发送并发请求时的接口错误（0，''）

Question

我正在使用Flask和PyMySQL构建一个简单的应用程序，以便在学术上使用JMeter进行负载测试。它已经接收请求并发出响应。但是当我发送多个请求时，它会在几个请求（有时只有一个请求）之后显示以下错误。在

Traceback (most recent call last):
  File "/home/username/BossFight/python/venv/lib/python3.6/site-packages/flask/app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/username/BossFight/python/venv/lib/python3.6/site-packages/flask/app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/username/BossFight/python/venv/lib/python3.6/site-packages/flask/app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/username/BossFight/python/venv/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/home/username/BossFight/python/venv/lib/python3.6/site-packages/flask/app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/username/BossFight/python/venv/lib/python3.6/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/username/BossFight/python/helloflask.py", line 82, in get_driver
    if (authentication_success(token)):
  File "/home/username/BossFight/python/helloflask.py", line 21, in authentication_success
    cursor.execute("SELECT COUNT(*) AS matches FROM users WHERE id=%s", (id))
  File "/home/username/BossFight/python/venv/lib/python3.6/site-packages/pymysql/cursors.py", line 170, in execute
    result = self._query(query)
  File "/home/username/BossFight/python/venv/lib/python3.6/site-packages/pymysql/cursors.py", line 328, in _query
    conn.query(q)
  File "/home/username/BossFight/python/venv/lib/python3.6/site-packages/pymysql/connections.py", line 515, in query
    self._execute_command(COMMAND.COM_QUERY, sql)
  File "/home/username/BossFight/python/venv/lib/python3.6/site-packages/pymysql/connections.py", line 745, in _execute_command
    raise err.InterfaceError("(0, '')")
pymysql.err.InterfaceError: (0, '')

在那之后，它不再以http500响应，必须重新启动。在

以下是消息来源的相关部分：

^{pr2}$

请记住，我是Python的初学者。任何帮助都将不胜感激。在

Answer 1

问题可能是你有一个全球联系。在web应用程序中，每个请求都应该有自己的db连接。因此，get_driver函数应该创建一个连接，并在连接完成后关闭该连接（在finally子句中）。在

比如说：

def create_connection():
    return pymysql.connect(
        host='localhost',
        db='omnibus',
        user='starleaf1',
        password='alleluia',
        cursorclass=pymysql.cursors.DictCursor
    )

@app.route('/api/driver/<string:driver_id>', methods=['GET'])
def get_driver(driver_id):
    connection = create_connection()
    try:
        cursor = connection.cursor()
        token=request.headers['Authorization'][7:]
        if (authentication_success(token)):
            cursor.execute("SELECT COUNT(*) AS matches FROM users WHERE id=%s", (driver_id))
            driver=cursor.fetchone()
            if (not(driver is None)):
                return jsonify(message="ok",driver=driver)
            else:
                return jsonify(message="not found"),404
        else:
            return jsonify(message="authentication required"),401
    finally:
        connection.close()