yhirose
9bfd2ddf1c
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.
2.1 KiB
title, order, status
| title | order | status |
|---|---|---|
| S09. Add Pre-Processing to All Routes | 28 | draft |
Sometimes you want the same logic to run before every request — auth checks, logging, rate limiting. Register those with set_pre_routing_handler().
Basic usage
svr.set_pre_routing_handler(
[](const httplib::Request &req, httplib::Response &res) {
std::cout << req.method << " " << req.path << std::endl;
return httplib::Server::HandlerResponse::Unhandled;
});
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.
The HandlerResponse return value is key:
- Return
Unhandled→ continue normally (routing and the actual handler run) - Return
Handled→ the response is considered complete, skip the rest
Use it for authentication
Put your shared auth check in one place.
svr.set_pre_routing_handler(
[](const httplib::Request &req, httplib::Response &res) {
if (req.path.rfind("/public", 0) == 0) {
return httplib::Server::HandlerResponse::Unhandled; // no auth needed
}
auto auth = req.get_header_value("Authorization");
if (auth.empty()) {
res.status = 401;
res.set_content("unauthorized", "text/plain");
return httplib::Server::HandlerResponse::Handled;
}
return httplib::Server::HandlerResponse::Unhandled;
});
If auth fails, return Handled to respond with 401 immediately. If it passes, return Unhandled and let routing take over.
For per-route auth
If you want different auth rules per route rather than a single global check, set_pre_request_handler() is a better fit. See S11. Authenticate per route with a pre-request handler.
Note: If all you want is to modify the response,
set_post_routing_handler()is the right tool. See S10. Add response headers with a post-routing handler.