Rationale: - It is not a part of eSpeak-NG, nor useful wrapper/adapter - It is not properly documented and maintained - It is unsafe (running PHP daemon with user privileges and [launch ANY](6d7101c03c/chromium_extension/index.php (L8)) received command via [passthru](https://www.php.net/manual/en/function.passthru.php) - seriously?)

2 years ago · 892651bb77
--- a/chromium_extension/AudioStream.js
+++ b/chromium_extension/AudioStream.js
 class AudioStream {
  constructor({ stdin, recorder = false }) {
    if (!/^espeak-ng/.test(stdin)) {
      throw new Error(`stdin should begin with "espeak-ng" command`);
    }
    this.command = stdin;
    this.stdin = new ReadableStream({
      start(c) {
        c.enqueue(
          new File([stdin], 'espeakng', {
            type: 'application/octet-stream',
          })
        );
        c.close();
      },
    });
    this.readOffset = 0;
    this.duration = 0;
    this.channelDataLength = 440;
    this.sampleRate = 22050;
    this.numberOfChannels = 1;
    this.init = false;
    this.src =
      'chrome-extension://<id>/nativeTransferableStream.html';
    this.ac = new AudioContext({
      latencyHint: 0,
    });
    this.ac.suspend();
    this.msd = new MediaStreamAudioDestinationNode(this.ac, {
      channelCount: this.numberOfChannels,
    });
    this.inputController = void 0;
    this.inputStream = new ReadableStream({
      start: (_) => {
        return (this.inputController = _);
      },
    });
    this.inputReader = this.inputStream.getReader();
    const { stream } = this.msd;
    this.stream = stream;
    const [track] = stream.getAudioTracks();
    this.track = track;
    this.osc = new OscillatorNode(this.ac, { frequency: 0 });
    this.processor = new MediaStreamTrackProcessor({ track });
    this.generator = new MediaStreamTrackGenerator({ kind: 'audio' });
    const { writable } = this.generator;
    this.writable = writable;
    const { readable: audioReadable } = this.processor;
    this.audioReadable = audioReadable;
    this.audioWriter = this.writable.getWriter();
    this.mediaStream = new MediaStream([this.generator]);
    if (recorder) {
      this.recorder = new MediaRecorder(this.mediaStream);
      this.recorder.ondataavailable = ({ data }) => {
        this.data = data;
      };
    }
    this.outputSource = new MediaStreamAudioSourceNode(this.ac, {
      mediaStream: this.mediaStream,
    });
    this.outputSource.connect(this.ac.destination);
    this.resolve = void 0;
    this.promise = new Promise((_) => (this.resolve = _));
    this.osc.connect(this.msd);
    this.osc.start();
    this.track.onmute = this.track.onunmute = this.track.onended = (e) =>
      console.log(e);
    this.abortable = new AbortController();
    const { signal } = this.abortable;
    this.signal = signal;
    this.audioReadableAbortable = new AbortController();
    const { signal: audioReadableSignal } = this.audioReadableAbortable;
    this.audioReadableSignal = audioReadableSignal;
    this.audioReadableSignal.onabort = (e) => console.log(e.type);
    this.abortHandler = async (e) => {
      try {
        await this.disconnect(true);
      } catch (err) {
        console.warn(err.message);
      }
      console.log(
        `readOffset:${this.readOffset}, duration:${this.duration}, ac.currentTime:${this.ac.currentTime}`,
        `generator.readyState:${this.generator.readyState}, audioWriter.desiredSize:${this.audioWriter.desiredSize}`,
        `inputController.desiredSize:${this.inputController.desiredSize}, ac.state:${this.ac.state}`
      );
      if (
        this.transferableWindow ||
        document.body.querySelector(`iframe[src="${this.src}"]`)
      ) {
        document.body.removeChild(this.transferableWindow);
      }
      this.resolve('Stream aborted.');
    };
    this.signal.onabort = this.abortHandler;
  }
  async disconnect(abort = false) {
    if (abort) {
      this.audioReadableAbortable.abort();
    }
    this.msd.disconnect();
    this.osc.disconnect();
    this.outputSource.disconnect();
    this.track.stop();
    try {
      await this.audioWriter.close();
      await this.audioWriter.closed;
      await this.inputReader.cancel();
    } catch (err) {
      throw err;
    }
    this.generator.stop();
    if (this.recorder && this.recorder.state === 'recording') {
      this.recorder.stop();
    }
    return this.ac.close();
  }
  async start() {
