Add server_mount_fuzzer for static file serving (#2666)

Fuzz Server::handle_file_request through a mount point backed by a temporary directory that holds symlinks escaping the mount root, one of them into a sibling directory sharing its name prefix. Abort if a token stored outside the root appears in a response. The seeds are based on those of #2661.

Move FuzzedStream into fuzzed_stream.h so that both server fuzzers share it, and add FuzzableServer::MarkAsRunning(), without which a server that is not listening writes no file.

README.md

@@ -1716,6 +1716,8 @@ cli.set_address_family(AF_UNIX);
 
 This library automatically sets the Host header to "localhost" for Unix socket connections, similar to curl's behavior.
 
+With `set_follow_location(true)`, a redirect is followed over the same socket, whatever host the `Location` names, as curl's `--unix-socket` does. A host mapped with `set_direct_hostname_addr_map` goes to its mapped socket instead. Only a `Location` naming `localhost` counts as the same host; any other host is treated as cross-host, so `Authorization` and `Cookie` are not sent to it.
+
 
 URI Encoding/Decoding Utilities
 -------------------------------

docs-src/config.toml

@@ -4,7 +4,7 @@ langs = ["en", "ja"]
 
 [site]
 title = "cpp-httplib"
-version = "0.64.0"
+version = "0.66.0"
 hostname = "https://yhirose.github.io"
 base_path = "/cpp-httplib"
 footer_message = "© 2026 Yuji Hirose. All rights reserved."

httplib.h

@@ -8,8 +8,8 @@
 #ifndef CPPHTTPLIB_HTTPLIB_H
 #define CPPHTTPLIB_HTTPLIB_H
 
-#define CPPHTTPLIB_VERSION "0.64.0"
-#define CPPHTTPLIB_VERSION_NUM "0x004000"
+#define CPPHTTPLIB_VERSION "0.66.0"
+#define CPPHTTPLIB_VERSION_NUM "0x004200"
 
 #ifdef _WIN32
 #if defined(_WIN32_WINNT) && _WIN32_WINNT < 0x0A00
@@ -1029,18 +1029,27 @@ inline std::string resolve_relative_location(const std::string &location,
   // A ':' in the first segment means the value has a scheme.
   if (location.find(':') < location.find_first_of("/?#")) { return location; }
 
-  if (location[0] == '#') { return base.substr(0, base.find('#')) + location; }
+  // A path starting with "//" would be re-parsed as an authority. Prefix "/."
+  // (as the URL Standard does); remove_dot_segments strips it later.
+  auto on_this_host = [](std::string path) -> std::string {
+    if (path.compare(0, 2, "//") == 0) { path.insert(0, "/."); }
+    return path;
+  };
+
+  if (location[0] == '#') {
+    return on_this_host(base.substr(0, base.find('#')) + location);
+  }
 
   auto base_path = base.substr(0, base.find_first_of("?#"));
-  if (location[0] == '?') { return base_path + location; }
+  if (location[0] == '?') { return on_this_host(base_path + location); }
 
   if (base_path.empty() || base_path[0] != '/') { base_path = "/"; }
   auto merged = base_path.substr(0, base_path.rfind('/') + 1) + location;
 
   // Remove "." and ".." segments from the merged path.
   auto path_end = (std::min)(merged.find_first_of("?#"), merged.size());
-  return remove_dot_segments(merged.substr(0, path_end)) +
-         merged.substr(path_end);
+  return on_this_host(remove_dot_segments(merged.substr(0, path_end)) +
+                      merged.substr(path_end));
 }
 
 } // namespace detail
@@ -1335,7 +1344,7 @@ public:
   size_type erase(const std::string &key) {
     auto before = entries_.size();
     entries_.erase(std::remove_if(entries_.begin(), entries_.end(),
-                                  [&](const value_type &entry) {
+                                  [key](const value_type &entry) {
                                     return keys_equal(entry.first, key);
                                   }),
                    entries_.end());
@@ -3058,6 +3067,10 @@ protected:
   bool socket_should_be_closed_when_request_is_done_ = false;
   size_t socket_tls_settings_version_ = 0;
 
+  // Set by stop() while a request is in flight. The request's reads poll it,
+  // because shutting the socket down does not wake a read on Windows.
+  std::atomic<bool> stop_requested_{false};
+
   std::atomic<size_t> tls_settings_version_{0};
 
   // Hostname to connection target map. The value is an IP literal or another
@@ -4529,8 +4542,6 @@ public:
   void stop();
 
 private:
-  bool parse_sse_line(const std::string &line, SSEMessage &msg, int &retry_ms,
-                      bool &has_data, bool &has_id);
   void run_event_loop();
   void dispatch_event(const SSEMessage &msg);
   bool should_reconnect(int count) const;
@@ -4565,6 +4576,40 @@ private:
 
 } // namespace sse
 
+namespace detail {
+
+// Interprets an event stream fed in chunks of any size
+class SSEParser {
+public:
+  using EventHandler = std::function<void(const sse::SSEMessage &msg)>;
+  using IdHandler = std::function<void(const std::string &id)>;
+  using RetryHandler = std::function<void(int retry_ms)>;
+
+  SSEParser(EventHandler on_event, IdHandler on_id, RetryHandler on_retry,
+            size_t max_event_length = CPPHTTPLIB_SSE_MAX_EVENT_LENGTH);
+
+  // Returns false once the line and the event still waiting for their end
+  // exceed max_event_length. 0 means no limit.
+  bool parse(const char *buf, size_t n);
+
+private:
+  void parse_line(const std::string &line);
+
+  EventHandler on_event_;
+  IdHandler on_id_;
+  RetryHandler on_retry_;
+  size_t max_event_length_;
+
+  std::string buffer_;
+  sse::SSEMessage msg_;
+  bool has_data_ = false;
+  bool has_id_ = false;
+  bool first_line_ = true;
+  bool after_cr_ = false;
+};
+
+} // namespace detail
+
 namespace ws {
 
 class WebSocketClient;
@@ -5010,6 +5055,110 @@ inline std::string Result::read_all() {
 
 } // namespace stream
 
+namespace detail {
+
+inline SSEParser::SSEParser(EventHandler on_event, IdHandler on_id,
+                            RetryHandler on_retry, size_t max_event_length)
+    : on_event_(std::move(on_event)), on_id_(std::move(on_id)),
+      on_retry_(std::move(on_retry)), max_event_length_(max_event_length) {}
+
+inline bool SSEParser::parse(const char *buf, size_t n) {
+  // What is left in the buffer has no line ending
+  auto search_pos = buffer_.size();
+  buffer_.append(buf, n);
+
+  // A line ends with \r\n, \n or \r per the SSE spec
+  size_t line_start = 0;
+  size_t eol_pos;
+
+  while ((eol_pos = buffer_.find_first_of("\r\n", search_pos)) !=
+         std::string::npos) {
+    auto line = buffer_.substr(line_start, eol_pos - line_start);
+    line_start = eol_pos + 1;
+    search_pos = line_start;
+
+    // The \n of a \r\n may arrive in a later chunk than its \r
+    auto is_lf_of_crlf = after_cr_ && line.empty() && buffer_[eol_pos] == '\n';
+    after_cr_ = buffer_[eol_pos] == '\r';
+    if (is_lf_of_crlf) { continue; }
+
+    // A UTF-8 BOM at the start of the stream is ignored per the SSE spec
+    if (first_line_) {
+      first_line_ = false;
+      if (line.compare(0, 3, "\xEF\xBB\xBF") == 0) { line.erase(0, 3); }
+    }
+
+    parse_line(line);
+  }
+
+  // Keep unprocessed data in buffer
+  buffer_.erase(0, line_start);
+
+  return max_event_length_ == 0 ||
+         buffer_.size() + msg_.data.size() <= max_event_length_;
+}
+
+inline void SSEParser::parse_line(const std::string &line) {
+  // Blank line signals end of event
+  if (line.empty()) {
+    // The id counts for Last-Event-ID even for an event that has no data. An
+    // empty id clears it.
+    if (has_id_ && on_id_) { on_id_(msg_.id); }
+
+    // An event without a data field is not dispatched
+    if (has_data_ && on_event_) { on_event_(msg_); }
+
+    msg_.clear();
+    has_data_ = false;
+    has_id_ = false;
+    return;
+  }
+
+  // Lines starting with ':' are comments (ignored)
+  if (line[0] == ':') { return; }
+
+  // Find the colon separator
+  auto colon_pos = line.find(':');
+  auto field = line.substr(0, colon_pos);
+  std::string value;
+
+  // Value starts after colon, skip optional single space
+  if (colon_pos != std::string::npos && colon_pos + 1 < line.size()) {
+    auto value_start = colon_pos + 1;
+    if (line[value_start] == ' ') { value_start++; }
+    value = line.substr(value_start);
+  }
+
+  // Handle known fields
+  if (field == "event") {
+    // An empty event type is dispatched as "message" per the SSE spec
+    msg_.event = value.empty() ? std::string("message") : std::move(value);
+  } else if (field == "data") {
+    // Multiple data lines are concatenated with newlines
+    if (has_data_) { msg_.data += "\n"; }
+    msg_.data += value;
+    has_data_ = true;
+  } else if (field == "id") {
+    // An id that cannot be sent back as Last-Event-ID is ignored. Empty id is
+    // valid (clears the last event ID)
+    if (fields::is_field_value(value)) {
+      msg_.id = value;
+      has_id_ = true;
+    }
+  } else if (field == "retry") {
+    // Parse retry interval in milliseconds
+    // Per the SSE spec, a value that is not all ASCII digits is ignored.
+    if (is_numeric(value)) {
+      int v = 0;
+      auto res = from_chars(value.data(), value.data() + value.size(), v);
+      if (res.ec == std::errc{} && on_retry_) { on_retry_(v); }
+    }
+  }
+  // Unknown fields are ignored per SSE spec
+}
+
+} // namespace detail
+
 namespace sse {
 
 // SSEMessage implementations
@@ -5091,58 +5240,6 @@ inline void SSEClient::stop() {
   if (async_thread_.joinable()) { async_thread_.join(); }
 }
 
