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";

if (import.meta.main) {
  /** 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 });
    }
  }
}