[Solved] Identify the issue in this middleware snippet:class FaultyMiddleware: def __init__(self, app): self.app = app def __call__(self, environ, start_response): response = self.... | Flask

Flask - Middleware and Extensions

Identify the issue in this middleware snippet:

class FaultyMiddleware:
    def __init__(self, app):
        self.app = app
    def __call__(self, environ, start_response):
        response = self.app(environ)
        return response

app.wsgi_app = FaultyMiddleware(app.wsgi_app)

AThe wrapped app is called without start_response argument

BThe __call__ method should not return anything

CThe __init__ method is missing required parameters

DMiddleware should not wrap app.wsgi_app

Step-by-Step Solution

Solution:

Step 1: Check __call__ Signature
WSGI app call requires both environ and start_response.
Step 2: Identify Error
Here, self.app(environ) misses start_response, causing a TypeError.
Final Answer:
The wrapped app is called without start_response argument -> Option A
Quick Check:
WSGI call must include start_response [OK]

Quick Trick: Always pass start_response to wrapped app call [OK]

Common Mistakes:

MISTAKES

Omitting start_response argument
Returning None instead of response iterable
Misunderstanding WSGI call signature

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More Flask Quizzes

Identify the issue in this middleware snippet:

Step 1: Check call Signature

Step 2: Identify Error

Final Answer:

Quick Check:

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Identify the issue in this middleware snippet:

Step 1: Check __call__ Signature

Step 2: Identify Error

Final Answer:

Quick Check:

Want More Practice?

Step 1: Check call Signature