-inline bool SSEClient::parse_sse_line(const std::string &line, SSEMessage &msg,
-                                      int &retry_ms, bool &has_data,
-                                      bool &has_id) {
-  // Blank line signals end of event
-  if (line.empty()) { return true; }
-
-  // Lines starting with ':' are comments (ignored)
-  if (line[0] == ':') { return false; }
-
-  // Find the colon separator
-  auto colon_pos = line.find(':');
-  auto field = line.substr(0, colon_pos);
-  std::string value;
-
-  // Value starts after colon, skip optional single space
-  if (colon_pos != std::string::npos && colon_pos + 1 < line.size()) {
-    auto value_start = colon_pos + 1;
-    if (line[value_start] == ' ') { value_start++; }
-    value = line.substr(value_start);
-  }
-
-  // Handle known fields
-  if (field == "event") {
-    // An empty event type is dispatched as "message" per the SSE spec
-    msg.event = value.empty() ? std::string("message") : std::move(value);
-  } else if (field == "data") {
-    // Multiple data lines are concatenated with newlines
-    if (has_data) { msg.data += "\n"; }
-    msg.data += value;
-    has_data = true;
-  } else if (field == "id") {
-    // An id that cannot be sent back as Last-Event-ID is ignored. Empty id is
-    // valid (clears the last event ID)
-    if (detail::fields::is_field_value(value)) {
-      msg.id = value;
-      has_id = true;
-    }
-  } else if (field == "retry") {
-    // Parse retry interval in milliseconds
-    // Per the SSE spec, a value that is not all ASCII digits is ignored.
-    if (detail::is_numeric(value)) {
-      int v = 0;
-      auto res =
-          detail::from_chars(value.data(), value.data() + value.size(), v);
-      if (res.ec == std::errc{}) { retry_ms = v; }
-    }
-  }
-  // Unknown fields are ignored per SSE spec
-
-  return false;
-}
-
 inline void SSEClient::run_event_loop() {
   auto reconnect_count = 0;
 
@@ -5203,72 +5300,17 @@ inline void SSEClient::run_event_loop() {
     if (on_open_) { on_open_(); }
 
     // Event receiving loop
-    std::string buffer;
-    SSEMessage current_msg;
-    auto has_data = false;
-    auto has_id = false;
-    auto first_line = true;
-    auto after_cr = false;
+    detail::SSEParser parser(
+        [this](const SSEMessage &msg) { dispatch_event(msg); },
+        [this](const std::string &id) {
+          std::lock_guard<std::mutex> lock(last_event_id_mutex_);
+          last_event_id_ = id;
+        },
+        [this](int retry_ms) { reconnect_interval_ms_ = retry_ms; });
     auto event_too_long = false;
 
     while (running_.load() && result.next()) {
-      // What is left in the buffer has no line ending
-      auto search_pos = buffer.size();
-      buffer.append(result.data(), result.size());
-
-      // Process complete lines in the buffer. A line ends with \r\n, \n or \r
-      // per the SSE spec
-      size_t line_start = 0;
-      size_t eol_pos;
-
-      while ((eol_pos = buffer.find_first_of("\r\n", search_pos)) !=
-             std::string::npos) {
-        auto line = buffer.substr(line_start, eol_pos - line_start);
-        line_start = eol_pos + 1;
-        search_pos = line_start;
-
-        // The \n of a \r\n may arrive in a later chunk than its \r
-        auto is_lf_of_crlf =
-            after_cr && line.empty() && buffer[eol_pos] == '\n';
-        after_cr = buffer[eol_pos] == '\r';
-        if (is_lf_of_crlf) { continue; }
-
-        // A UTF-8 BOM at the start of the stream is ignored per the SSE spec
-        if (first_line) {
-          first_line = false;
-          if (line.compare(0, 3, "\xEF\xBB\xBF") == 0) { line.erase(0, 3); }
-        }
-
-        // Parse the line and check if event is complete
-        auto event_complete = parse_sse_line(
-            line, current_msg, reconnect_interval_ms_, has_data, has_id);
-
-        if (event_complete) {
-          // Update last_event_id for reconnection, even for an event that
-          // has no data. An empty id clears it.
-          if (has_id) {
-            std::lock_guard<std::mutex> lock(last_event_id_mutex_);
-            last_event_id_ = current_msg.id;
-          }
-
-          // An event without a data field is not dispatched
-          if (has_data) { dispatch_event(current_msg); }
-
-          // Reset the message for the next event either way
-          current_msg.clear();
-          has_data = false;
-          has_id = false;
-        }
-      }
-
-      // Keep unprocessed data in buffer
-      buffer.erase(0, line_start);
-
-      // Neither an event nor a line still waiting for its end may grow
-      // without bound. 0 means no limit.
-      if (CPPHTTPLIB_SSE_MAX_EVENT_LENGTH > 0 &&
-          buffer.size() + current_msg.data.size() >
-              CPPHTTPLIB_SSE_MAX_EVENT_LENGTH) {
+      if (!parser.parse(result.data(), result.size())) {
         if (on_error_) { on_error_(Error::ExceedMaxPayloadSize); }
         event_too_long = true;
         break;
@@ -6840,10 +6882,14 @@ select_read_interruptible(socket_t sock, time_t sec, time_t usec,
   while (!interrupted()) {
     auto left = std::chrono::duration_cast<std::chrono::microseconds>(
         deadline - std::chrono::steady_clock::now());
-    auto wait =
-        (std::max)((std::min)(left, slice), std::chrono::microseconds(0));
-    auto ret = select_impl(sock, POLLIN, 0, static_cast<time_t>(wait.count()));
-    if (ret != 0 || wait < slice) { return ret; }
+    auto last = left < slice;
+    // poll() takes whole milliseconds, so round the last wait up to keep it
+    // from ending before the deadline.
+    auto wait_usec = last ? (std::max)((left.count() + 999) / 1000 * 1000,
+                                       static_cast<decltype(left.count())>(0))
+                          : slice.count();
+    auto ret = select_impl(sock, POLLIN, 0, static_cast<time_t>(wait_usec));
+    if (ret != 0 || last) { return ret; }
   }
   return 0;
 }
@@ -9335,6 +9381,7 @@ inline bool redirect(T &cli, Request &req, Response &res,
                      Error &error) {
   Request new_req = req;
   new_req.path = path;
+  new_req.params.clear();
   new_req.redirect_count_ -= 1;
 
   if (res.status == StatusCode::SeeOther_303 &&
@@ -12620,7 +12667,16 @@ inline bool ThreadPool::enqueue(std::function<void()> fn) {
     if (jobs_.size() > idle_thread_count_ &&
         threads_.size() + dynamic_threads_.size() < max_thread_count_) {
       cleanup_finished_threads();
-      dynamic_threads_.emplace_back(std::thread([this]() { worker(true); }));
+#ifndef CPPHTTPLIB_NO_EXCEPTIONS
+      try {
+#endif
+        dynamic_threads_.emplace_back(std::thread([this]() { worker(true); }));
+#ifndef CPPHTTPLIB_NO_EXCEPTIONS
+      } catch (const std::system_error &) {
+        // No thread budget left: keep the job queued for an existing worker
+        // instead of letting the exception escape the accept loop.
+      }
+#endif
     }
   }
 
@@ -12859,7 +12915,8 @@ inline ssize_t SocketStream::read(char *ptr, size_t size) {
 inline ssize_t SocketStream::write(const char *ptr, size_t size) {
   if (!wait_writable()) { return -1; }
 
-#if defined(_WIN32) && !defined(_WIN64)
+  // Winsock's send() takes an int length, even on 64-bit Windows
+#ifdef _WIN32
   size =
       (std::min)(size, static_cast<size_t>((std::numeric_limits<int>::max)()));
 #endif
@@ -13074,14 +13131,22 @@ make_host_and_port_string_always_port(const std::string &host, int port) {
   return prepare_host_string(host) + ":" + std::to_string(port);
 }
 
+// Where a client connects for `host`, as one string: the mapped address or
+// name, or `host` itself.
+inline std::string
+addr_map_target(const std::map<std::string, std::string> &addr_map,
+                const std::string &host) {
+  std::string connect_host;
+  std::string ip;
+  apply_addr_map(addr_map, host, connect_host, ip);
+  return ip.empty() ? connect_host : ip;
+}
+
 // Request target of a CONNECT for `host`, with `addr_map` applied.
 inline std::string
 make_connect_request_target(const std::map<std::string, std::string> &addr_map,
                             const std::string &host, int port) {
-  std::string connect_host;
-  std::string ip;
-  apply_addr_map(addr_map, host, connect_host, ip);
-  return make_host_and_port_string_always_port(ip.empty() ? connect_host : ip,
+  return make_host_and_port_string_always_port(addr_map_target(addr_map, host),
                                                port);
 }
 
@@ -15274,7 +15339,10 @@ Server::process_request(Stream &strm, const std::string &remote_addr,
   if ((req.method == "GET" || req.method == "HEAD") &&
       req.has_header("Range")) {
     const auto &range_header_value = req.get_header_value("Range");
-    if (!detail::parse_range_header(range_header_value, req.ranges)) {
+    // RFC 9110 14.2: a range unit other than bytes must be ignored
+    auto unit = range_header_value.substr(0, range_header_value.find('='));
+    if (detail::case_ignore::equal(unit, "bytes") &&
+        !detail::parse_range_header(range_header_value, req.ranges)) {
       connection_closed = true;
       res.status = StatusCode::RangeNotSatisfiable_416;
       output_error_log(Error::InvalidRangeHeader, &req);
@@ -15803,6 +15871,9 @@ inline bool ClientImpl::send_(Request &req, Response &res, Error &error) {
     // socket.
     socket_should_be_closed_when_request_is_done_ = false;
 
+    // A redirect or a retry sent inside a request keeps its stop()
+    if (socket_requests_in_flight_ == 0) { stop_requested_ = false; }
+
     if (!socket_reusable()) {
       if (!ensure_socket_connection(socket_, error)) { return false; }
 
