feat: ws client (#394)

examples/ws.ts

@@ -1,39 +0,0 @@
-// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-import { serve } from "https://deno.land/std/http/mod.ts";
-import {
-  acceptWebSocket,
-  isWebSocketCloseEvent,
-  isWebSocketPingEvent
-} from "https://deno.land/std/ws/mod.ts";
-
-async function main(): Promise<void> {
-  console.log("websocket server is running on 0.0.0.0:8080");
-  for await (const req of serve("0.0.0.0:8080")) {
-    if (req.url === "/ws") {
-      (async (): Promise<void> => {
-        const sock = await acceptWebSocket(req);
-        console.log("socket connected!");
-        for await (const ev of sock.receive()) {
-          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);
-          }
-        }
-      })();
-    }
-  }
-}
-
-main();

io/bufio.ts

@@ -33,6 +33,11 @@ export class BufReader implements Reader {
   private lastCharSize: number;
   private err: BufState;
 
+  /** return new BufReader unless r is BufReader */
+  static create(r: Reader, size = DEFAULT_BUF_SIZE): BufReader {
+    return r instanceof BufReader ? r : new BufReader(r, size);
+  }
+
   constructor(rd: Reader, size = DEFAULT_BUF_SIZE) {
     if (size < MIN_BUF_SIZE) {
       size = MIN_BUF_SIZE;
@@ -368,6 +373,11 @@ export class BufWriter implements Writer {
   n: number = 0;
   err: null | BufState = null;
 
+  /** return new BufWriter unless w is BufWriter */
+  static create(w: Writer, size = DEFAULT_BUF_SIZE): BufWriter {
+    return w instanceof BufWriter ? w : new BufWriter(w, size);
+  }
+
   constructor(private wr: Writer, size = DEFAULT_BUF_SIZE) {
     if (size <= 0) {
       size = DEFAULT_BUF_SIZE;

ws/example_client.ts

@@ -0,0 +1,55 @@
+import {
+  connectWebSocket,
+  isWebSocketCloseEvent,
+  isWebSocketPingEvent,
+  isWebSocketPongEvent
+} from "../ws/mod.ts";
+import { encode } from "../strings/strings.ts";
+import { BufReader } from "../io/bufio.ts";
+import { TextProtoReader } from "../textproto/mod.ts";
+import { blue, green, red, yellow } from "../colors/mod.ts";
+
+const endpoint = Deno.args[1] || "ws://127.0.0.1:8080";
+/** simple websocket cli */
+async function main(): Promise<void> {
+  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);
+}
+
+if (import.meta.main) {
+  main();
+}

ws/example_server.ts

@@ -0,0 +1,66 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { serve } from "../http/server.ts";
+import {
+  acceptWebSocket,
+  isWebSocketCloseEvent,
+  isWebSocketPingEvent,
+  WebSocket
+} from "./mod.ts";
+
+/** websocket echo server */
+const port = Deno.args[1] || "8080";
+async function main(): Promise<void> {
+  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}`);
+        }
+      );
+  }
+}
+
+if (import.meta.main) {
+  main();
+}

ws/mod.ts

@@ -1,11 +1,14 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-const { Buffer } = Deno;
+
+import { decode, encode } from "../strings/strings.ts";
+
 type Conn = Deno.Conn;
 type Writer = Deno.Writer;
 import { BufReader, BufWriter } from "../io/bufio.ts";
 import { readLong, readShort, sliceLongToBytes } from "../io/ioutil.ts";
 import { Sha1 } from "./sha1.ts";
 import { writeResponse } from "../http/server.ts";
+import { TextProtoReader } from "../textproto/mod.ts";
 
 export enum OpCode {
   Continue = 0x0,
@@ -70,13 +73,19 @@ export interface WebSocketFrame {
 }
 
 export interface WebSocket {
+  readonly conn: Conn;
   readonly isClosed: boolean;
+
   receive(): AsyncIterableIterator<WebSocketEvent>;
+
   send(data: WebSocketMessage): Promise<void>;
+
   ping(data?: WebSocketMessage): Promise<void>;
+
   close(code: number, reason?: string): Promise<void>;
 }
 
+/** Unmask masked websocket payload */
 export function unmask(payload: Uint8Array, mask?: Uint8Array): void {
   if (mask) {
     for (let i = 0, len = payload.length; i < len; i++) {
@@ -85,6 +94,7 @@ export function unmask(payload: Uint8Array, mask?: Uint8Array): void {
   }
 }
 