    return this.nativeTransferableStream();
  }
  async abort() {
    this.abortable.abort();
    if (this.source) {
      this.source.postMessage('Abort.', '*');
    }
    return this.promise;
  }
  async nativeTransferableStream() {
    return new Promise((resolve) => {
      onmessage = (e) => {
        this.source = e.source;
        if (typeof e.data === 'string') {
          console.log(e.data);
          if (e.data === 'Ready.') {
            this.source.postMessage(this.stdin, '*', [this.stdin]);
          }
          if (e.data === 'Local server off.') {
            document.body.removeChild(this.transferableWindow);
            this.transferableWindow = onmessage = null;
          }
        }
        if (e.data instanceof ReadableStream) {
          this.stdout = e.data;
          resolve(this.audioStream());
        }
      };
      this.transferableWindow = document.createElement('iframe');
      this.transferableWindow.style.display = 'none';
      this.transferableWindow.name = location.href;
      this.transferableWindow.src = this.src;
      document.body.appendChild(this.transferableWindow);
    }).catch((err) => {
      throw err;
    });
  }
  async audioStream() {
    let channelData = [];
    try {
      await this.ac.resume();
      await this.audioWriter.ready;
      await Promise.allSettled([
        this.stdout.pipeTo(
          new WritableStream({
            write: async (value, c) => {
              let i = 0;
              if (!this.init) {
                this.init = true;
                i = 44;
              }
              for (; i < value.buffer.byteLength; i++, this.readOffset++) {
                if (channelData.length === this.channelDataLength) {
                  this.inputController.enqueue(
                    new Uint8Array(
                      channelData.splice(0, this.channelDataLength)
                    )
                  );
                }
                channelData.push(value[i]);
              }
            },
            abort(e) {
              console.error(e.message);
            },
            close: async () => {
              console.log('Done writing input stream.');
              if (channelData.length) {
                this.inputController.enqueue(new Uint8Array(channelData.splice(0, channelData.length)));
              }
              this.inputController.close();
              this.source.postMessage('Done writing input stream.', '*');
            },
          }),
          { signal: this.signal }
        ),
        this.audioReadable.pipeTo(
          new WritableStream({
            write: async ({ timestamp }) => {
              const { value, done } = await this.inputReader.read();
              if (done) {
                await this.inputReader.closed;
                try {
                  await this.disconnect();
                } catch (err) {
                  console.warn(err.message);
                }
                console.log(
                  `readOffset:${this.readOffset}, duration:${this.duration}, ac.currentTime:${this.ac.currentTime}`,
                  `generator.readyState:${this.generator.readyState}, audioWriter.desiredSize:${this.audioWriter.desiredSize}`
                );
                return await Promise.all([
                  new Promise((resolve) => (this.stream.oninactive = resolve)),
                  new Promise((resolve) => (this.ac.onstatechange = resolve)),
                ]);
              }              
              const frame = new AudioData({
                format: 's16',
                sampleRate: 22050,
                numberOfChannels: 1,
                numberOfFrames: value.length / 2,
                timestamp,
                data: value,
              });
              this.duration += (frame.duration / 10**6);
              if (this.recorder && this.recorder.state === 'inactive') {
                this.recorder.start();
              }
              await this.audioWriter.write(frame);
            },
            abort(e) {
              console.error(e.message);
            },
            close() {
              console.log('Done reading input stream.');
            },
          }),
          { signal: this.audioReadableSignal }
        ),
      ]);
      this.resolve(
        this.recorder
          ? this.data && (await this.data.arrayBuffer())
          : 'Done streaming.'