@@ -15850,6 +15921,7 @@ inline bool ClientImpl::send_(Request &req, Response &res, Error &error) {
   });
 
   ret = process_socket(socket_, req.start_time_, [&](Stream &strm) {
+    strm.set_read_interrupt([this] { return stop_requested_.load(); });
     return handle_request(strm, req, res, close_connection, error);
   });
 
@@ -16462,8 +16534,13 @@ inline bool ClientImpl::redirect(Request &req, Response &res, Error &error) {
 
   auto path = std::move(next_path) + next_query;
 
+  // A Unix socket client sends "Host: localhost", so a Location naming
+  // localhost names this client too.
+  auto is_same_host = next_host == host_ ||
+                      (address_family_ == AF_UNIX && next_host == "localhost");
+
   // Same host redirect - use current client
-  if (next_scheme == scheme && next_host == host_ && next_port == port_) {
+  if (next_scheme == scheme && is_same_host && next_port == port_) {
     return detail::redirect(*this, req, res, path, location, error);
   }
 
@@ -16614,6 +16691,14 @@ inline void ClientImpl::setup_redirect_client(ClientType &client) {
   // Copy network and socket settings
   client.addr_map_ = addr_map_;
   client.tunnel_addr_map_ = tunnel_addr_map_;
+
+  // A Unix socket client reaches every host through its own socket, as curl's
+  // --unix-socket does, unless the caller mapped that host elsewhere. The
+  // Location's host is never taken as a socket path.
+  if (address_family_ == AF_UNIX) {
+    auto &target = client.addr_map_[client.host()];
+    if (target.empty()) { target = detail::addr_map_target(addr_map_, host_); }
+  }
   client.set_address_family(address_family_);
   client.set_tcp_nodelay(tcp_nodelay_);
   client.set_ipv6_v6only(ipv6_v6only_);
@@ -18068,6 +18153,9 @@ inline void ClientImpl::stop() {
   // are not thread-safe.
   if (socket_requests_in_flight_ > 0) {
     shutdown_socket(socket_);
+    // shutdown() does not wake a read waiting in WSAPoll on Windows, so the
+    // request's reads also give up once they see this flag.
+    stop_requested_ = true;
 
     // Aside from that, we set a flag for the socket to be closed when we're
     // done.
@@ -23030,6 +23118,9 @@ inline ssize_t read(session_t session, void *buf, size_t len, TlsError &err) {
   }
 
   auto wsession = static_cast<impl::WolfSSLSession *>(session);
+  constexpr auto max_len =
+      static_cast<size_t>((std::numeric_limits<int>::max)());
+  if (len > max_len) { len = max_len; }
   int ret = wolfSSL_read(wsession->ssl, buf, static_cast<int>(len));
 
   if (ret > 0) {

test/fuzzing/Makefile

@@ -13,14 +13,15 @@ ZLIB_SUPPORT = -DCPPHTTPLIB_ZLIB_SUPPORT -lz
 BROTLI_DIR = /usr/local/opt/brotli
 # BROTLI_SUPPORT = -DCPPHTTPLIB_BROTLI_SUPPORT -I$(BROTLI_DIR)/include -L$(BROTLI_DIR)/lib -lbrotlicommon -lbrotlienc -lbrotlidec
 
-FUZZERS = server_fuzzer url_parser_fuzzer header_parser_fuzzer client_fuzzer multipart_parser_fuzzer
+FUZZERS = server_fuzzer url_parser_fuzzer header_parser_fuzzer client_fuzzer multipart_parser_fuzzer websocket_fuzzer sse_parser_fuzzer server_mount_fuzzer
 
 # Runs all the tests and also fuzz tests against seed corpus.
 all : $(FUZZERS)
 	./server_fuzzer corpus/*
+	./server_mount_fuzzer corpus_mount/*
 
 # Fuzz target, so that you can choose which $(LIB_FUZZING_ENGINE) to use.
-server_fuzzer : server_fuzzer.cc ../../httplib.h
+server_fuzzer : server_fuzzer.cc fuzzed_stream.h ../../httplib.h
 # 	$(CXX) $(CXXFLAGS) -o $@  $<  -Wl,-Bstatic $(OPENSSL_SUPPORT)  -Wl,-Bdynamic -ldl  $(ZLIB_SUPPORT)  $(LIB_FUZZING_ENGINE) -pthread
 	$(CXX) $(CXXFLAGS) -o $@  $<  $(ZLIB_SUPPORT)  $(LIB_FUZZING_ENGINE) -pthread -lanl
 	zip -q -r server_fuzzer_seed_corpus.zip corpus
@@ -38,5 +39,15 @@ url_parser_fuzzer : url_parser_fuzzer.cc ../../httplib.h
 multipart_parser_fuzzer : multipart_parser_fuzzer.cc ../../httplib.h
 	$(CXX) $(CXXFLAGS) -o $@  $<  $(ZLIB_SUPPORT)  $(LIB_FUZZING_ENGINE) -pthread -lanl
 
+websocket_fuzzer : websocket_fuzzer.cc ../../httplib.h
+	$(CXX) $(CXXFLAGS) -o $@  $<  $(ZLIB_SUPPORT)  $(LIB_FUZZING_ENGINE) -pthread -lanl
+
+sse_parser_fuzzer : sse_parser_fuzzer.cc ../../httplib.h
+	$(CXX) $(CXXFLAGS) -o $@  $<  $(ZLIB_SUPPORT)  $(LIB_FUZZING_ENGINE) -pthread -lanl
+
+server_mount_fuzzer : server_mount_fuzzer.cc fuzzed_stream.h ../../httplib.h
+	$(CXX) $(CXXFLAGS) -o $@  $<  $(ZLIB_SUPPORT)  $(LIB_FUZZING_ENGINE) -pthread -lanl
+	zip -q -r server_mount_fuzzer_seed_corpus.zip corpus_mount
+
 clean:
 	rm -f server_fuzzer pem *.0 *.o *.1 *.srl *.zip

test/fuzzing/corpus_mount/mount-head

@@ -0,0 +1,3 @@
+HEAD /mnt/a.txt HTTP/1.1
+Host: x
+

test/fuzzing/corpus_mount/mount-ims

@@ -0,0 +1,4 @@
+GET /mnt/a.txt HTTP/1.1
+Host: x
+If-Modified-Since: Mon, 01 Jan 2024 00:00:00 GMT
+

test/fuzzing/corpus_mount/mount-index

@@ -0,0 +1,3 @@
+GET /mnt/index.html HTTP/1.1
+Host: x
+

test/fuzzing/corpus_mount/mount-inm

@@ -0,0 +1,4 @@
+GET /mnt/index.html HTTP/1.1
+Host: x
+If-None-Match: W/"bogusetag"
+

test/fuzzing/corpus_mount/mount-linkin

@@ -0,0 +1,3 @@
+GET /mnt/link-in.txt HTTP/1.1
+Host: x
+

test/fuzzing/corpus_mount/mount-linkout

@@ -0,0 +1,3 @@
+GET /mnt/link-out.txt HTTP/1.1
+Host: x
+

test/fuzzing/corpus_mount/mount-linksibling

@@ -0,0 +1,3 @@
+GET /mnt/link-sibling.txt HTTP/1.1
+Host: x
+

test/fuzzing/corpus_mount/mount-missing

@@ -0,0 +1,3 @@
+GET /mnt/missing.txt HTTP/1.1
+Host: x
+

test/fuzzing/corpus_mount/mount-range

@@ -0,0 +1,4 @@
+GET /mnt/a.txt HTTP/1.1
+Host: x
+Range: bytes=0-3
+

test/fuzzing/corpus_mount/mount-subdir

@@ -0,0 +1,3 @@
+GET /mnt/sub/ HTTP/1.1
+Host: x
+

test/fuzzing/corpus_mount/mount-traversal

@@ -0,0 +1,3 @@
+GET /mnt/../../../../etc/passwd HTTP/1.1
+Host: x
+

test/fuzzing/corpus_mount/mount-traversal-enc

@@ -0,0 +1,3 @@
+GET /mnt/%2e%2e/secret.txt HTTP/1.1
+Host: x
+

test/fuzzing/fuzzed_stream.h

@@ -0,0 +1,84 @@
+#pragma once
+
+#include <cstdint>
+
+#include <httplib.h>
+
+class FuzzedStream : public httplib::Stream {
+public:
+  FuzzedStream(const uint8_t *data, size_t size)
+      : data_(data), size_(size), read_pos_(0) {}
+
+  ssize_t read(char *ptr, size_t size) override {
+    if (size + read_pos_ > size_) { size = size_ - read_pos_; }
+    memcpy(ptr, data_ + read_pos_, size);
+    read_pos_ += size;
+    // Like SocketStream, pull in more than was asked for, which the line
+    // reader then takes through buffered_data(), so both of its paths run.
+    buffered_end_ =
+        (std::max)(buffered_end_, (std::min)(size_, read_pos_ + 4096));
+    return static_cast<ssize_t>(size);
+  }
+
+  const char *buffered_data(size_t &size) const override {
+    size = buffered_end_ > read_pos_ ? buffered_end_ - read_pos_ : 0;
+    return size ? reinterpret_cast<const char *>(data_ + read_pos_) : nullptr;
+  }
+
+  void consume_buffered(size_t size) override { read_pos_ += size; }
+
+  ssize_t write(const char *ptr, size_t size) override {
+    response_.append(ptr, size);
+    return static_cast<int>(size);
+  }
+
+  ssize_t write(const char *ptr) { return write(ptr, strlen(ptr)); }
+
+  ssize_t write(const std::string &s) { return write(s.data(), s.size()); }
+
+  bool is_readable() const override { return true; }
+
+  bool wait_readable() const override { return true; }
+
+  bool wait_writable() const override { return true; }
+
+  void get_remote_ip_and_port(std::string &ip, int &port) const override {
+    ip = "127.0.0.1";
+    port = 8080;
+  }
+
+  void get_local_ip_and_port(std::string &ip, int &port) const override {
+    ip = "127.0.0.1";
+    port = 8080;
+  }
+
+  socket_t socket() const override { return 0; }
+
+  time_t duration() const override { return 0; };
+
+  const std::string &response() const { return response_; }
+
+private:
+  const uint8_t *data_;
+  size_t size_;
+  size_t read_pos_;
+  size_t buffered_end_ = 0;
+  std::string response_;
+};
+
+class FuzzableServer : public httplib::Server {
+public:
+  // A server that is not listening counts as shutting down, and then writes
+  // no file. The socket is never used.
+  void MarkAsRunning() { svr_sock_ = 0; }
+
+  void ProcessFuzzedRequest(FuzzedStream &stream) {
+    bool connection_close = false;
+    process_request(stream,
+                    /*remote_addr=*/"",
+                    /*remote_port =*/0,
+                    /*local_addr=*/"",
+                    /*local_port =*/0,
+                    /*last_connection=*/false, connection_close, nullptr);
+  }
+};

