/* We simply call the root header file "App.h", giving you uWS::App and uWS::SSLApp */ #include "App.h" /* This is a simple WebSocket "async" upgrade example. * You may compile it with "WITH_OPENSSL=1 make" or with "make" */ int main() { /* ws->getUserData returns one of these */ struct PerSocketData { /* Define your user data */ int something; }; /* Keep in mind that uWS::SSLApp({options}) is the same as uWS::App() when compiled without SSL support. * You may swap to using uWS:App() if you don't need SSL */ uWS::SSLApp({ /* There are example certificates in uWebSockets.js repo */ .key_file_name = "misc/key.pem", .cert_file_name = "misc/cert.pem", .passphrase = "1234" }).ws("/*", { /* Settings */ .compression = uWS::SHARED_COMPRESSOR, .maxPayloadLength = 16 * 1024, .idleTimeout = 10, .maxBackpressure = 1 * 1024 * 1024, /* Handlers */ .upgrade = [](auto *res, auto *req, auto *context) { /* HttpRequest (req) is only valid in this very callback, so we must COPY the headers * we need later on while upgrading to WebSocket. You must not access req after first return. * Here we create a heap allocated struct holding everything we will need later on. */ struct UpgradeData { std::string secWebSocketKey; std::string secWebSocketProtocol; std::string secWebSocketExtensions; struct us_socket_context_t *context; decltype(res) httpRes; bool aborted = false; } *upgradeData = new UpgradeData { std::string(req->getHeader("sec-websocket-key")), std::string(req->getHeader("sec-websocket-protocol")), std::string(req->getHeader("sec-websocket-extensions")), context, res }; /* We have to attach an abort handler for us to be aware * of disconnections while we perform async tasks */ res->onAborted([=]() { /* We don't implement any kind of cancellation here, * so simply flag us as aborted */ upgradeData->aborted = true; std::cout << "HTTP socket was closed before we upgraded it!" << std::endl; }); /* Simulate checking auth for 5 seconds. This looks like crap, never write * code that utilize us_timer_t like this; they are high-cost and should * not be created and destroyed more than rarely! * * Also note that the code would be a lot simpler with capturing lambdas, maybe your * database client has such a nice interface? Either way, here we go!*/ struct us_loop_t *loop = (struct us_loop_t *) uWS::Loop::get(); struct us_timer_t *delayTimer = us_create_timer(loop, 0, sizeof(UpgradeData *)); memcpy(us_timer_ext(delayTimer), &upgradeData, sizeof(UpgradeData *)); us_timer_set(delayTimer, [](struct us_timer_t *t) { /* We wrote the upgradeData pointer to the timer's extension */ UpgradeData *upgradeData; memcpy(&upgradeData, us_timer_ext(t), sizeof(UpgradeData *)); /* Were'nt we aborted before our async task finished? Okay, upgrade then! */ if (!upgradeData->aborted) { std::cout << "Async task done, upgrading to WebSocket now!" << std::endl; /* If you don't want to upgrade you can instead respond with custom HTTP here, * such as res->writeStatus(...)->writeHeader(...)->end(...); or similar.*/ /* This call will immediately emit .open event */ upgradeData->httpRes->cork([upgradeData]() { upgradeData->httpRes->template upgrade({ /* We initialize PerSocketData struct here */ .something = 13 }, upgradeData->secWebSocketKey, upgradeData->secWebSocketProtocol, upgradeData->secWebSocketExtensions, upgradeData->context); }); } else { std::cout << "Async task done, but the HTTP socket was closed. Skipping upgrade to WebSocket!" << std::endl; } delete upgradeData; us_timer_close(t); }, 5000, 0); }, .open = [](auto *ws) { /* Open event here, you may access ws->getUserData() which points to a PerSocketData struct. * Here we simply validate that indeed, something == 13 as set in upgrade handler. */ std::cout << "Something is: " << static_cast(ws->getUserData())->something << std::endl; }, .message = [](auto *ws, std::string_view message, uWS::OpCode opCode) { /* We simply echo whatever data we get */ ws->send(message, opCode); }, .drain = [](auto */*ws*/) { /* Check ws->getBufferedAmount() here */ }, .ping = [](auto */*ws*/, std::string_view) { /* You don't need to handle this one, we automatically respond to pings as per standard */ }, .pong = [](auto */*ws*/, std::string_view) { /* You don't need to handle this one either */ }, .close = [](auto */*ws*/, int /*code*/, std::string_view /*message*/) { /* You may access ws->getUserData() here, but sending or * doing any kind of I/O with the socket is not valid. */ } }).listen(9001, [](auto *listen_socket) { if (listen_socket) { std::cout << "Listening on port " << 9001 << std::endl; } }).run(); }