Python 3.x 如何解决这个问题；TypeError:read（）缺少1个必需的位置参数：'；自我'&引用；

我正在使用Flask创建一个RESTAPI，以获取存储在MSSQL数据库中的所有书籍。当我在控制台中运行这段代码并打印数据时，它工作得很好。但当我作为Flask API运行并尝试在postman中获取所有数据时，它显示了以下错误：

完全追溯：

Traceback (most recent call last):
     File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 2309, in __call__
        return self.wsgi_app(environ, start_response)
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 2295, in wsgi_app
        response = self.handle_exception(e)
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 1741, in handle_exception
        reraise(exc_type, exc_value, tb)
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\_compat.py", line 35, in reraise
        raise value
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 2292, in wsgi_app
        response = self.full_dispatch_request()
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 1815, in full_dispatch_request
        rv = self.handle_user_exception(e)
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 1718, in handle_user_exception
        reraise(exc_type, exc_value, tb)
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\_compat.py", line 35, in reraise
        raise value
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 1813, in full_dispatch_request
        rv = self.dispatch_request()
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 1799, in dispatch_request
        return self.view_functions[rule.endpoint](**req.view_args)
    TypeError: read() missing 1 required positional argument: 'self'
    127.0.0.1 - - [13/Feb/2019 17:38:21] "GET / HTTP/1.1" 500 -
    Traceback (most recent call last):
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 2309, in __call__
        return self.wsgi_app(environ, start_response)
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 2295, in wsgi_app
        response = self.handle_exception(e)
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 1741, in handle_exception
        reraise(exc_type, exc_value, tb)
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\_compat.py", line 35, in reraise
        raise value
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 2292, in wsgi_app
        response = self.full_dispatch_request()
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 1815, in full_dispatch_request
        rv = self.handle_user_exception(e)
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 1718, in handle_user_exception
        reraise(exc_type, exc_value, tb)
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\_compat.py", line 35, in reraise
        raise value
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 1813, in full_dispatch_request
        rv = self.dispatch_request()
      File "C:\Users\raj.pandey\Desktop\Flask_API\lib\site-packages\flask\app.py", line 1799, in dispatch_request
        return self.view_functions[rule.endpoint](**req.view_args)
    TypeError: home() missing 1 required positional argument: 'self'

以下是我遇到错误的代码：

class MssqlConnection:
    def __init__(self):
        credentials = Credentials()
        self.driver = credentials.driver
        self.host = credentials.host
        self.database = credentials.database
        self.table = credentials.table
        self.user = credentials.user
        self.password = credentials.password

    @app.route('/books')
    def read(self):
        query = "Select id, name, price, isbn from dbo." + self.table
        cursor.execute(query)
        for row in cursor:
            data = {
                'id': row.id,
                'name': row.name,
                'price': row.price,
                'isbn': row.isbn
            }
            # print(data)
            return jsonify(data)

---

我已经检查过了，但仍然无法理解问题所在。

您的端点函数可能不在（甚至不应该）类中。只需从

def read（self）：

行中删除

self

参数，就可以了。在类作用域中编写代码时，应该使用“self”作为参数。您不在类范围内。因此，解决方案是

def read（）：

在Flask中，仅当您在url中放入一个参数，如

app.route（'/books/'）

时，才应将

somevariable

作为参数传递给端点函数，并写入

def myfunction（somevariable）：

您可以阅读以下文档：

---

您能添加完整的回溯吗？是的，当然，请稍等片刻为什么要将“self”参数传递给

def read（）

？这与

home（）

…self.table相同。在初始化后的类中，每个def都会获得self。没有它，我就无法访问“self.variable”，先生，你能把你的邮件id发给我吗？因为我不能在这里放那么多代码？因此，我将向您发送我的代码。通过从

read（）

方法中删除

self

，类变量

表

将不再可访问。Joey sir是对的，def read位于类作用域中，我没有在这里放置完整的代码，因为它非常长。但是flask认为“self”是url中的一个变量。您可以使用全局变量或创建服务对象，并从中获取数据。