+/** Write websocket frame to given writer */
 export async function writeFrame(
   frame: WebSocketFrame,
   writer: Writer
@@ -92,6 +102,11 @@ export async function writeFrame(
   const payloadLength = frame.payload.byteLength;
   let header: Uint8Array;
   const hasMask = frame.mask ? 0x80 : 0;
+  if (frame.mask && frame.mask.byteLength !== 4) {
+    throw new Error(
+      "invalid mask. mask must be 4 bytes: length=" + frame.mask.byteLength
+    );
+  }
   if (payloadLength < 126) {
     header = new Uint8Array([0x80 | frame.opcode, hasMask | payloadLength]);
   } else if (payloadLength < 0xffff) {
@@ -108,13 +123,18 @@ export async function writeFrame(
       ...sliceLongToBytes(payloadLength)
     ]);
   }
+  if (frame.mask) {
+    header = append(header, frame.mask);
+  }
   unmask(frame.payload, frame.mask);
-  const bytes = append(header, frame.payload);
+  header = append(header, frame.payload);
-  const w = new BufWriter(writer);
+  const w = BufWriter.create(writer);
-  await w.write(bytes);
+  await w.write(header);
-  await w.flush();
+  const err = await w.flush();
+  if (err) throw err;
 }
 
+/** Read websocket frame from given BufReader */
 export async function readFrame(buf: BufReader): Promise<WebSocketFrame> {
   let b = await buf.readByte();
   let isLastFrame = false;
@@ -155,62 +175,38 @@ export async function readFrame(buf: BufReader): Promise<WebSocketFrame> {
   };
 }
 
-export async function* receiveFrame(
+// Create client-to-server mask, random 32bit number
-  conn: Conn
+function createMask(): Uint8Array {
-): AsyncIterableIterator<WebSocketFrame> {
+  // TODO: use secure and immutable random function. Crypto.getRandomValues()
-  let receiving = true;
+  const arr = Array.from({ length: 4 }).map(
-  const isLastFrame = true;
+    (): number => Math.round(Math.random() * 0xff)
-  const reader = new BufReader(conn);
+  );
-  while (receiving) {
+  return new Uint8Array(arr);
-    const frame = await readFrame(reader);
-    const { opcode, payload } = frame;
-    switch (opcode) {
-      case OpCode.TextFrame:
-      case OpCode.BinaryFrame:
-      case OpCode.Continue:
-        yield frame;
-        break;
-      case OpCode.Close:
-        await writeFrame(
-          {
-            opcode,
-            payload,
-            isLastFrame
-          },
-          conn
-        );
-        conn.close();
-        yield frame;
-        receiving = false;
-        break;
-      case OpCode.Ping:
-        await writeFrame(
-          {
-            payload,
-            isLastFrame,
-            opcode: OpCode.Pong
-          },
-          conn
-        );
-        yield frame;
-        break;
-      case OpCode.Pong:
-        yield frame;
-        break;
-      default:
-    }
-  }
 }
 
 class WebSocketImpl implements WebSocket {
-  encoder = new TextEncoder();
+  private readonly mask?: Uint8Array;
+  private readonly bufReader: BufReader;
+  private readonly bufWriter: BufWriter;
 
-  constructor(private conn: Conn, private mask?: Uint8Array) {}
+  constructor(
+    readonly conn: Conn,
+    opts: {
+      bufReader?: BufReader;
+      bufWriter?: BufWriter;
+      mask?: Uint8Array;
+    } = {}
+  ) {
+    this.mask = opts.mask || createMask();
+    this.bufReader = opts.bufReader || new BufReader(conn);
+    this.bufWriter = opts.bufWriter || new BufWriter(conn);
+  }
 