test/fuzzing/server_fuzzer.cc

@@ -1,79 +1,4 @@
-#include <cstdint>
-
-#include <httplib.h>
-
-class FuzzedStream : public httplib::Stream {
-public:
-  FuzzedStream(const uint8_t *data, size_t size)
-      : data_(data), size_(size), read_pos_(0) {}
-
-  ssize_t read(char *ptr, size_t size) override {
-    if (size + read_pos_ > size_) { size = size_ - read_pos_; }
-    memcpy(ptr, data_ + read_pos_, size);
-    read_pos_ += size;
-    // Like SocketStream, pull in more than was asked for, which the line
-    // reader then takes through buffered_data(), so both of its paths run.
-    buffered_end_ =
-        (std::max)(buffered_end_, (std::min)(size_, read_pos_ + 4096));
-    return static_cast<ssize_t>(size);
-  }
-
-  const char *buffered_data(size_t &size) const override {
-    size = buffered_end_ > read_pos_ ? buffered_end_ - read_pos_ : 0;
-    return size ? reinterpret_cast<const char *>(data_ + read_pos_) : nullptr;
-  }
-
-  void consume_buffered(size_t size) override { read_pos_ += size; }
-
-  ssize_t write(const char *ptr, size_t size) override {
-    response_.append(ptr, size);
-    return static_cast<int>(size);
-  }
-
-  ssize_t write(const char *ptr) { return write(ptr, strlen(ptr)); }
-
-  ssize_t write(const std::string &s) { return write(s.data(), s.size()); }
-
-  bool is_readable() const override { return true; }
-
-  bool wait_readable() const override { return true; }
-
-  bool wait_writable() const override { return true; }
-
-  void get_remote_ip_and_port(std::string &ip, int &port) const override {
-    ip = "127.0.0.1";
-    port = 8080;
-  }
-
-  void get_local_ip_and_port(std::string &ip, int &port) const override {
-    ip = "127.0.0.1";
-    port = 8080;
-  }
-
-  socket_t socket() const override { return 0; }
-
-  time_t duration() const override { return 0; };
-
-private:
-  const uint8_t *data_;
-  size_t size_;
-  size_t read_pos_;
-  size_t buffered_end_ = 0;
-  std::string response_;
-};
-
-class FuzzableServer : public httplib::Server {
-public:
-  void ProcessFuzzedRequest(FuzzedStream &stream) {
-    bool connection_close = false;
-    process_request(stream,
-                    /*remote_addr=*/"",
-                    /*remote_port =*/0,
-                    /*local_addr=*/"",
-                    /*local_port =*/0,
-                    /*last_connection=*/false, connection_close, nullptr);
-  }
-};
+#include "fuzzed_stream.h"
 
 static FuzzableServer g_server;
 

test/fuzzing/server_mount_fuzzer.cc

@@ -0,0 +1,117 @@
+#include <cstdio>
+#include <cstdlib>
+#include <fstream>
+#include <random>
+#include <string>
+#include <vector>
+
+#include <sys/stat.h>
+#include <unistd.h>
+#include <utime.h>
+
+#include "fuzzed_stream.h"
+
+// Fixture layout, with <token> unknown to the fuzzer:
+//   root/mnt/{index.html,a.txt,data.bin,sub/index.html}  served at /mnt
+//   root/mnt/link-in.txt      -> a.txt (stays inside, may be served)
+//   root/mnt/link-out.txt     -> ../outside.txt (escapes, must be refused)
+//   root/mnt/link-sibling.txt -> ../mnt_secret/secret.txt (shares the "mnt"
+//                                prefix, must be refused)
+// The response must never contain <token>.
+
+namespace {
+
+FuzzableServer g_server;
+std::string g_root;
+std::string g_token;
+std::vector<std::string> g_paths; // In creation order
+
+void check(bool ok, const char *what) {
+  if (!ok) {
+    fprintf(stderr, "fixture setup failed: %s\n", what);
+    abort();
+  }
+}
+
+void make_dir(const std::string &path) {
+  check(mkdir(path.c_str(), 0755) == 0, path.c_str());
+  g_paths.push_back(path);
+}
+
+void make_file(const std::string &path, const std::string &content) {
+  {
+    std::ofstream out(path, std::ios::binary);
+    out << content;
+    check(out.good(), path.c_str());
+  }
+  // Fixed, so that conditional requests behave the same in every run
+  utimbuf times = {1700000000, 1700000000};
+  check(utime(path.c_str(), &times) == 0, path.c_str());
+  g_paths.push_back(path);
+}
+
+void make_link(const std::string &target, const std::string &path) {
+  check(symlink(target.c_str(), path.c_str()) == 0, path.c_str());
+  g_paths.push_back(path);
+}
+
+std::string serve(const uint8_t *data, size_t size) {
+  FuzzedStream stream{data, size};
+  g_server.ProcessFuzzedRequest(stream);
+  return stream.response();
+}
+
+void check_served(const char *path) {
+  auto req = std::string("GET ") + path + " HTTP/1.1\r\nHost: x\r\n\r\n";
+  auto res = serve(reinterpret_cast<const uint8_t *>(req.data()), req.size());
+  // Without this, a fuzzer that serves nothing would pass its check forever
+  check(res.find("abcdef") != std::string::npos, path);
+}
+
+void remove_fixture() {
+  for (auto it = g_paths.rbegin(); it != g_paths.rend(); ++it) {
+    if (unlink(it->c_str()) != 0) { rmdir(it->c_str()); }
+  }
+  rmdir(g_root.c_str());
+}
+
+} // namespace
+
+extern "C" int LLVMFuzzerInitialize(int * /*argc*/, char *** /*argv*/) {
+  std::random_device rd;
+  char token[33];
+  snprintf(token, sizeof(token), "%08x%08x%08x%08x", rd(), rd(), rd(), rd());
+  g_token = token;
+
+  auto tmpdir = getenv("TMPDIR");
+  auto tmpl = std::string(tmpdir && *tmpdir ? tmpdir : "/tmp") +
+              "/httplib-mount-XXXXXX";
+  check(mkdtemp(&tmpl[0]) != nullptr, tmpl.c_str());
+  g_root = tmpl;
+  atexit(remove_fixture);
+
+  auto mnt = g_root + "/mnt";
+  make_dir(mnt);
+  make_dir(mnt + "/sub");
+  make_dir(g_root + "/mnt_secret");
+  make_file(mnt + "/index.html", "<html>index</html>");
+  make_file(mnt + "/a.txt", "abcdef");
+  make_file(mnt + "/data.bin", std::string("\x01\x02\x03\x04\x05\x06", 6));
+  make_file(mnt + "/sub/index.html", "<html>sub</html>");
+  make_file(g_root + "/outside.txt", g_token);
+  make_file(g_root + "/mnt_secret/secret.txt", g_token);
+  make_link("a.txt", mnt + "/link-in.txt");
+  make_link("../outside.txt", mnt + "/link-out.txt");
+  make_link("../mnt_secret/secret.txt", mnt + "/link-sibling.txt");
+
+  g_server.MarkAsRunning();
+  check(g_server.set_mount_point("/mnt", mnt), "set_mount_point");
+  check_served("/mnt/a.txt");
+  check_served("/mnt/link-in.txt");
+  return 0;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  if (serve(data, size).find(g_token) != std::string::npos) { abort(); }
+  return 0;
+}

test/fuzzing/server_mount_fuzzer.dict

@@ -0,0 +1,24 @@
+"GET"
+"HEAD"
+"HTTP/1.1"
+
+"/mnt/"
+"/mnt/index.html"
+"/mnt/a.txt"
+"/mnt/data.bin"
+"/mnt/sub/"
+"/mnt/link-in.txt"
+"/mnt/link-out.txt"
+"/mnt/link-sibling.txt"
+".."
+"%2e%2e"
+"%2f"
+"//"
+
+"Range: bytes=0-"
+"Range: bytes=0-3,5-"
+"If-None-Match: "
+"W/"
+"If-Modified-Since: "
+"If-Range: "
+"Accept-Encoding: gzip"

test/fuzzing/sse_parser_fuzzer.cc

@@ -0,0 +1,49 @@
+#include <algorithm>
+#include <cstdint>
+#include <cstdlib>
+#include <string>
+
+#include <httplib.h>
+
+namespace {
+
+// Feeds the stream in chunks and records every handler call in order
+std::string parse_in_chunks(const std::string &stream, size_t chunk,
+                            size_t max_event_length) {
+  std::string trace;
+  httplib::detail::SSEParser parser(
+      [&](const httplib::sse::SSEMessage &msg) {
+        trace += "event[" + msg.event + "|" + msg.data + "|" + msg.id + "]";
+      },
+      [&](const std::string &id) { trace += "id[" + id + "]"; },
+      [&](int retry_ms) { trace += "retry[" + std::to_string(retry_ms) + "]"; },
+      max_event_length);
+
+  for (size_t off = 0; off < stream.size(); off += chunk) {
+    if (!parser.parse(stream.data() + off,
+                      std::min(chunk, stream.size() - off))) {
+      break;
+    }
+  }
+  return trace;
+}
+
+} // namespace
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  if (size < 2 || size > 65536) { return 0; }
+
+  // First byte selects the chunk size, the rest is the event stream
+  auto chunk = static_cast<size_t>(data[0]) + 1;
+  std::string stream(reinterpret_cast<const char *>(data + 1), size - 1);
+
+  // Without a length limit, chunking must not change what is reported
+  auto whole = parse_in_chunks(stream, stream.size(), 0);
+  auto chunked = parse_in_chunks(stream, chunk, 0);
+  if (whole != chunked) { std::abort(); }
+
+  // With a limit, only check that the parser stops cleanly
+  parse_in_chunks(stream, chunk, 64);
+
+  return 0;
+}

test/fuzzing/url_parser_fuzzer.cc

@@ -13,7 +13,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   size_t payload_size = size - 1;
   std::string input(payload, payload_size);
 
