“return render_template（）”不起作用[XMLHttpRequest（）&flask]

Question

我想认识到这一点

1. 用户与web浏览器对话
2. 网络浏览器（GoogleChrome）将用户的语音记录为WAV文件（Recorder.js），并将其发送到python服务器
3. Python服务器调用Google云文本到语音API并转录WAV文件
4. 将转录文本发送到web浏览器

我使用Windows 10、WSL、Debian 10/buster、python3.7.6和Google Chrome在本地开发了这个应用程序

我实现了步骤1、2、3，但没有实现步骤4。 在步骤2中，我使用XMLHttpRequest()将WAV文件发送到python flask服务器。 因此，在步骤4中，我不能以普通方式使用return render_template()

我搜索了“XMLHttpRequest（）flask return render_template（）”并找到了一个要使用的解决方案（How to get the response of XMLHttpRequest?）

当XMLHttpRequest.readyState等于XMLHttpRequest.DONE时XMLHttpRequest.responseText在XMLHttpRequest.onreadystatechange中

xhr.onreadystatechange = function() {
    if (xhr.readyState == XMLHttpRequest.DONE) {
        alert(xhr.responseText);
    }
}

因此，我将此代码添加到app.js中，但仍然无法获取return render_template()。这是终端的结果

127.0.0.1 - - [04/Feb/2020 16:55:58] "GET / HTTP/1.1" 200 -
['Transcript: 明日雪が降らないといいです。']
127.0.0.1 - - [04/Feb/2020 16:56:25] "POST / HTTP/1.1" 200 -

你能给我一些信息或建议吗？我知道有很多类似的问题；堆垛机溢出。我读了10多篇文章并尝试了它们，但我还没有解决我的困难。你能告诉我如何更改我的密码吗

先谢谢你

真的，卡祖

---

我的目录结构在这里

.
├── app.yaml
├── credentials.json
├── file.wav(uploaded WAV file)
├── main.py
├── Pipfile
├── Pipfile.lock
├── static
│   └── js
│       └── app.js
└── templates
    ├── index.html
    └── result.html

这是app.js

//webkitURL is deprecated but nevertheless
URL = window.URL || window.webkitURL;

var gumStream;                      //stream from getUserMedia()
var rec;                            //Recorder.js object
var input;                          //MediaStreamAudioSourceNode we'll be recording

// shim for AudioContext when it's not avb. 
var AudioContext = window.AudioContext || window.webkitAudioContext;
var audioContext //audio context to help us record

var recordButton = document.getElementById("recordButton");
var stopButton = document.getElementById("stopButton");
var pauseButton = document.getElementById("pauseButton");

//add events to those 2 buttons
recordButton.addEventListener("click", startRecording);
stopButton.addEventListener("click", stopRecording);
pauseButton.addEventListener("click", pauseRecording);

function startRecording() {
    console.log("recordButton clicked");

    /*
        Simple constraints object, for more advanced audio features see
        https://addpipe.com/blog/audio-constraints-getusermedia/
    */

    var constraints = { audio: true, video:false }

    /*
        Disable the record button until we get a success or fail from getUserMedia() 
    */

    recordButton.disabled = true;
    stopButton.disabled = false;
    pauseButton.disabled = false

    /*
        We're using the standard promise based getUserMedia() 
        https://developer.mozilla.org/en-US/docs/Web/API/MediaDevices/getUserMedia
    */

    navigator.mediaDevices.getUserMedia(constraints).then(function(stream) {
        console.log("getUserMedia() success, stream created, initializing Recorder.js ...");

        /*
            create an audio context after getUserMedia is called
            sampleRate might change after getUserMedia is called, like it does on macOS when recording through AirPods
            the sampleRate defaults to the one set in your OS for your playback device

        */
        audioContext = new AudioContext();

        //update the format 
        document.getElementById("formats").innerHTML="Format: 1 channel pcm @ "+audioContext.sampleRate/1000+"kHz"

        /*  assign to gumStream for later use  */
        gumStream = stream;

        /* use the stream */
        input = audioContext.createMediaStreamSource(stream);

        /* 
            Create the Recorder object and configure to record mono sound (1 channel)
            Recording 2 channels  will double the file size
        */
        rec = new Recorder(input,{numChannels:1})

        //start the recording process
        rec.record()

        console.log("Recording started");

    }).catch(function(err) {
        //enable the record button if getUserMedia() fails
        recordButton.disabled = false;
        stopButton.disabled = true;
        pauseButton.disabled = true
    });
}

function pauseRecording(){
    console.log("pauseButton clicked rec.recording=",rec.recording );
    if (rec.recording){
        //pause
        rec.stop();
        pauseButton.innerHTML="Resume";
    }else{
        //resume
        rec.record()
        pauseButton.innerHTML="Pause";

    }
}

function stopRecording() {
    console.log("stopButton clicked");

    //disable the stop button, enable the record too allow for new recordings
    stopButton.disabled = true;
    recordButton.disabled = false;
    pauseButton.disabled = true;

