Method attachApp

packages/socket.io/lib/index.ts:523–584

* Attaches socket.io to a uWebSockets.js app. * @param app * @param opts

(app /*: TemplatedApp */, opts: Partial<ServerOptions> = {})

   * @param opts
   */
  public attachApp(app /*: TemplatedApp */, opts: Partial<ServerOptions> = {}) {
    // merge the options passed to the Socket.IO server
    Object.assign(opts, this.opts);
    // set engine.io path to `/socket.io`
    opts.path = opts.path || this._path;

    // initialize engine
    debug("creating uWebSockets.js-based engine with opts %j", opts);
    const engine = new uServer(opts);

    engine.attach(app, opts);

    // bind to engine events
    this.bind(engine);

    if (this._serveClient) {
      // attach static file serving
      app.get(`${this._path}/*`, (res, req) => {
        if (!this.clientPathRegex.test(req.getUrl())) {
          req.setYield(true);
          return;
        }

        const filename = req
          .getUrl()
          .replace(this._path, "")
          .replace(/\?.*$/, "")
          .replace(/^\//, "");
        const isMap = dotMapRegex.test(filename);
        const type = isMap ? "map" : "source";

        // Per the standard, ETags must be quoted:
        // https://tools.ietf.org/html/rfc7232#section-2.3
        const expectedEtag = '"' + clientVersion + '"';
        const weakEtag = "W/" + expectedEtag;

        const etag = req.getHeader("if-none-match");
        if (etag) {
          if (expectedEtag === etag || weakEtag === etag) {
            debug("serve client %s 304", type);
            res.writeStatus("304 Not Modified");
            res.end();
            return;
          }
        }

        debug("serve client %s", type);

        res.writeHeader("cache-control", "public, max-age=0");
        res.writeHeader(
          "content-type",
          "application/" + (isMap ? "json" : "javascript") + "; charset=utf-8",
        );
        res.writeHeader("etag", expectedEtag);

        const filepath = path.join(__dirname, "../client-dist/", filename);
        serveFile(res, filepath);
      });