-  switch (selector % 6) {
+  switch (selector % 13) {
   case 0: {
     // parse_query_text
     httplib::Params params;
@@ -46,6 +46,48 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
     httplib::detail::is_valid_path(input);
     break;
   }
+  case 6: {
+    // parse_url
+    httplib::detail::UrlComponents uc;
+    httplib::detail::parse_url(input, uc);
+    break;
+  }
+  case 7: {
+    // remove_dot_segments
+    httplib::detail::remove_dot_segments(input);
+    break;
+  }
+  case 8: {
+    // resolve_relative_location, with the input as "<location>\n<base>"
+    auto nl = input.find('\n');
+    auto location = input.substr(0, nl);
+    auto base = nl == std::string::npos ? std::string("/index.html")
+                                        : input.substr(nl + 1);
+    httplib::detail::resolve_relative_location(location, base);
+    break;
+  }
+  case 9: {
+    // encode_path
+    httplib::detail::encode_path(input);
+    break;
+  }
+  case 10: {
+    // encode_uri_component, encode_uri
+    httplib::encode_uri_component(input);
+    httplib::encode_uri(input);
+    break;
+  }
+  case 11: {
+    // decode_uri_component, decode_uri
+    httplib::decode_uri_component(input);
+    httplib::decode_uri(input);
+    break;
+  }
+  case 12: {
+    // sanitize_filename
+    httplib::sanitize_filename(input);
+    break;
+  }
   }
 
   return 0;

test/fuzzing/websocket_fuzzer.cc

@@ -0,0 +1,54 @@
+#include <cstdint>
+#include <string>
+
+#include <httplib.h>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  if (size < 2) { return 0; }
+
+  auto selector = data[0];
+  std::string input(reinterpret_cast<const char *>(data + 1), size - 1);
+
+  switch (selector % 4) {
+  case 0: {
+    // read_websocket_frame. WebSocket::read passes the macro, close() passes
+    // 125, and 0 means no limit
+    static const size_t max_lens[] = {0, 125,
+                                      CPPHTTPLIB_WEBSOCKET_MAX_PAYLOAD_LENGTH};
+    auto expect_masked = (selector / 4) % 2 != 0;
+    auto max_len = max_lens[(selector / 8) % 3];
+    httplib::detail::BufferStream strm;
+    strm.write(input.data(), input.size());
+    auto opcode = httplib::ws::Opcode::Text;
+    std::string payload;
+    auto fin = false;
+    httplib::ws::impl::read_websocket_frame(strm, opcode, payload, fin,
+                                            expect_masked, max_len);
+    break;
+  }
+  case 1: {
+    // is_valid_utf8
+    httplib::ws::impl::is_valid_utf8(input);
+    break;
+  }
+  case 2: {
+    // is_valid_close_payload
+    httplib::ws::impl::is_valid_close_payload(input);
+    break;
+  }
+  case 3: {
+    // read_websocket_upgrade_response, with a fixed key since
+    // perform_websocket_handshake draws a random one
+    static const auto expected_accept =
+        httplib::detail::websocket_accept_key("dGhlIHNhbXBsZSBub25jZQ==");
+    httplib::detail::BufferStream strm;
+    strm.write(input.data(), input.size());
+    httplib::detail::WebSocketUpgradeResponse upgrade;
+    httplib::detail::read_websocket_upgrade_response(strm, expected_accept,
+                                                     "chat, stream", upgrade);
+    break;
+  }
+  }
+
+  return 0;
+}

test/fuzzing/websocket_fuzzer.options

@@ -0,0 +1,2 @@
+[libfuzzer]
+max_len = 70000

test/test.cc

@@ -291,6 +291,76 @@ TEST_F(UnixSocketTest, HostHeaderAutoSet) {
   EXPECT_EQ(received_host_header, "localhost");
 }
 
+TEST_F(UnixSocketTest, RedirectStaysOnSocket) {
+  // Another socket in the working directory, which a Location can name as
+  // its host
+  const auto other_path = "other-" + pathname_.substr(2);
+
+  httplib::Server svr;
+  svr.Get("/redirect", [&](const httplib::Request &, httplib::Response &res) {
+    // An absolute Location naming the Host this client sends
+    res.set_redirect("http://localhost" + pattern_);
+  });
+  svr.Get("/cross", [&](const httplib::Request &, httplib::Response &res) {
+    res.set_redirect("http://" + other_path + pattern_);
+  });
+  svr.Get("/mapped", [&](const httplib::Request &, httplib::Response &res) {
+    res.set_redirect("http://mapped.test" + pattern_);
+  });
+  svr.Get(pattern_, [&](const httplib::Request &req, httplib::Response &res) {
+    res.set_header("X-Auth", req.get_header_value("Authorization"));
+    res.set_content(content_, "text/plain");
+  });
+
+  httplib::Server other;
+  other.Get(pattern_, [&](const httplib::Request &, httplib::Response &res) {
+    res.set_content("other", "text/plain");
+  });
+
+  std::thread t{[&] {
+    ASSERT_TRUE(svr.set_address_family(AF_UNIX).listen(pathname_, 80));
+  }};
+  std::thread t2{[&] {
+    ASSERT_TRUE(other.set_address_family(AF_UNIX).listen(other_path, 80));
+  }};
+  auto se = detail::scope_exit([&] {
+    svr.stop();
+    other.stop();
+    t.join();
+    t2.join();
+    std::remove(other_path.c_str());
+  });
+
+  svr.wait_until_ready();
+  other.wait_until_ready();
+
+  httplib::Client cli{pathname_};
+  cli.set_address_family(AF_UNIX);
+  cli.set_follow_location(true);
+  cli.set_bearer_token_auth("token");
+
+  // Another host: the same socket, without the credentials
+  auto res = cli.Get("/cross");
+  ASSERT_TRUE(res) << "error: " << res.error();
+  EXPECT_EQ(StatusCode::OK_200, res->status);
+  EXPECT_EQ(content_, res->body);
+  EXPECT_EQ("", res->get_header_value("X-Auth"));
+
+  // localhost is this client's own host
+  res = cli.Get("/redirect");
+  ASSERT_TRUE(res) << "error: " << res.error();
+  EXPECT_EQ(StatusCode::OK_200, res->status);
+  EXPECT_EQ(content_, res->body);
+  EXPECT_EQ("Bearer token", res->get_header_value("X-Auth"));
+
+  // A host the caller mapped to a socket goes there
+  cli.set_direct_hostname_addr_map({{"mapped.test", other_path}});
+  res = cli.Get("/mapped");
+  ASSERT_TRUE(res) << "error: " << res.error();
+  EXPECT_EQ(StatusCode::OK_200, res->status);
+  EXPECT_EQ("other", res->body);
+}
+
 #ifndef _WIN32
 TEST(SocketStream, wait_writable_UNIX) {
   int fds[2];
@@ -2322,6 +2392,13 @@ TEST(HeadersOrderTest, ErasingByNameKeepsTheRemainingOrder) {
   EXPECT_EQ("B=2 C=4 ", entries_to_string(headers));
 }
 
+TEST(HeadersOrderTest, ErasingAnAliasedNameKeepsTheRemainingOrder) {
+  Headers headers = {{"A", "1"}, {"B", "2"}, {"a", "3"}, {"B", "4"}};
+
+  EXPECT_EQ(2U, headers.erase(headers.begin()->first));
+  EXPECT_EQ("B=2 B=4 ", entries_to_string(headers));
+}
+
 TEST(HeadersOrderTest, EmplaceFrontPrepends) {
   Headers headers = {{"Accept", "*/*"}, {"User-Agent", "test"}};
   headers.emplace_front("Host", "example.com");
@@ -2818,6 +2895,35 @@ TEST(RangeTest, IgnoredForPost) {
   }
 }
 
+TEST(RangeTest, IgnoredForUnknownUnit) {
+  Server svr;
+  svr.Get("/", [](const Request &, Response &res) {
+    res.set_content("abcdefg", "text/plain");
+  });
+
+  auto port = svr.bind_to_any_port(HOST);
+  ASSERT_GT(port, 0);
+  thread t = thread([&] { svr.listen_after_bind(); });
+  auto se = detail::scope_exit([&] {
+    svr.stop();
+    t.join();
+    ASSERT_FALSE(svr.is_running());
+  });
+  svr.wait_until_ready();
+
+  Client cli(HOST, port);
+  for (auto range : {"items=1-2", "none=x"}) {
+    auto res = cli.Get("/", Headers{{"Range", range}});
+    ASSERT_TRUE(res) << range << ": " << to_string(res.error());
+    EXPECT_EQ(StatusCode::OK_200, res->status) << range;
+    EXPECT_EQ("abcdefg", res->body) << range;
+  }
+
+  auto res = cli.Get("/", Headers{{"Range", "bytes=x"}});
+  ASSERT_TRUE(res) << to_string(res.error());
+  EXPECT_EQ(StatusCode::RangeNotSatisfiable_416, res->status);
+}
+
 TEST(GetAddrInfoDanglingRefTest, LongTimeout) {
   auto host = "unresolvableaddress.local";
   auto path = std::string{"/"};
@@ -3445,6 +3551,55 @@ TEST(CancelTest, WithCancelLargePayloadDelete) {
   EXPECT_EQ(Error::Canceled, res.error());
 }
 