   async *receive(): AsyncIterableIterator<WebSocketEvent> {
     let frames: WebSocketFrame[] = [];
     let payloadsLength = 0;
-    for await (const frame of receiveFrame(this.conn)) {
+    while (true) {
+      const frame = await readFrame(this.bufReader);
       unmask(frame.payload, frame.mask);
       switch (frame.opcode) {
         case OpCode.TextFrame:
@@ -227,7 +223,7 @@ class WebSocketImpl implements WebSocket {
             }
             if (frames[0].opcode === OpCode.TextFrame) {
               // text
-              yield new Buffer(concat).toString();
+              yield decode(concat);
             } else {
               // binary
               yield concat;
@@ -237,14 +233,23 @@ class WebSocketImpl implements WebSocket {
           }
           break;
         case OpCode.Close:
-          const code = (frame.payload[0] << 16) | frame.payload[1];
+          // [0x12, 0x34] -> 0x1234
-          const reason = new Buffer(
+          const code = (frame.payload[0] << 8) | frame.payload[1];
+          const reason = decode(
             frame.payload.subarray(2, frame.payload.length)
-          ).toString();
+          );
-          this._isClosed = true;
+          await this.close(code, reason);
           yield { code, reason };
           return;
         case OpCode.Ping:
+          await writeFrame(
+            {
+              opcode: OpCode.Pong,
+              payload: frame.payload,
+              isLastFrame: true
+            },
+            this.bufWriter
+          );
           yield ["ping", frame.payload] as WebSocketPingEvent;
           break;
         case OpCode.Pong:
@@ -261,7 +266,7 @@ class WebSocketImpl implements WebSocket {
     }
     const opcode =
       typeof data === "string" ? OpCode.TextFrame : OpCode.BinaryFrame;
-    const payload = typeof data === "string" ? this.encoder.encode(data) : data;
+    const payload = typeof data === "string" ? encode(data) : data;
     const isLastFrame = true;
     await writeFrame(
       {
@@ -270,20 +275,20 @@ class WebSocketImpl implements WebSocket {
         payload,
         mask: this.mask
       },
-      this.conn
+      this.bufWriter
     );
   }
 
-  async ping(data: WebSocketMessage): Promise<void> {
+  async ping(data: WebSocketMessage = ""): Promise<void> {
-    const payload = typeof data === "string" ? this.encoder.encode(data) : data;
+    const payload = typeof data === "string" ? encode(data) : data;
     await writeFrame(
       {
         isLastFrame: true,
-        opcode: OpCode.Close,
+        opcode: OpCode.Ping,
         mask: this.mask,
         payload
       },
-      this.conn
+      this.bufWriter
     );
   }
 
@@ -297,7 +302,7 @@ class WebSocketImpl implements WebSocket {
       const header = [code >>> 8, code & 0x00ff];
       let payload: Uint8Array;
       if (reason) {
-        const reasonBytes = this.encoder.encode(reason);
+        const reasonBytes = encode(reason);
         payload = new Uint8Array(2 + reasonBytes.byteLength);
         payload.set(header);
         payload.set(reasonBytes, 2);
@@ -311,7 +316,7 @@ class WebSocketImpl implements WebSocket {
           mask: this.mask,
           payload
         },
-        this.conn
+        this.bufWriter
       );
     } catch (e) {
       throw e;
@@ -320,11 +325,10 @@ class WebSocketImpl implements WebSocket {
     }
   }
 
-  private ensureSocketClosed(): Error {
+  private ensureSocketClosed(): void {
     if (this.isClosed) {
       return;
     }
-
     try {
       this.conn.close();
     } catch (e) {
@@ -335,16 +339,20 @@ class WebSocketImpl implements WebSocket {
   }
 }
 
+/** Return whether given headers is acceptable for websocket  */
 export function acceptable(req: { headers: Headers }): boolean {
+  const secKey = req.headers.get("sec-websocket-key");
   return (
     req.headers.get("upgrade") === "websocket" &&
     req.headers.has("sec-websocket-key") &&
-    req.headers.get("sec-websocket-key").length > 0
+    typeof secKey === "string" &&
+    secKey.length > 0
   );
 }
 
 const kGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 
+/** Create sec-websocket-accept header value with given nonce */
 export function createSecAccept(nonce: string): string {
   const sha1 = new Sha1();
   sha1.update(nonce + kGUID);
@@ -352,16 +360,22 @@ export function createSecAccept(nonce: string): string {
   return btoa(String.fromCharCode.apply(String, bytes));
 }
 
