[Solved] Identify the error in this middleware code snippet: class BadMiddleware: def __init__(self, app): self.app = app def __call__(self, request): print('Middleware active') return self.app(request) | Flask

Flask - Middleware and Extensions

Identify the error in this middleware code snippet:

class BadMiddleware:
    def __init__(self, app):
        self.app = app
    def __call__(self, request):
        print('Middleware active')
        return self.app(request)

AMissing __init__ method to accept app

B__call__ method has wrong parameters; should be (environ, start_response)

CMiddleware class should not print anything

DThe return statement should be outside __call__

Step-by-Step Solution

Solution:

Step 1: Check __call__ method signature
WSGI middleware __call__ must accept (environ, start_response), not (request).
Step 2: Validate other parts
__init__ is correct, printing is allowed, return inside __call__ is correct.
Final Answer:
__call__ method has wrong parameters; should be (environ, start_response) -> Option B
Quick Check:
Middleware __call__ signature = (environ, start_response) [OK]

Quick Trick: Middleware __call__ needs environ and start_response params [OK]

Common Mistakes:

MISTAKES

Using Flask request object instead of WSGI params
Omitting start_response parameter
Misplacing return statement

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Identify the error in this middleware code snippet:

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Step 2: Validate other parts

Final Answer:

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Identify the error in this middleware code snippet:

Step 1: Check __call__ method signature

Step 2: Validate other parts

Final Answer:

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Step 1: Check call method signature