2016-04-23 56 views
2

我正在創建將處理數據的Web應用程序,所以我在Flask中使用了Server Sent Event。會話對象在Flask中不起作用stream_with_context函數

我需要將會話變量存儲在SSE函數中,但燒瓶不會在函數外面看到它。我能以某種方式修復它嗎?

MWE:

server.py:

from flask import Flask, render_template, session, Response, stream_with_context 
import time 

app = Flask(__name__) 
app.secret_key = b'132d2dcf59f9604c0b48e4e3a1a1cd19a0abf121b48a4777' 

@app.route('/') 
def get_page(): 
    return render_template('progress.html') 

@app.route('/progress') 
def progress(): 
    def generate(): 
     x = 0 
     while x < 100: 
      x = x + 10 
      print(x) 
      time.sleep(0.2) 
      yield "data:" + str(x) + "\n\n" 
     session['result'] = x 
     print(session['result']) #100 
    return Response(stream_with_context(generate()), mimetype= 'text/event-stream') 

@app.route('/done') 
def done(): 
    print(session['result']) #KeyError: 'result' 
    return session['result'] 

if __name__ == '__main__': 
    app.run(debug=True) 

progress.html:

<!DOCTYPE html> 
<html> 
<head> 
    <script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css"> 
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script> 
    <script> 

    var source = new EventSource("/progress"); 
    source.onmessage = function(event) { 
     $('.progress-bar').css('width', event.data+'%').attr('aria-valuenow', event.data); 
     if (event.data >=100) { 
      source.close(); 
      window.location = "http://127.0.0.1:5000/done" 
     } 
    } 
    </script> 
</head> 
<body> 
    <div class="progress" style="width: 50%; margin: 50px;"> 
     <div class="progress-bar progress-bar-striped active" role="progressbar" aria-valuenow="0" aria-valuemin="0" aria-valuemax="100" style="width: 0%"> 
    </div> 
</div> 
</body> 
</html> 

回答

1

會話是一個cookie。 Cookie以標題形式發送。在流的其餘部分發送之前,首先在響應中發送標題。開始響應後您無法修改會話。將所需的任何數據發送到流中,然後在接收端處理。

+0

好的,謝謝,我現在明白這一點。我應該將結果'x'傳遞給JS,並將此結果作爲url參數重定向到'/ done?result = x'並將其存儲在會話中的'done()'函數中?或者有更好的方法來做到這一點? – sweetSTEAM