+/** Upgrade given TCP connection into websocket connection */
 export async function acceptWebSocket(req: {
   conn: Conn;
+  bufWriter: BufWriter;
+  bufReader: BufReader;
   headers: Headers;
 }): Promise<WebSocket> {
-  const { conn, headers } = req;
+  const { conn, headers, bufReader, bufWriter } = req;
   if (acceptable(req)) {
-    const sock = new WebSocketImpl(conn);
+    const sock = new WebSocketImpl(conn, { bufReader, bufWriter });
     const secKey = headers.get("sec-websocket-key");
+    if (typeof secKey !== "string") {
+      throw new Error("sec-websocket-key is not provided");
+    }
     const secAccept = createSecAccept(secKey);
-    await writeResponse(conn, {
+    await writeResponse(bufWriter, {
       status: 101,
       headers: new Headers({
         Upgrade: "websocket",
@@ -373,3 +387,94 @@ export async function acceptWebSocket(req: {
   }
   throw new Error("request is not acceptable");
 }
+
+const kSecChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-.~_";
+
+/** Create WebSocket-Sec-Key. Base64 encoded 16 bytes string */
+export function createSecKey(): string {
+  let key = "";
+  for (let i = 0; i < 16; i++) {
+    const j = Math.round(Math.random() * kSecChars.length);
+    key += kSecChars[j];
+  }
+  return btoa(key);
+}
+
+/** Connect to given websocket endpoint url. Endpoint must be acceptable for URL */
+export async function connectWebSocket(
+  endpoint: string,
+  headers: Headers = new Headers()
+): Promise<WebSocket> {
+  const url = new URL(endpoint);
+  const { hostname, pathname, searchParams } = url;
+  let port = url.port;
+  if (!url.port) {
+    if (url.protocol === "http" || url.protocol === "ws") {
+      port = "80";
+    } else if (url.protocol === "https" || url.protocol === "wss") {
+      throw new Error("currently https/wss is not supported");
+    }
+  }
+  const conn = await Deno.dial("tcp", `${hostname}:${port}`);
+  const abortHandshake = (err: Error): void => {
+    conn.close();
+    throw err;
+  };
+  const bufWriter = new BufWriter(conn);
+  const bufReader = new BufReader(conn);
+  await bufWriter.write(
+    encode(`GET ${pathname}?${searchParams || ""} HTTP/1.1\r\n`)
+  );
+  const key = createSecKey();
+  if (!headers.has("host")) {
+    headers.set("host", hostname);
+  }
+  headers.set("upgrade", "websocket");
+  headers.set("connection", "upgrade");
+  headers.set("sec-websocket-key", key);
+  let headerStr = "";
+  for (const [key, value] of headers) {
+    headerStr += `${key}: ${value}\r\n`;
+  }
+  headerStr += "\r\n";
+  await bufWriter.write(encode(headerStr));
+  let err, statusLine, responseHeaders;
+  err = await bufWriter.flush();
+  if (err) {
+    throw new Error("ws: failed to send handshake: " + err);
+  }
+  const tpReader = new TextProtoReader(bufReader);
+  [statusLine, err] = await tpReader.readLine();
+  if (err) {
+    abortHandshake(new Error("ws: failed to read status line: " + err));
+  }
+  const m = statusLine.match(/^(.+?) (.+?) (.+?)$/);
+  if (!m) {
+    abortHandshake(new Error("ws: invalid status line: " + statusLine));
+  }
+  const [_, version, statusCode] = m;
+  if (version !== "HTTP/1.1" || statusCode !== "101") {
+    abortHandshake(
+      new Error(
+        `ws: server didn't accept handshake: version=${version}, statusCode=${statusCode}`
+      )
+    );
+  }
+  [responseHeaders, err] = await tpReader.readMIMEHeader();
+  if (err) {
+    abortHandshake(new Error("ws: failed to parse response headers: " + err));
+  }
+  const expectedSecAccept = createSecAccept(key);
+  const secAccept = responseHeaders.get("sec-websocket-accept");
+  if (secAccept !== expectedSecAccept) {
+    abortHandshake(
+      new Error(
+        `ws: unexpected sec-websocket-accept header: expected=${expectedSecAccept}, actual=${secAccept}`
+      )
+    );
+  }
+  return new WebSocketImpl(conn, {
+    bufWriter,
+    bufReader
+  });
+}

ws/test.ts

@@ -1,19 +1,21 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 import "./sha1_test.ts";
-
-const { Buffer } = Deno;
 import { BufReader } from "../io/bufio.ts";
 import { assert, assertEquals } from "../testing/asserts.ts";
-import { test } from "../testing/mod.ts";
+import { runIfMain, test } from "../testing/mod.ts";
 import {
   acceptable,
   createSecAccept,
   OpCode,
   readFrame,
-  unmask
+  unmask,
+  writeFrame
 } from "./mod.ts";
+import { encode } from "../strings/strings.ts";
 
-test(async function testReadUnmaskedTextFrame(): Promise<void> {
+const { Buffer } = Deno;
+
+test(async function wsReadUnmaskedTextFrame(): Promise<void> {
   // unmasked single text frame with payload "Hello"
   const buf = new BufReader(
     new Buffer(new Uint8Array([0x81, 0x05, 0x48, 0x65, 0x6c, 0x6c, 0x6f]))
@@ -25,7 +27,7 @@ test(async function testReadUnmaskedTextFrame(): Promise<void> {
   assertEquals(frame.isLastFrame, true);
 });
 
