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流模板给出错误“jinja2.exceptions.UndefinedError:'stockStatus'未定义”

webhooks jinja2 flask python

Joeyohanlin · 技术社区 · 2 年前

我正在关注 tutorial 关于如何使用Python-Flask框架创建webhook。webhook旨在实现客户端(webhook生成器)和服务器(webhook-listener)之间的通信。服务器有一个文件,其中包含产品的库存单位和库存状态(“库存中”或“缺货”)。目标是允许客户端通过向服务器发送HTTPPOST请求来检索特定产品的库存状态。但是,我无法为webhook监听器加载页面( consumer.html )并接收到以下错误:

Traceback (most recent call last):
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\flask\app.py", line 2213, in __call__      
    return self.wsgi_app(environ, start_response)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\flask_socketio\__init__.py", line 43, in __call__
    return super(_SocketIOMiddleware, self).__call__(environ,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\engineio\middleware.py", line 74, in __call__
    return self.wsgi_app(environ, start_response)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\flask\app.py", line 2193, in wsgi_app      
    response = self.handle_exception(e)
               ^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\flask\app.py", line 2190, in wsgi_app      
    response = self.full_dispatch_request()
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\flask\app.py", line 1486, in full_dispatch_request
    rv = self.handle_user_exception(e)
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\flask\app.py", line 1484, in full_dispatch_request
    rv = self.dispatch_request()
         ^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\flask\app.py", line 1469, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\yuanl\Documents\GitHub\Gelato-API-webhooks\inventory\app_consumer.py", line 18, in index
    return render_template('consumer.html')
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\flask\templating.py", line 151, in render_template
    return _render(app, template, context)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\flask\templating.py", line 132, in _render 
    rv = template.render(context)
         ^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\jinja2\environment.py", line 1301, in render
    self.environment.handle_exception()
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\jinja2\environment.py", line 936, in handle_exception
    raise rewrite_traceback_stack(source=source)
  File "C:\Users\yuanl\Documents\GitHub\Gelato-API-webhooks\inventory\templates\consumer.html", line 16, in top-level template code
    {% for SKU, Stock_status in stockStatus.items() %}
  File "C:\Users\yuanl\AppData\Local\Programs\Python\Python311\Lib\site-packages\jinja2\environment.py", line 485, in getattr
    return getattr(obj, attribute)
           ^^^^^^^^^^^^^^^^^^^^^^^
jinja2.exceptions.UndefinedError: 'stockStatus' is undefined

的代码 consumer.html Jinja模板文件如下所示:

<!doctype html>
<html>
  <head>
    <title>Tasks Producer</title>
    <link href="../styles/style.css" rel="stylesheet">
    <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
  </head>
  <body class="container">
    <h1>Stock Sheet</h1>
    <table id="stockSheet">
      <tr>
        <th scope="col">SKU</th>
        <th scope="col">Stock Status</th>
      </tr>
    </table>
    {% for SKU, Stock_status in stockStatus.items() %}
        <script>
          var SKU = "{{SKU}}";
          var Stock_status = "{{Stock_status}}";
          document.getElementById("stockSheet").innerHTML += "<tr>" + "<td>"+ SKU + "</td>" + "<td>"+ Stock_status + "</td>" + "</tr>"
        </script>
    {% endfor %}
  </body>
</html>

该文件中的错误是 stockStatus 未定义。但是,变量是在 app_consumer.py 渲染和流式传输Jinja模板文件的文件,特别是 return Response(render_template_stream('consumer.html', stockStatus = tasks_consumer.sendStockStatus())) 陈述文件中的相关代码段如下所示:

from flask import Response, render_template, request
from flask_socketio import join_room
from init_consumer import app, socketio
import tasks_consumer
import uuid

# Render a template with a given context as a stream and return a TemplateStream
def render_template_stream(template_name, **context):
    app.update_template_context(context)
    t = app.jinja_env.get_template(template_name)
    rv = t.stream(context)
    rv.enable_buffering(5)
    return rv

# Render the assigned template file
@app.route("/", methods=['GET'])
def index():
    return render_template('consumer.html')

# Registers a function to be run before the first request to this instance of the application
# Create a unique session ID and store it within the application configuration file
@app.before_request
def initialize_params():
    if not hasattr(app.config,'uid'):
        sid = str(uuid.uuid4())
        app.config['uid'] = sid
        print("initialize_params - Session ID stored =", sid)

@app.route('/consumetasks', methods=['POST'])
def get_stock_status():
    print("Retrieving stock status")
    return Response(render_template_stream('consumer.html', stockStatus = tasks_consumer.sendStockStatus()))

的代码 tasks_consumer.py 定义 sendStockStatus() 功能如下所示:

import csv
from flask import request
from init_consumer import app, socketio
import json

# Receive the webhook requests and emit a SocketIO event back to the client
def send_message(data):
    status_code = 0
    if request.method == 'POST':
        roomid = app.config['uid']
        msg = json.dumps(data)
        event = "Send_stock_status"
        socketio.emit(event, msg, namespace = '/collectHooks', room = roomid)
        status_code = 200
    else:
        status_code = 405 # Method not allowed
    return status_code
    
# Retrieve the stock status of the products sent through the webhook requests and return them back to the client.   
def sendStockStatus():
    SKUlist = []
    stockSheet = {}
    with open("NZ_NVJ_Apparel_SKUs_sheet.csv", newline='') as csvFile:
        stockReader = csv.reader(csvFile, delimiter=',', quotechar='"')
        for row in stockReader:
            SKUlist.append(row[0])
    if request.method == 'POST':
        stockInfo = request.json
        stockStr = str(stockInfo)
        stockStr = stockStr.replace("\'", "\"")
        stockDict = json.loads(stockStr)
        for stock in stockDict["SKU"]:
            if stock in SKUlist:
                stockSheet.update({str(stock):"In Stock"})
            else:
                stockSheet.update({str(stock):"Out of Stock"})
    send_message(stockSheet)
    return stockSheet

我不明白是什么导致了这个错误。我在Jinja模板文件中使用了与 Jinja documentation 以及在 库存状态 由返回的词典 sendStockStatus() 中的函数 tasks_consumer.py 文件有人能给我指正确的方向吗?

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