denoland-deno/std/ws/example_server.ts

// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
import { serve } from "../http/server.ts";
import {
  acceptWebSocket,
  isWebSocketCloseEvent,
  isWebSocketPingEvent,
} from "./mod.ts";

/** websocket echo server */
const port = Deno.args[0] || "8080";
console.log(`websocket server is running on :${port}`);
for await (const req of serve(`:${port}`)) {
  const { conn, r: bufReader, w: bufWriter, headers } = req;

  try {
    const sock = await acceptWebSocket({
      conn,
      bufReader,
      bufWriter,
      headers,
    });

    console.log("socket connected!");

    try {
      for await (const ev of sock) {
        if (typeof ev === "string") {
          // text message
          console.log("ws:Text", ev);
          await sock.send(ev);
        } else if (ev instanceof Uint8Array) {
          // binary message
          console.log("ws:Binary", ev);
        } else if (isWebSocketPingEvent(ev)) {
          const [, body] = ev;
          // ping
          console.log("ws:Ping", body);
        } else if (isWebSocketCloseEvent(ev)) {
          // close
          const { code, reason } = ev;
          console.log("ws:Close", code, reason);
        }
      }
    } catch (err) {
      console.error(`failed to receive frame: ${err}`);

      if (!sock.isClosed) {
        await sock.close(1000).catch(console.error);
      }
    }
  } catch (err) {
    console.error(`failed to accept websocket: ${err}`);
    await req.respond({ status: 400 });
  }
}