    //reset button just in case the recording is stopped while paused
    pauseButton.innerHTML="Pause";

    //tell the recorder to stop the recording
    rec.stop();

    //stop microphone access
    gumStream.getAudioTracks()[0].stop();

    //create the wav blob and pass it on to createDownloadLink
    rec.exportWAV(createDownloadLink);
}

function createDownloadLink(blob) {

    var url = URL.createObjectURL(blob);
    var au = document.createElement('audio');
    var li = document.createElement('li');
    var link = document.createElement('a');

    //name of .wav file to use during upload and download (without extendion)
    var filename = new Date().toISOString();

    //add controls to the <audio> element
    au.controls = true;
    au.src = url;

    //save to disk link
    link.href = url;
    link.download = filename+".wav"; //download forces the browser to donwload the file using the  filename
    link.innerHTML = "Save to disk";

    //add the new audio element to li
    li.appendChild(au);

    //add the filename to the li
    li.appendChild(document.createTextNode(filename+".wav "))

    //add the save to disk link to li
    li.appendChild(link);

    //upload link
    var upload = document.createElement('a');
    upload.href="#";
    upload.innerHTML = "Upload";
    upload.addEventListener("click", function(event){
          var xhr=new XMLHttpRequest();
          xhr.onreadystatechange = function() {
            if (xhr.readyState == XMLHttpRequest.DONE) {
                alert(xhr.responseText);
            }
        }
          var fd=new FormData();
          fd.append("audio_data",blob, filename);
          xhr.open("POST","/",true);
          xhr.send(fd);
    })
    li.appendChild(document.createTextNode (" "))//add a space in between
    li.appendChild(upload)//add the upload link to li

    //add the li element to the ol
    recordingsList.appendChild(li);
}

这是main.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
from flask import Flask
from flask import request
from flask import render_template
from flask import send_file
from google.cloud import speech
from google.cloud.speech import enums
from google.cloud.speech import types
import os
import io

app = Flask(__name__)

@app.route("/", methods=['POST', 'GET'])
def index():
    if request.method == "POST":
        f = open('./file.wav', 'wb')
        f.write(request.files['audio_data'].read())
        f.close()

        os.environ["GOOGLE_APPLICATION_CREDENTIALS"]="credentials.json"
        client = speech.SpeechClient()
        with io.open('./file.wav', 'rb') as audio_file:
            content = audio_file.read()

        audio = types.RecognitionAudio(content=content)
        config = types.RecognitionConfig(
            encoding=enums.RecognitionConfig.AudioEncoding.LINEAR16,
            language_code='ja-JP',
            enable_automatic_punctuation=True)
        response = client.recognize(config, audio)

        resultsentence = []
        for result in response.results:
            # The first alternative is the most likely one for this portion.
            sentence = u'Transcript: {}'.format(result.alternatives[0].transcript)
            resultsentence.append(sentence)

        print(resultsentence)

        return render_template("result.html", resultsentence=resultsentence)
    else:
        return render_template("index.html")

if __name__ == "__main__":
    app.run()

这是index.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>Simple Recorder.js demo with record, stop and pause - addpipe.com</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
  </head>
  <body>
    <h1>Simple Recorder.js demo</h1>

    <div id="controls">
     <button id="recordButton">Record</button>
     <button id="pauseButton" disabled>Pause</button>
     <button id="stopButton" disabled>Stop</button>
    </div>
    <div id="formats">Format: start recording to see sample rate</div>
    <p><strong>Recordings:</strong></p>
    <ol id="recordingsList"></ol>
    <!-- inserting these scripts at the end to be able to use all the elements in the DOM -->
    <script src="https://cdn.rawgit.com/mattdiamond/Recorderjs/08e7abd9/dist/recorder.js"></script>
    <script src="/static/js/app.js"></script>
  </body>
</html>

这是result.html

<!DOCTYPE html>
<html>
<body>
    {{ resultsentence }}
</body>
</html>

Answer 1

它的使用者是因为您正在调用一个路由，该路由在Ajax请求（XMLHttpRequest）中更改HTML，因此您有两个选项，第一个选项是更改HTML响应，如下所示：

xhr.onreadystatechange = function() {
    if (xhr.readyState == XMLHttpRequest.DONE) {
        document.write(xhr.responseText);
    }
}
// or using query(its better to me)

$.ajax({
        type: "POST",
        contentType: 'application/json',
        url: "/",
        data: {audio_data: blob}
        success:function(response){
            document.write(response); 
       }
    });

另一种方法是制作一个API，因此您不需要调用render_模板，您只需要在索引函数中返回ResultContent（此结果需要采用dict格式）

@app.route("/", methods=['POST', 'GET'])
def index():
    if request.method == "POST":
        #the image logic...

        return make_response(resultsentence)
    else:
        return render_template("index.html")

这样，您将需要使用javascript在前端处理响应