+// One stop() from another thread ends a request that waits for the response
+TEST(ClientStopTest, StopEndsWaitForResponse) {
+  Server svr;
+  std::atomic<bool> received{false};
+  std::atomic<bool> done{false};
+
+  svr.Get("/wait", [&](const Request & /*req*/, Response &res) {
+    received.store(true);
+    while (!done.load()) {
+      std::this_thread::sleep_for(std::chrono::milliseconds(10));
+    }
+    res.set_content("Hello World!", "text/plain");
+  });
+  auto port = svr.bind_to_any_port(HOST);
+  auto thread = std::thread([&]() { svr.listen_after_bind(); });
+
+  Client cli(HOST, port);
+  cli.set_read_timeout(std::chrono::seconds(30));
+  std::future<Result> request;
+
+  auto se = detail::scope_exit([&] {
+    done.store(true);
+    svr.stop();
+    thread.join();
+    ASSERT_FALSE(svr.is_running());
+  });
+
+  svr.wait_until_ready();
+
+  request = std::async(std::launch::async, [&]() { return cli.Get("/wait"); });
+
+  for (int i = 0; i < 500 && !received.load(); ++i) {
+    std::this_thread::sleep_for(std::chrono::milliseconds(10));
+  }
+  ASSERT_TRUE(received.load());
+  // Let the client block in the wait for the response
+  std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+  auto start = std::chrono::steady_clock::now();
+  cli.stop();
+  ASSERT_EQ(std::future_status::ready,
+            request.wait_for(std::chrono::seconds(5)));
+  EXPECT_LT(std::chrono::steady_clock::now() - start, std::chrono::seconds(2));
+
+  auto res = request.get();
+  ASSERT_TRUE(!res);
+  EXPECT_EQ(Error::Read, res.error());
+}
+
 static std::string remove_whitespace(const std::string &input) {
   std::string output;
   output.reserve(input.size());
@@ -4248,6 +4403,62 @@ TEST(RedirectToSamePort, ForwardCookie) {
   EXPECT_EQ("session_id=SECRET", captured_cookie);
 }
 
+TEST(RedirectTest, DoNotCarryRequestParamsToLocation) {
+  // The Location alone names the next target, on any origin.
+  Server target_svr;
+  std::string cross_target;
+  target_svr.Get("/landing", [&](const Request &req, Response &res) {
+    cross_target = req.target;
+    res.set_content("OK", "text/plain");
+  });
+
+  auto target_port = target_svr.bind_to_any_port(HOST);
+  auto target_thread = std::thread([&]() { target_svr.listen_after_bind(); });
+
+  Server origin_svr;
+  std::string same_target;
+  origin_svr.Get("/cross", [&](const Request &, Response &res) {
+    res.set_redirect(
+        "http://localhost:" + std::to_string(target_port) + "/landing", 302);
+  });
+  origin_svr.Get("/same", [&](const Request &, Response &res) {
+    res.set_redirect("/landing", 302);
+  });
+  origin_svr.Get("/landing", [&](const Request &req, Response &res) {
+    same_target = req.target;
+    res.set_content("OK", "text/plain");
+  });
+
+  auto origin_port = origin_svr.bind_to_any_port(HOST);
+  auto origin_thread = std::thread([&]() { origin_svr.listen_after_bind(); });
+  auto se = detail::scope_exit([&] {
+    origin_svr.stop();
+    origin_thread.join();
+    target_svr.stop();
+    target_thread.join();
+  });
+
+  target_svr.wait_until_ready();
+  origin_svr.wait_until_ready();
+
+  Client cli("localhost", origin_port);
+  cli.set_follow_location(true);
+
+  Request req;
+  req.method = "GET";
+  req.params = {{"api_key", "SECRET"}};
+
+  req.path = "/cross";
+  auto res = cli.send(req);
+  ASSERT_TRUE(res) << "Error: " << to_string(res.error());
+  EXPECT_EQ("/landing", cross_target);
+
+  req.path = "/same";
+  res = cli.send(req);
+  ASSERT_TRUE(res) << "Error: " << to_string(res.error());
+  EXPECT_EQ("/landing", same_target);
+}
+
 TEST(RedirectToDifferentPort, ForwardDefaultHeadersButNotCredentials) {
   std::string authorization;
   std::string trace_id;
@@ -20676,6 +20887,13 @@ TEST(RedirectTest, ResolveRelativeLocation) {
               detail::resolve_relative_location(c.first, "/b/c/d;p?q"))
         << c.first;
   }
+
+  // A result starting with "//" is still a path, not a network-path reference
+  EXPECT_EQ("/.//g",
+            detail::resolve_relative_location("../../..//g", "/b/c/d;p?q"));
+  EXPECT_EQ("/.//g/x", detail::resolve_relative_location("x", "//g/h"));
+  EXPECT_EQ("/.//g/h?y", detail::resolve_relative_location("?y", "//g/h"));
+  EXPECT_EQ("/.//g/h#s", detail::resolve_relative_location("#s", "//g/h"));
 }
 
 TEST(RedirectTest, RemoveDotSegments) {
@@ -20763,6 +20981,54 @@ TEST(RedirectTest, RelativeLocationWithoutLeadingSlash) {
   }
 }
 
+// "..//host:port/x" resolves to the path "//host:port/x" on the same host
+// (RFC 3986 5.2), as curl and the URL Standard have it, not to another host.
+TEST(RedirectTest, RelativeLocationStaysOnHost) {
+  Server other;
+  std::atomic<int> other_hits{0};
+  other.Get(".*", [&](const Request & /*req*/, Response &res) {
+    other_hits++;
+    res.set_content("other", "text/plain");
+  });
+  auto other_port = other.bind_to_any_port("127.0.0.1");
+  auto other_thread = std::thread([&]() { other.listen_after_bind(); });
+
+  Server svr;
+  svr.Get("/dir/page", [](const Request &req, Response &res) {
+    res.set_redirect(req.get_param_value("to"));
+  });
+  svr.Get(".*", [](const Request &req, Response &res) {
+    res.set_content(req.path, "text/plain");
+  });
+  auto port = svr.bind_to_any_port(HOST);
+  auto thread = std::thread([&]() { svr.listen_after_bind(); });
+
+  auto se = detail::scope_exit([&] {
+    svr.stop();
+    thread.join();
+    other.stop();
+    other_thread.join();
+    ASSERT_FALSE(svr.is_running());
+    ASSERT_FALSE(other.is_running());
+  });
+
+  svr.wait_until_ready();
+  other.wait_until_ready();
+
+  auto authority = "127.0.0.1:" + std::to_string(other_port);
+  for (const auto &to :
+       {"..//" + authority + "/x", "../..//" + authority + "/x"}) {
+    Client cli(HOST, port);
+    cli.set_follow_location(true);
+
+    auto res = cli.Get("/dir/page?to=" + encode_query_component(to));
+    ASSERT_TRUE(res) << to << ": " << to_string(res.error());
+    EXPECT_EQ(StatusCode::OK_200, res->status) << to;
+    EXPECT_EQ("//" + authority + "/x", res->body) << to;
+  }
+  EXPECT_EQ(0, other_hits.load());
+}
+
 #ifdef CPPHTTPLIB_SSL_ENABLED
 TEST(RedirectTest, Issue2185_Online) {
   SSLClient client("github.com");
@@ -24952,6 +25218,49 @@ TEST(SSLTest, ResponseBodyTerminatedByConnectionClose) {
   EXPECT_EQ(StatusCode::OK_200, res->status);
   EXPECT_EQ(expected_body, res->body);
 }
+
+// Without Content-Length, the full buffer size reaches tls::read().
+TEST(SSLTest, ReadIntoBufferOverIntMax) {
+  if (sizeof(size_t) <= sizeof(int)) {
+    GTEST_SKIP() << "size_t cannot exceed INT_MAX here";
+  }
+
+  SSLServer svr(SERVER_CERT_FILE, SERVER_PRIVATE_KEY_FILE);
+  ASSERT_TRUE(svr.is_valid());
+
+  svr.Get("/no-content-length", [&](const Request & /*req*/, Response &res) {
+    res.set_content_provider("text/plain",
+                             [&](size_t offset, DataSink &sink) -> bool {
+                               if (offset == 0) { sink.write("Hello", 5); }
+                               sink.done();
+                               return true;
+                             });
+  });
+
+  auto port = svr.bind_to_any_port(HOST);
+  auto listen_thread = std::thread([&svr] { svr.listen_after_bind(); });
+  auto se = detail::scope_exit([&] {
+    svr.stop();
+    listen_thread.join();
+  });
+  svr.wait_until_ready();
+
+  SSLClient cli(HOST, port);
+  cli.enable_server_certificate_verification(false);
+
+  auto handle = cli.open_stream("GET", "/no-content-length");
+  ASSERT_TRUE(handle.is_valid()) << to_string(handle.error);
+
+  const auto len = static_cast<size_t>((std::numeric_limits<int>::max)()) + 1;
+  std::unique_ptr<char[]> buf(new char[len]);
+  std::string body;
+  ssize_t n;
+  while ((n = handle.read(buf.get(), len)) > 0) {
+    body.append(buf.get(), static_cast<size_t>(n));
+  }
+  EXPECT_EQ(0, n);
+  EXPECT_EQ("Hello", body);
+}
 #endif // CPPHTTPLIB_SSL_ENABLED
 
 //==============================================================================
@@ -26235,264 +26544,264 @@ protected:
 };
 
 //==============================================================================
-// SSE Parsing Tests
+// SSE Parser Tests
 //==============================================================================
 
