Instruction: Describe the functionality and use cases of Flask's before_request and after_request decorators.
Context: This question tests the candidate's knowledge of Flask's request handling mechanism, specifically the customization of request preprocessing and postprocessing.
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Understanding before_request
The before_request decorator in Flask is used to execute a function before each request is processed. This is particularly useful for tasks that need to be done before any view function is called. For example, I've used before_request to implement custom authentication mechanisms, where I check if a user is authenticated before allowing them access to certain endpoints. Another common use case is to initialize or load resources that are needed for the request handling....