Method sendFile

packages/socket.io/lib/index.ts:684–717

* @param filename * @param req * @param res * @private

(
    filename: string,
    req: IncomingMessage,
    res: ServerResponse,
  )

   * @private
   */
  private static sendFile(
    filename: string,
    req: IncomingMessage,
    res: ServerResponse,
  ): void {
    const readStream = createReadStream(
      path.join(__dirname, "../client-dist/", filename),
    );
    const encoding = accepts(req).encodings(["br", "gzip", "deflate"]);

    const onError = (err: NodeJS.ErrnoException | null) => {
      if (err) {
        res.end();
      }
    };

    switch (encoding) {
      case "br":
        res.writeHead(200, { "content-encoding": "br" });
        pipeline(readStream, createBrotliCompress(), res, onError);
        break;
      case "gzip":
        res.writeHead(200, { "content-encoding": "gzip" });
        pipeline(readStream, createGzip(), res, onError);
        break;
      case "deflate":
        res.writeHead(200, { "content-encoding": "deflate" });
        pipeline(readStream, createDeflate(), res, onError);
        break;
      default:
        res.writeHead(200);
        pipeline(readStream, res, onError);
    }
  }

  /**
   * Binds socket.io to an engine.io instance.