Why is my Flask request.json returning None, and how can I fix it?

Retrieving POSTed JSON in Flask

In Flask, accessing the content of a POST request in JSON format can be achieved using the request.json attribute. However, if you encounter None when trying to access the posted JSON, it's essential to understand the requirements for proper retrieval.

Firstly, the request content type must be set to application/json for the request.json property or the request.get_json() method to function correctly. If the content type is not set accordingly, these methods will return None. As stated in the Flask Request documentation:

"The parsed JSON data if mimetype indicates JSON (application/json, see .is_json)."

To circumvent this content type requirement, you can use the force=True argument when calling request.get_json(), which bypasses the check.

It's important to note that if an exception arises during JSON parsing, it indicates that the JSON data is invalid or malformed. In such cases, it's recommended to use a JSON validator to verify the data's integrity before proceeding.

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