Instruction: Detail the steps from when a request is received by a Flask application to when a response is returned.
Context: This question tests the candidate's understanding of the Flask framework's inner workings and the lifecycle of an HTTP request within a Flask application.
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First, the journey begins when a client, which could be a web browser or any client-side application, sends a request to a Flask application. This request hits the web server, which, in the context of Flask, is typically Werkzeug, although Flask can work with other WSGI-compatible servers as well. This is where the initial parsing of the request URL occurs to determine the destination within the application.
Upon reaching the Flask application, the URL routing system takes the lead. Flask examines the request URL against the URL rules that have been defined with the @app.route decorators or through the application's URL map. This step is crucial as it determines which view function should handle the request based on the URL and optionally, the HTTP method (GET, POST, etc.)....
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