Hello, HTTP/3

An HTTP/3 server is a request handler plus a server identity. This page answers every request with hello.

Code

main.c

#define WIRED_MAIN
#include "wired.h"

/* Called once per request (and again while *more is set). Fill body_out and
 * return 1 to answer 200. */
static int on_request(
    void*                       ctx,
    const wired_h3reqdrive_req* req,
    u64                         offset,
    wired_obuf*                 body_out,
    const char**                content_type,
    int*                        more,
    u64*                        total_size) {
  (void)ctx;
  (void)req;
  (void)offset;
  (void)more;
  (void)total_size;
  wired_log_str("request /\n");
  *content_type = "text/plain";
  wired_obuf_printf(body_out, "hello");
  return 1;
}

int wired_main(int argc, char** argv) {
  /* Fixed demo identity (self-signed certificate; never for production). */
  static wired_srvboot_demo_keys keys;
  wired_srvboot_id               id;
  wired_srvboot_demo(&id, &keys, 0x50, "guide-h3");

  u16 port                 = (u16)wired_cliargs_int(argc, argv, "--port", 4433);
  wired_srvrun_handler h   = {.cb = on_request};
  wired_srvrun_obs     obs = {0};
  return wired_server_run(port, &id, h, obs) ? 0 : 1;
}

Output

$ ./h3-hello --port 4433
request /
conn closed by peer (CONNECTION_CLOSE)

$ probe h3get 127.0.0.1:4433 /
GET / status=200 content-type=text/plain body="hello"

How it works

• wired_server_run(port, &id, h, obs) runs QUIC, TLS 1.3 and HTTP/3 on a UDP port and calls your handler once per request.
• wired_srvboot_id is the server identity: X25519 key pair, certificate signing seed, connection id and ServerHello.random. wired_srvboot_demo(&id, &keys, 0x50, "guide-h3") fills it with fixed demo bytes (a self-signed certificate; never use it in production). keys holds the key material id points at, so it is static.
• The handler writes the body into body_out, sets *content_type, and returns 1. Returning 0 sends a body-less 200.
• wired_cliargs_int reads --port from the command line.