      );
      return this.promise;
    } catch (err) {
      console.error(err);
      throw err;
    }
  }
 }
--- a/chromium_extension/README.md
+++ b/chromium_extension/README.md
 <h5>Motivation</h5>
 Web Speech API does not support SSML input to the speech synthesis engine https://github.com/WICG/speech-api/issues/10, or the ability to capture the output of `speechSynthesis.speak()` as a`MedaiStreamTrack` or raw audio https://lists.w3.org/Archives/Public/public-speech-api/2017Jun/0000.html.
 See [Issue 1115640: [FUGU] NativeTransferableStream](https://bugs.chromium.org/p/chromium/issues/detail?id=1115640).
 <h5>Synopsis</h5>
 Native Messaging => eSpeak NG => PHP `passthru()` => `fetch()` => Transferable Streams => `MediaStreamTrack`.
 Use local `espeak-ng` with `-m` option set in the browser. 
 Output speech sythesis audio as a live `MediaStreamTrack`.
 Use [Native Messaging](https://developer.chrome.com/extensions/nativeMessaging), PHP `passthru()` to input text and [Speech Synthesis Markup Language](https://www.w3.org/TR/speech-synthesis11/) as STDIN to [`espeak-ng`](https://github.com/espeak-ng/espeak-ng), stream STDOUT in "real-time" as live `MediaStreamTrack`. 
 <h5>Install<h5>
 <h6>Dependencies</h6>
 eSpeak NG [Building eSpeak NG](https://github.com/espeak-ng/espeak-ng/blob/master/docs/building.md#building-espeak-ng).
 PHP is used for `passthru()`. Substitute server language of choice.
 ```
 git clone https://github.com/guest271314/native-messaging-espeak-ng.git
 cd native-messaging-espeak-ng/
 chmod +x local_server.sh index.php
 ```
 Navigate to `chrome://extensions`, set `Developer mode` to on, click `Load unpacked`, select downloaded git directory.
 Note the generated extension ID, substitute that value for `<id>` in `native_messaging_espeakng.json`, `AudioStream.js`, `index.php`; add the value to `"extensions"` array in `manifest.json`.
 Substitute full local path to `local_server.sh` for `/path/to` in `native_messaging_espeakng.json`.
 Copy `native_messaging_espeakng.json` to `NativeMessagingHosts` directory in Chromium or Chrome configuration folder, on Linux, i.e., `~/.config/chromium`; `~/.config/google-chrome-unstable`.
 `cp native_messaging_espeakng ~/.config/chromium/NativeMessagingHosts`
 Reload extension.
 <h5>Usage</h5>
 On origins listed in `"matches"` array in `"web_accessible_resources"` object in `manifest.json`, e.g., at `console`
 ```
 var text = `Test`;
 var stdin = `espeak-ng -m --stdout "${text}"`;
 var espeakng = new AudioStream({ stdin, recorder: true });
 // espeakng.mediaStream: MediaStream containing MediaStreamTrack source output of espeak-ng --stdout
 var ab = await espeakng.start();
 console.log(
  URL.createObjectURL(new Blob([ab], { type: 'audio/webm;codecs=opus' }))
 );
 ```
 Abort the request and audio output.
 ```
 await espeakng.abort()
 ```
 To turn local server on and off with user action pin and click the extension icon on Chromium or Chrome toolbar.
--- a/chromium_extension/background.js
+++ b/chromium_extension/background.js
 chrome.action.onClicked.addListener(() => 
  chrome.runtime.sendNativeMessage('native_messaging_espeakng'
  , {}, (nativeMessage) => console.log({nativeMessage}))
 );
--- a/chromium_extension/index.php
+++ b/chromium_extension/index.php
 <?php 
 if (isset($_POST["espeakng"])) {
    header('Vary: Origin');
    header("Access-Control-Allow-Origin: chrome-extension://<id>");
    header("Access-Control-Allow-Methods: POST");
    header("Content-Type: application/octet-stream");
    header("X-Powered-By:");
    echo passthru($_POST["espeakng"]);
    exit();
  }
--- a/chromium_extension/local_server.sh
+++ b/chromium_extension/local_server.sh
 #!/bin/bash
 # https://stackoverflow.com/a/24777120
 send_message() {
  message="$1"
