step into a shared batch processing loop.
You can also pass a `content_receiver` callback to`Get()`. This approach works with Keep-Alive.
Note that `stream::Get()` reads no more of the body than the client's`set_payload_max_length()` allows, which is 100MB by default. For larger downloads, raise it, or set it to 0 for no limit.
You can also pass a `content_receiver` callback to `Get()`. This approach works with Keep-Alive, and it has no size limit unless you set one with `set_payload_max_length()`.
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