[Solved] Which of the following is the correct way to define a custom middleware class in Flask? — Ans: class MyMiddleware: def __init__(self, app): self.app = app def __call__(self,... | Flask

Flask - Middleware and Extensions

Which of the following is the correct way to define a custom middleware class in Flask?

Aclass MyMiddleware: def __init__(self, app): self.app = app def __call__(self, environ, start_response): return self.app(environ, start_response)

Bdef MyMiddleware(app): return app

Cclass MyMiddleware: def handle_request(self): pass

Dclass MyMiddleware: def __init__(self): pass

Step-by-Step Solution

Solution:

Step 1: Check middleware class structure
Middleware must accept the app in __init__ and implement __call__ with environ and start_response.
Step 2: Validate options
Only class MyMiddleware: def __init__(self, app): self.app = app def __call__(self, environ, start_response): return self.app(environ, start_response) matches this pattern correctly. Others miss __call__ or parameters.
Final Answer:
Correct middleware class with __init__ and __call__ methods -> Option A
Quick Check:
Middleware class needs __call__ method [OK]

Quick Trick: Middleware class must implement __call__(environ, start_response) [OK]

Common Mistakes:

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Which of the following is the correct way to define a custom middleware class in Flask?