  # Calculate the byte size of the string.
  # NOTE: This assumes that byte length is identical to the string length!
  # Do not use multibyte (unicode) characters, escape them instead, e.g.
  # message='"Some unicode character:\u1234"'
  messagelen=${#message}
  # Convert to an integer in native byte order.
  # If you see an error message in Chrome's stdout with
  # "Native Messaging host tried sending a message that is ... bytes long.",
  # then just swap the order, i.e. messagelen1 <-> messagelen4 and
  # messagelen2 <-> messagelen3
  messagelen1=$(( ($messagelen      ) & 0xFF ))               
  messagelen2=$(( ($messagelen >>  8) & 0xFF ))               
  messagelen3=$(( ($messagelen >> 16) & 0xFF ))               
  messagelen4=$(( ($messagelen >> 24) & 0xFF ))               
  # Print the message byte length followed by the actual message.
  printf "$(printf '\\x%x\\x%x\\x%x\\x%x' \
        $messagelen1 $messagelpen2 $messagelen3 $messagelen4)%s" "$message"
 }
 local_server() {
  if pgrep -f 'php -S localhost:8000' > /dev/null; then
    pkill -f 'php -S localhost:8000' & send_message '"Local server off."' 
  else
    php -S localhost:8000 & send_message '"Local server on."'
  fi
 }
 local_server
--- a/chromium_extension/manifest.json
+++ b/chromium_extension/manifest.json
 {
  "name": "Native Messaging espeak-ng",
  "description": "Native Messaging => eSpeak NG => PHP passthru() => fetch() => Transferable Streams => MediaStreamTrack",
  "version": "2.0",
  "manifest_version": 3,
  "permissions": ["nativeMessaging", "tabs"],
  "background": {
    "service_worker": "background.js"
  },
  "web_accessible_resources": [    {
      "resources": [ "nativeTransferableStream.html", "nativeTransferableStream.js" ],
      "matches": [ "https://github.com/*", "https://bugs.chromium.org/*" ],
      "extensions": [ ]
  }],
  "action": {},
  "author": "guest271314"
 }
--- a/chromium_extension/nativeTransferableStream.html
+++ b/chromium_extension/nativeTransferableStream.html
 <!DOCTYPE html>
 <html>
 <head>
  <script src="nativeTransferableStream.js"></script>
 </head>
  <body>
  </body>
 </html>
--- a/chromium_extension/nativeTransferableStream.js
+++ b/chromium_extension/nativeTransferableStream.js
 onload = async () => {
  chrome.runtime.sendNativeMessage(
    'native_messaging_espeakng',
    {},
    async (nativeMessage) => {
      parent.postMessage(nativeMessage, name);
      await new Promise((resolve) => setTimeout(resolve, 100));
      const controller = new AbortController();
      const { signal } = controller;
      parent.postMessage('Ready.', name);
      onmessage = async (e) => {
        if (e.data instanceof ReadableStream) {
          try {
            const { value: file, done } = await e.data.getReader().read();
            const fd = new FormData();
            const stdin = await file.text();
            fd.append(file.name, stdin);
            const { body } = await fetch('http://localhost:8000', {
              method: 'post',
              cache: 'no-store',
              credentials: 'omit',
              body: fd,
              signal,
            });
            parent.postMessage(body, name, [body]);
          } catch (err) {
            parent.postMessage(err, name);
          }
        } else {
          if (e.data === 'Done writing input stream.') {
            chrome.runtime.sendNativeMessage(
              'native_messaging_espeakng',
              {},
              (nativeMessage) => {
                parent.postMessage(nativeMessage, name);
              }
            );
          }
          if (e.data === 'Abort.') {
            controller.abort();
          }
        }
      };
    }
  );
 };
--- a/chromium_extension/native_messaging_espeakng.json
+++ b/chromium_extension/native_messaging_espeakng.json
 {
  "name": "native_messaging_espeakng",
  "description": "Native Messaging => eSpeak NG => PHP passthru() => fetch() => Transferable Streams => MediaStreamTrack",
  "path": "/path/to/local_server.sh",
  "type": "stdio",
  "allowed_origins": [ "chrome-extension://<id>" ]
 }