server.c File Reference

WebSocket server implementation. More...

Go to the source code of this file.

Data Structures
struct	websocket_connection_data_t
	Per-connection user data. More...

Functions
asciichat_error_t	websocket_server_init (websocket_server_t *server, const websocket_server_config_t *config)
asciichat_error_t	websocket_server_run (websocket_server_t *server)
void	websocket_server_cancel_service (websocket_server_t *server)
void	websocket_server_destroy (websocket_server_t *server)

Detailed Description

WebSocket server implementation.

Author

Zachary Fogg me@zf.nosp@m.o.gg

Date

February 2026

Definition in file lib/network/websocket/server.c.

Function Documentation

websocket_server_cancel_service()

void websocket_server_cancel_service

(

websocket_server_t *

server

)

Definition at line 880 of file lib/network/websocket/server.c.

                                                                 {
  if (server && server->context) {
    lws_cancel_service(server->context);
  }
}

Referenced by server_main().

websocket_server_destroy()

void websocket_server_destroy

(

websocket_server_t *

server

)

Definition at line 886 of file lib/network/websocket/server.c.

                                                          {
  if (!server) {
    return;
  }
 
  atomic_store(&server->running, false);
 
  // Context is normally destroyed by websocket_server_run (from the event loop
  // thread) for fast shutdown. This handles the case where run() wasn't called
  // or didn't complete normally.
  if (server->context) {
    log_debug("WebSocket context still alive in destroy, cleaning up");
    lws_context_destroy(server->context);
    server->context = NULL;
  }
 
  log_debug("WebSocket server destroyed");
}

Referenced by acds_main(), and server_main().

websocket_server_init()

asciichat_error_t websocket_server_init	(	websocket_server_t *	server,
		const websocket_server_config_t *	config
	)

Definition at line 791 of file lib/network/websocket/server.c.

                                                                                                             {
  if (!server || !config || !config->client_handler) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Invalid parameters");
  }
 
  memset(server, 0, sizeof(*server));
  server->handler = config->client_handler;
  server->user_data = config->user_data;
  server->port = config->port;
  atomic_store(&server->running, true);
 
  // Store server pointer in protocol user data so callbacks can access it
  // Both the HTTP and ACIP protocols need access to the server
  websocket_protocols[0].user = server; // http protocol
  websocket_protocols[1].user = server; // acip protocol
 
  // Enable libwebsockets debug logging with custom callback
  lws_set_log_level(LLL_ERR | LLL_WARN | LLL_NOTICE | LLL_INFO | LLL_DEBUG, websocket_lws_log_callback);
 
  // Configure libwebsockets context
  struct lws_context_creation_info info = {0};
  info.port = config->port;
  info.protocols = websocket_protocols;
  info.gid = (gid_t)-1;   // Cast to avoid undefined behavior with unsigned type
  info.uid = (uid_t)-1;   // Cast to avoid undefined behavior with unsigned type
  info.options = 0;       // Don't validate UTF8 - we send binary ACIP packets
  info.extensions = NULL; // Disable permessage-deflate - causes rx buffer underflow in LWS 4.5.2
  // TODO: Re-enable compression with proper LWS configuration if needed for bandwidth optimization
  // Current issue: Even with server_max_window_bits=11, large fragmented messages still trigger
  // "lws_extension_callback_pm_deflate: rx buffer underflow" errors in LWS 4.5.2
 
  // Create libwebsockets context
  server->context = lws_create_context(&info);
  if (!server->context) {
    return SET_ERRNO(ERROR_NETWORK_BIND, "Failed to create libwebsockets context");
  }
 
  log_info("WebSocket server initialized on port %d with static file serving", config->port);
  return ASCIICHAT_OK;
}

Referenced by acds_main(), and server_main().

websocket_server_run()

asciichat_error_t websocket_server_run

(

websocket_server_t *

server

)

Definition at line 832 of file lib/network/websocket/server.c.

                                                                   {
  if (!server || !server->context) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Invalid server");
  }
 
  log_info("WebSocket server starting event loop on port %d", server->port);
 
  // Run libwebsockets event loop
  uint64_t last_service_ns = 0;
  int service_call_count = 0;
  while (atomic_load(&server->running)) {
    // Service libwebsockets with 50ms timeout.
    // This provides frequent event processing (~20 callback invocations per second) for all
    // connected WebSocket clients while avoiding excessive CPU usage from polling.
    // All client connections share this single server context, so a single lws_service() call
    // services fragments and events for all clients simultaneously.
    uint64_t service_start_ns = time_get_ns();
    if (last_service_ns && service_start_ns - last_service_ns > 30 * US_PER_MS_INT) {
      // > 30ms gap between service calls
      double gap_ms = (double)(service_start_ns - last_service_ns) / 1e6;
      log_info_every(1 * US_PER_MS_INT, "[LWS_SERVICE_GAP] %.1fms gap between lws_service calls", gap_ms);
    }
    service_call_count++;
    log_debug_every(500 * US_PER_MS_INT, "[LWS_SERVICE] Call #%d, context=%p", service_call_count,
                    (void *)server->context);
    int result = lws_service(server->context, 50);
    if (result < 0) {
      log_error("libwebsockets service error: %d", result);
      break;
    }
  }
 
  log_info("WebSocket server event loop exited, destroying context from event loop thread");
 
  // Destroy context from the event loop thread. When called from a different
  // thread after the event loop has stopped, lws_context_destroy tries to
  // gracefully close WebSocket connections but can't process close responses
  // (no event loop running), so it waits for the close handshake timeout
  // (5+ seconds). Destroying from the event loop thread avoids this.
  if (server->context) {
    lws_context_destroy(server->context);
    server->context = NULL;
  }
 
  log_info("WebSocket server context destroyed");
  return ASCIICHAT_OK;
}

References time_get_ns().