-class SSEParsingTest : public SSEIntegrationTest {
-protected:
-  // Feeds a raw event stream to SSEClient and returns the dispatched messages.
-  // A trailing sentinel event tells when the whole stream has been parsed.
-  std::vector<sse::SSEMessage> parse(const std::string &stream) {
-    auto body = stream + "event: end\ndata: end\n\n";
-    server_->Get("/parse", [body](const Request &, Response &res) {
-      res.set_content(body, "text/event-stream");
-    });
-    return collect("/parse");
-  }
-
-  // Runs SSEClient against path until an "end" event arrives and returns the
-  // messages dispatched before it
-  std::vector<sse::SSEMessage> collect(const std::string &path) {
-    Client client(HOST, get_port());
-    sse::SSEClient sse(client, path);
-    std::mutex mutex;
-    std::condition_variable cv;
-    std::vector<sse::SSEMessage> messages;
-    auto done = false;
-
-    sse.on_message([&](const sse::SSEMessage &msg) {
-      std::lock_guard<std::mutex> lock(mutex);
-      // Ignore a replay from a reconnect that races with stop()
-      if (!done) { messages.push_back(msg); }
-    });
-    sse.on_event("end", [&](const sse::SSEMessage &) {
-      std::lock_guard<std::mutex> lock(mutex);
-      done = true;
-      cv.notify_all();
-    });
-    sse.set_reconnect_interval(100);
-    sse.start_async();
-
-    {
-      std::unique_lock<std::mutex> lock(mutex);
-      cv.wait_for(lock, std::chrono::seconds(5), [&] { return done; });
-    }
-    sse.stop();
-
-    EXPECT_TRUE(done);
-    return messages;
-  }
+struct SSEParseResult {
+  std::vector<sse::SSEMessage> events;
+  std::vector<std::string> ids;
+  std::vector<int> retries;
+  bool ok = true;
+  std::string trace; // Every handler call in order
 };
 
-TEST_F(SSEParsingTest, SingleLineData) {
-  auto msgs = parse("data: hello\n\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].data, "hello");
-  EXPECT_EQ(msgs[0].event, "message");
+static SSEParseResult
+sse_parse(const std::vector<std::string> &chunks,
+          size_t max_event_length = CPPHTTPLIB_SSE_MAX_EVENT_LENGTH) {
+  SSEParseResult r;
+  detail::SSEParser parser(
+      [&](const sse::SSEMessage &msg) {
+        r.events.push_back(msg);
+        r.trace += "event[" + msg.event + "|" + msg.data + "|" + msg.id + "]";
+      },
+      [&](const std::string &id) {
+        r.ids.push_back(id);
+        r.trace += "id[" + id + "]";
+      },
+      [&](int retry_ms) {
+        r.retries.push_back(retry_ms);
+        r.trace += "retry[" + std::to_string(retry_ms) + "]";
+      },
+      max_event_length);
+  for (const auto &chunk : chunks) {
+    if (!parser.parse(chunk.data(), chunk.size())) {
+      r.ok = false;
+      break;
+    }
+  }
+  return r;
 }
 
-TEST_F(SSEParsingTest, MultiLineData) {
-  auto msgs = parse("data: line1\ndata: line2\ndata: line3\n\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].data, "line1\nline2\nline3");
+static SSEParseResult sse_parse(const std::string &stream) {
+  return sse_parse(std::vector<std::string>{stream});
 }
 
-TEST_F(SSEParsingTest, CustomEventType) {
-  auto msgs = parse("event: update\ndata: payload\n\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].event, "update");
-  EXPECT_EQ(msgs[0].data, "payload");
+TEST(SSEParserTest, SingleLineData) {
+  auto r = sse_parse("data: hello\n\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].data, "hello");
+  EXPECT_EQ(r.events[0].event, "message");
 }
 
-TEST_F(SSEParsingTest, EventIdHandling) {
-  auto msgs = parse("id: 12345\ndata: test\n\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].id, "12345");
+TEST(SSEParserTest, MultiLineData) {
+  auto r = sse_parse("data: line1\ndata: line2\ndata: line3\n\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].data, "line1\nline2\nline3");
 }
 
-TEST_F(SSEParsingTest, EmptyEventId) {
-  auto msgs = parse("id:\ndata: test\n\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].id, "");
+TEST(SSEParserTest, CustomEventType) {
+  auto r = sse_parse("event: update\ndata: payload\n\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].event, "update");
+  EXPECT_EQ(r.events[0].data, "payload");
 }
 
-TEST_F(SSEParsingTest, CommentsIgnored) {
-  auto msgs = parse(": this is a comment\ndata: hello\n\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].data, "hello");
-  EXPECT_EQ(msgs[0].event, "message");
+TEST(SSEParserTest, EventIdHandling) {
+  auto r = sse_parse("id: 12345\ndata: test\n\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].id, "12345");
+  EXPECT_EQ(r.ids, std::vector<std::string>{"12345"});
 }
 
-TEST_F(SSEParsingTest, ColonInValue) {
-  auto msgs = parse("data: hello:world:test\n\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].data, "hello:world:test");
+TEST(SSEParserTest, EmptyEventId) {
+  auto r = sse_parse("id:\ndata: test\n\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].id, "");
+  EXPECT_EQ(r.ids, std::vector<std::string>{""});
 }
 
-TEST_F(SSEParsingTest, FieldNameOnly) {
+TEST(SSEParserTest, CommentsIgnored) {
+  auto r = sse_parse(": this is a comment\ndata: hello\n\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].data, "hello");
+  EXPECT_EQ(r.events[0].event, "message");
+}
+
+TEST(SSEParserTest, ColonInValue) {
+  auto r = sse_parse("data: hello:world:test\n\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].data, "hello:world:test");
+}
+
+TEST(SSEParserTest, FieldNameOnly) {
   // A line without a colon is a field name with an empty value
-  auto msgs = parse("data\n\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].data, "");
+  auto r = sse_parse("data\n\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].data, "");
 }
 
-TEST_F(SSEParsingTest, TrailingCarriageReturn) {
-  auto msgs = parse("event: update\r\ndata: hello\r\n\r\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].event, "update");
-  EXPECT_EQ(msgs[0].data, "hello");
+TEST(SSEParserTest, TrailingCarriageReturn) {
+  auto r = sse_parse("event: update\r\ndata: hello\r\n\r\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].event, "update");
+  EXPECT_EQ(r.events[0].data, "hello");
 }
 
-TEST_F(SSEParsingTest, FieldNameOnlyWithCarriageReturn) {
-  auto msgs = parse("data\r\n\r\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].data, "");
+TEST(SSEParserTest, FieldNameOnlyWithCarriageReturn) {
+  auto r = sse_parse("data\r\n\r\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].data, "");
 }
 
-TEST_F(SSEParsingTest, CarriageReturnLineEnding) {
-  auto msgs = parse("event: update\rdata: hello\r\r");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].event, "update");
-  EXPECT_EQ(msgs[0].data, "hello");
+TEST(SSEParserTest, CarriageReturnLineEnding) {
+  auto r = sse_parse("event: update\rdata: hello\r\r");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].event, "update");
+  EXPECT_EQ(r.events[0].data, "hello");
 }
 
-TEST_F(SSEParsingTest, LineEndingSplitAcrossChunks) {
+TEST(SSEParserTest, LineEndingSplitAcrossChunks) {
   // Chunk boundaries fall inside every \r\n and right before the first one
-  std::vector<std::string> chunks = {"event: update", "\r", "\ndata: hello\r",
-                                     "\n\r", "\nevent: end\ndata: end\n\n"};
-  server_->Get("/split", [chunks](const Request &, Response &res) {
-    auto i = std::make_shared<size_t>(0);
-    res.set_chunked_content_provider(
-        "text/event-stream", [chunks, i](size_t /*offset*/, DataSink &sink) {
-          if (*i == chunks.size()) {
-            sink.done();
-          } else {
-            sink.write(chunks[*i].data(), chunks[*i].size());
-            (*i)++;
-          }
-          return true;
-        });
-  });
-
-  auto msgs = collect("/split");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].event, "update");
-  EXPECT_EQ(msgs[0].data, "hello");
+  auto r = sse_parse(std::vector<std::string>{"event: update", "\r",
+                                              "\ndata: hello\r", "\n\r", "\n"});
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].event, "update");
+  EXPECT_EQ(r.events[0].data, "hello");
 }
 
-TEST_F(SSEParsingTest, LeadingByteOrderMarkIgnored) {
+TEST(SSEParserTest, LeadingByteOrderMarkIgnored) {
   // Only a BOM at the start of the stream is ignored
-  auto msgs = parse("\xEF\xBB\xBF"
-                    "data: first\n\n"
-                    "\xEF\xBB\xBF"
-                    "data: second\n\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].data, "first");
+  auto r = sse_parse("\xEF\xBB\xBF"
+                     "data: first\n\n"
+                     "\xEF\xBB\xBF"
+                     "data: second\n\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].data, "first");
 }
 
-TEST_F(SSEParsingTest, UnknownFieldsIgnored) {
-  auto msgs = parse("unknown: value\ndata: hello\n\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].data, "hello");
-  EXPECT_EQ(msgs[0].event, "message");
+TEST(SSEParserTest, UnknownFieldsIgnored) {
+  auto r = sse_parse("unknown: value\ndata: hello\n\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].data, "hello");
+  EXPECT_EQ(r.events[0].event, "message");
 }
 
-TEST_F(SSEParsingTest, SpaceAfterColonOptional) {
-  auto msgs = parse("data: hello\n\ndata:hello\n\n");
-  ASSERT_EQ(msgs.size(), 2u);
-  EXPECT_EQ(msgs[0].data, "hello");
-  EXPECT_EQ(msgs[1].data, "hello");
+TEST(SSEParserTest, SpaceAfterColonOptional) {
+  auto r = sse_parse("data: hello\n\ndata:hello\n\n");
+  ASSERT_EQ(r.events.size(), 2u);
+  EXPECT_EQ(r.events[0].data, "hello");
+  EXPECT_EQ(r.events[1].data, "hello");
 }
 
-TEST_F(SSEParsingTest, EventWithoutDataResetsEventType) {
+TEST(SSEParserTest, EventWithoutDataResetsEventType) {
   // An event without data is not dispatched, and its type must not leak
   // into the next event
-  auto msgs = parse("event: update\n\ndata: hello\n\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].event, "message");
-  EXPECT_EQ(msgs[0].data, "hello");
+  auto r = sse_parse("event: update\n\ndata: hello\n\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].event, "message");
+  EXPECT_EQ(r.events[0].data, "hello");
 }
 
