denoland-deno/std/ws

ws

ws module is made to provide helpers to create WebSocket client/server.

Usage

Server

import { serve } from "https://deno.land/std/http/server.ts";
import {
  acceptWebSocket,
  isWebSocketCloseEvent,
  isWebSocketPingEvent,
  WebSocket
} from "https://deno.land/std/ws/mod.ts";

/** websocket echo server */
const port = Deno.args[1] || "8080";
console.log(`websocket server is running on :${port}`);
for await (const req of serve(`:${port}`)) {
  const { headers, conn } = req;
  acceptWebSocket({
    conn,
    headers,
    bufReader: req.r,
    bufWriter: req.w
  })
    .then(
      async (sock: WebSocket): Promise<void> => {
        console.log("socket connected!");
        const it = sock.receive();
        while (true) {
          try {
            const { done, value } = await it.next();
            if (done) {
              break;
            }
            const ev = value;
            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 (e) {
            console.error(`failed to receive frame: ${e}`);
            await sock.close(1000).catch(console.error);
          }
        }
      }
    )
    .catch(
      (err: Error): void => {
        console.error(`failed to accept websocket: ${err}`);
      }
    );
}

Client

import {
  connectWebSocket,
  isWebSocketCloseEvent,
  isWebSocketPingEvent,
  isWebSocketPongEvent
} from "https://deno.land/std/ws/mod.ts";
import { encode } from "https://deno.land/std/strings/mod.ts";
import { BufReader } from "https://deno.land/std/io/bufio.ts";
import { TextProtoReader } from "https://deno.land/std/textproto/mod.ts";
import { blue, green, red, yellow } from "https://deno.land/std/fmt/colors.ts";

const endpoint = Deno.args[1] || "ws://127.0.0.1:8080";
/** simple websocket cli */
const sock = await connectWebSocket(endpoint);
console.log(green("ws connected! (type 'close' to quit)"));
(async function(): Promise<void> {
  for await (const msg of sock.receive()) {
    if (typeof msg === "string") {
      console.log(yellow("< " + msg));
    } else if (isWebSocketPingEvent(msg)) {
      console.log(blue("< ping"));
    } else if (isWebSocketPongEvent(msg)) {
      console.log(blue("< pong"));
    } else if (isWebSocketCloseEvent(msg)) {
      console.log(red(`closed: code=${msg.code}, reason=${msg.reason}`));
    }
  }
})();

const tpr = new TextProtoReader(new BufReader(Deno.stdin));
while (true) {
  await Deno.stdout.write(encode("> "));
  const [line, err] = await tpr.readLine();
  if (err) {
    console.error(red(`failed to read line from stdin: ${err}`));
    break;
  }
  if (line === "close") {
    break;
  } else if (line === "ping") {
    await sock.ping();
  } else {
    await sock.send(line);
  }
  // FIXME: Without this,
  // sock.receive() won't resolved though it is readable...
  await new Promise(
    (resolve): void => {
      setTimeout(resolve, 0);
    }
  );
}
await sock.close(1000);
// FIXME: conn.close() won't shutdown process...
Deno.exit(0);

API

isWebSocketCloseEvent

Returns true if input value is a WebSocketCloseEvent, false otherwise.

isWebSocketPingEvent

Returns true if input value is a WebSocketPingEvent, false otherwise.

isWebSocketPongEvent

Returns true if input value is a WebSocketPongEvent, false otherwise.

append

This module is used to merge two Uint8Arrays.

• note: This module might move to common/util.

import { append } from "https://deno.land/std/ws/mod.ts";

// a = [1], b = [2]
append(a, b); // output: [1, 2]

// a = [1], b = null
append(a, b); // output: [1]

// a = [], b = [2]
append(a, b); // output: [2]

unmask

Unmask masked WebSocket payload.

writeFrame

Write WebSocket frame to inputted writer.

readFrame

Read WebSocket frame from inputted BufReader.

createMask

Create mask from the client to the server with random 32bit number.

acceptable

Returns true if input headers are usable for WebSocket, otherwise false

createSecAccept

Create value of Sec-WebSocket-Accept header from inputted nonce.

acceptWebSocket

Upgrade inputted TCP connection into WebSocket connection.

createSecKey

Returns base64 encoded 16 bytes string for Sec-WebSocket-Key header.

connectWebSocket

Connect to WebSocket endpoint url with inputted endpoint string and headers.

• note: Endpoint must be acceptable for URL.