-test(async function testReadMakedTextFrame(): Promise<void> {
+test(async function wsReadMaskedTextFrame(): Promise<void> {
   //a masked single text frame with payload "Hello"
   const buf = new BufReader(
     new Buffer(
@@ -52,7 +54,7 @@ test(async function testReadMakedTextFrame(): Promise<void> {
   assertEquals(frame.isLastFrame, true);
 });
 
-test(async function testReadUnmaskedSplittedTextFrames(): Promise<void> {
+test(async function wsReadUnmaskedSplitTextFrames(): Promise<void> {
   const buf1 = new BufReader(
     new Buffer(new Uint8Array([0x01, 0x03, 0x48, 0x65, 0x6c]))
   );
@@ -71,7 +73,7 @@ test(async function testReadUnmaskedSplittedTextFrames(): Promise<void> {
   assertEquals(new Buffer(f2.payload).toString(), "lo");
 });
 
-test(async function testReadUnmaksedPingPongFrame(): Promise<void> {
+test(async function wsReadUnmaskedPingPongFrame(): Promise<void> {
   // unmasked ping with payload "Hello"
   const buf = new BufReader(
     new Buffer(new Uint8Array([0x89, 0x05, 0x48, 0x65, 0x6c, 0x6c, 0x6f]))
@@ -104,7 +106,7 @@ test(async function testReadUnmaksedPingPongFrame(): Promise<void> {
   assertEquals(new Buffer(pong.payload).toString(), "Hello");
 });
 
-test(async function testReadUnmaksedBigBinaryFrame(): Promise<void> {
+test(async function wsReadUnmaskedBigBinaryFrame(): Promise<void> {
   const a = [0x82, 0x7e, 0x01, 0x00];
   for (let i = 0; i < 256; i++) {
     a.push(i);
@@ -117,7 +119,7 @@ test(async function testReadUnmaksedBigBinaryFrame(): Promise<void> {
   assertEquals(bin.payload.length, 256);
 });
 
-test(async function testReadUnmaskedBigBigBinaryFrame(): Promise<void> {
+test(async function wsReadUnmaskedBigBigBinaryFrame(): Promise<void> {
   const a = [0x82, 0x7f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00];
   for (let i = 0; i < 0xffff; i++) {
     a.push(i);
@@ -130,13 +132,13 @@ test(async function testReadUnmaskedBigBigBinaryFrame(): Promise<void> {
   assertEquals(bin.payload.length, 0xffff + 1);
 });
 
-test(async function testCreateSecAccept(): Promise<void> {
+test(async function wsCreateSecAccept(): Promise<void> {
   const nonce = "dGhlIHNhbXBsZSBub25jZQ==";
   const d = createSecAccept(nonce);
   assertEquals(d, "s3pPLMBiTxaQ9kYGzzhZRbK+xOo=");
 });
 
-test(function testAcceptable(): void {
+test(function wsAcceptable(): void {
   const ret = acceptable({
     headers: new Headers({
       upgrade: "websocket",
@@ -153,7 +155,7 @@ const invalidHeaders = [
   { upgrade: "websocket", "sec-websocket-ky": "" }
 ];
 
-test(function testAcceptableInvalid(): void {
+test(function wsAcceptableInvalid(): void {
   for (const pat of invalidHeaders) {
     const ret = acceptable({
       headers: new Headers(pat)
@@ -161,3 +163,27 @@ test(function testAcceptableInvalid(): void {
     assertEquals(ret, false);
   }
 });
+
+test(async function wsWriteReadMaskedFrame(): Promise<void> {
+  const mask = new Uint8Array([0, 1, 2, 3]);
+  const msg = "hello";
+  const buf = new Buffer();
+  const r = new BufReader(buf);
+  await writeFrame(
+    {
+      isLastFrame: true,
+      mask,
+      opcode: OpCode.TextFrame,
+      payload: encode(msg)
+    },
+    buf
+  );
+  const frame = await readFrame(r);
+  assertEquals(frame.opcode, OpCode.TextFrame);
+  assertEquals(frame.isLastFrame, true);
+  assertEquals(frame.mask, mask);
+  unmask(frame.payload, frame.mask);
+  assertEquals(frame.payload, encode(msg));
+});
+
+runIfMain(import.meta);