-TEST_F(SSEParsingTest, EmptyEventTypeIsMessage) {
+TEST(SSEParserTest, EmptyEventTypeIsMessage) {
   // Also when the empty field replaces an earlier type
-  auto msgs = parse("event:\ndata: a\n\nevent: update\nevent:\ndata: b\n\n");
-  ASSERT_EQ(msgs.size(), 2u);
-  EXPECT_EQ(msgs[0].event, "message");
-  EXPECT_EQ(msgs[1].event, "message");
+  auto r = sse_parse("event:\ndata: a\n\nevent: update\nevent:\ndata: b\n\n");
+  ASSERT_EQ(r.events.size(), 2u);
+  EXPECT_EQ(r.events[0].event, "message");
+  EXPECT_EQ(r.events[1].event, "message");
 }
 
-TEST_F(SSEParsingTest, EventWithoutDataUpdatesLastEventId) {
-  // The first connection sends only an id; the second echoes back the
-  // Last-Event-ID it was reconnected with
-  std::atomic<int> connection_count{0};
-  server_->Get("/id-only", [&](const Request &req, Response &res) {
-    if (connection_count++ == 0) {
-      res.set_content("id: 42\n\n", "text/event-stream");
-    } else {
-      res.set_content("data: " + req.get_header_value("Last-Event-ID") +
-                          "\n\nevent: end\ndata: end\n\n",
-                      "text/event-stream");
+TEST(SSEParserTest, EventWithoutDataReportsId) {
+  auto r = sse_parse("id: 42\n\n");
+  EXPECT_TRUE(r.events.empty());
+  EXPECT_EQ(r.ids, std::vector<std::string>{"42"});
+}
+
+TEST(SSEParserTest, EmptyEventIdClearsId) {
+  auto r = sse_parse("id: 1\ndata: first\n\nid:\ndata: second\n\n");
+  ASSERT_EQ(r.events.size(), 2u);
+  EXPECT_EQ(r.events[0].id, "1");
+  EXPECT_EQ(r.events[1].id, "");
+  EXPECT_EQ(r.ids, (std::vector<std::string>{"1", ""}));
+}
+
+TEST(SSEParserTest, UnsendableEventIdIgnored) {
+  // Ids that cannot be carried in a Last-Event-ID header
+  auto r = sse_parse(std::string("id: 42\n\nid: a") + '\0' +
+                     "b\n\nid: \x01\n\nid:  7\n\nid: 7 \n\n");
+  EXPECT_EQ(r.ids, std::vector<std::string>{"42"});
+}
+
+TEST(SSEParserTest, RetryDigitsOnly) {
+  auto r = sse_parse("retry: 1000\n");
+  EXPECT_EQ(r.retries, std::vector<int>{1000});
+
+  // A value that is not all ASCII digits, or does not fit, is ignored
+  r = sse_parse("retry: -1\nretry: 1.5\nretry:\nretry: 99999999999\n");
+  EXPECT_TRUE(r.retries.empty());
+}
+
+TEST(SSEParserTest, CompleteEventParsing) {
+  auto r = sse_parse("event: notification\nid: evt-42\n"
+                     "data: {\"type\":\"alert\"}\nretry: 1000\n\n");
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].event, "notification");
+  EXPECT_EQ(r.events[0].id, "evt-42");
+  EXPECT_EQ(r.events[0].data, "{\"type\":\"alert\"}");
+  EXPECT_EQ(r.retries, std::vector<int>{1000});
+}
+
+TEST(SSEParserTest, IncompleteEventNotReported) {
+  // An event still waiting for its blank line when the stream ends is
+  // discarded per the SSE spec
+  auto r = sse_parse("id: 1\ndata: x\n");
+  EXPECT_TRUE(r.events.empty());
+  EXPECT_TRUE(r.ids.empty());
+}
+
+TEST(SSEParserTest, SameResultAtEveryChunkBoundary) {
+  const std::vector<std::string> streams = {
+      "\xEF\xBB\xBF"
+      "data: bom\r\n\r\n",
+      "event: a\r\ndata: 1\r\nid: x\r\n\r\ndata: 2\rretry: 7\r\r",
+      ": comment\ndata\nid:\n\nid: y\n\ndata: tail\r\n\r\n",
+  };
+  for (const auto &stream : streams) {
+    auto expected = sse_parse(stream).trace;
+    ASSERT_FALSE(expected.empty());
+
+    for (size_t i = 0; i <= stream.size(); i++) {
+      auto r = sse_parse(
+          std::vector<std::string>{stream.substr(0, i), stream.substr(i)});
+      EXPECT_EQ(r.trace, expected) << "split at " << i;
     }
-  });
 
-  auto msgs = collect("/id-only");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].data, "42");
-}
-
-TEST_F(SSEParsingTest, EmptyEventIdClearsLastEventId) {
-  // The first connection sets an id and then clears it with an empty one; the
-  // second reports whether it was reconnected with a Last-Event-ID
-  std::atomic<int> connection_count{0};
-  server_->Get("/id-clear", [&](const Request &req, Response &res) {
-    if (connection_count++ == 0) {
-      res.set_content("id: 1\ndata: first\n\nid:\ndata: second\n\n",
-                      "text/event-stream");
-    } else {
-      res.set_content(
-          std::string("data: ") +
-              (req.has_header("Last-Event-ID") ? "sent" : "not sent") +
-              "\n\nevent: end\ndata: end\n\n",
-          "text/event-stream");
+    std::vector<std::string> bytes;
+    for (auto c : stream) {
+      bytes.emplace_back(1, c);
     }
-  });
-
-  auto msgs = collect("/id-clear");
-  ASSERT_EQ(msgs.size(), 3u);
-  EXPECT_EQ(msgs[0].id, "1");
-  EXPECT_EQ(msgs[1].id, "");
-  EXPECT_EQ(msgs[2].data, "not sent");
+    EXPECT_EQ(sse_parse(bytes).trace, expected) << "byte by byte";
+  }
 }
 
-TEST_F(SSEParsingTest, UnsendableEventIdKeepsLastEventId) {
-  // The first connection sets an id and then sends ids that cannot be carried
-  // in a header; the second echoes back the Last-Event-ID it was reconnected
-  // with
-  std::atomic<int> connection_count{0};
-  server_->Get("/id-unsendable", [&](const Request &req, Response &res) {
-    if (connection_count++ == 0) {
-      res.set_content(std::string("id: 42\n\nid: a") + '\0' +
-                          "b\n\nid: \x01\n\nid:  7\n\nid: 7 \n\n",
-                      "text/event-stream");
-    } else {
-      res.set_content("data: " + req.get_header_value("Last-Event-ID") +
-                          "\n\nevent: end\ndata: end\n\n",
-                      "text/event-stream");
-    }
-  });
+TEST(SSEParserTest, MaxEventLength) {
+  // A line still waiting for its end
+  EXPECT_TRUE(sse_parse(std::vector<std::string>{"data: 12"}, 8).ok);
+  EXPECT_FALSE(sse_parse(std::vector<std::string>{"data: 123"}, 8).ok);
 
-  auto msgs = collect("/id-unsendable");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].data, "42");
-}
+  // Data accumulated over the lines of one event
+  EXPECT_TRUE(
+      sse_parse(std::vector<std::string>{"data: 1234\ndata: 567\n"}, 8).ok);
+  EXPECT_FALSE(
+      sse_parse(std::vector<std::string>{"data: 1234\ndata: 5678\n"}, 8).ok);
 
-TEST_F(SSEParsingTest, CompleteEventParsing) {
-  auto msgs = parse("event: notification\nid: evt-42\n"
-                    "data: {\"type\":\"alert\"}\nretry: 1000\n\n");
-  ASSERT_EQ(msgs.size(), 1u);
-  EXPECT_EQ(msgs[0].event, "notification");
-  EXPECT_EQ(msgs[0].id, "evt-42");
-  EXPECT_EQ(msgs[0].data, "{\"type\":\"alert\"}");
+  // 0 means no limit
+  EXPECT_TRUE(sse_parse(std::vector<std::string>{"data: 123"}, 0).ok);
+
+  // Events completed in the same chunk are still reported
+  auto r = sse_parse(std::vector<std::string>{"data: a\n\ndata: 123456789"}, 8);
+  EXPECT_FALSE(r.ok);
+  ASSERT_EQ(r.events.size(), 1u);
+  EXPECT_EQ(r.events[0].data, "a");
 }
 
 TEST(SSEMessageTest, Clear) {
@@ -27117,35 +27426,6 @@ TEST_F(SSEIntegrationTest, StreamEndingAtConnectionCloseIsNotAnError) {
   EXPECT_EQ(0, error_count.load());
 }
 
-// Test: A retry field that is not all ASCII digits is ignored
-TEST_F(SSEIntegrationTest, NonDigitRetryFieldIgnored) {
-  std::atomic<int> connection_count{0};
-
-  server_->Get("/bad-retry",
-               [&connection_count](const Request &, Response &res) {
-                 connection_count.fetch_add(1);
-                 res.set_chunked_content_provider(
-                     "text/event-stream", [](size_t offset, DataSink &sink) {
-                       if (offset == 0) {
-                         std::string event = "retry: -1\ndata: hello\n\n";
-                         sink.write(event.data(), event.size());
-                       }
-                       return false;
-                     });
-               });
-
-  Client client("localhost", get_port());
-  sse::SSEClient sse(client, "/bad-retry");
-
-  sse.set_reconnect_interval(10000);
-  sse.start_async();
-
-  std::this_thread::sleep_for(std::chrono::milliseconds(500));
-  sse.stop();
-
-  EXPECT_EQ(connection_count.load(), 1);
-}
-
 // Test: A retry field of all ASCII digits sets the reconnection time
 TEST_F(SSEIntegrationTest, DigitRetryFieldApplied) {
   std::mutex mutex;