Debugging Empty Responses from HTTP Requests in Python

It can be frustrating when making an HTTP request in Python using the popular requests library and receiving a 200 OK status code, but the response body is empty. This article covers some common reasons you may encounter this, along with troubleshooting tips.

The key things to check are:

Verify Expected Response Body Format

Make sure the API or endpoint you are calling is actually supposed to return a non-empty JSON or text response body. Refer to the documentation for what format the responses should be in.

Check for Content Encoding

The response may have a content encoding set, such as gzip or deflate, but you are not properly decompressing it in your code. Check the Content-Encoding header in the response and handle this accordingly.

Decode the Response Bytes

Even if there is no content encoding, you may need to explicitly decode the response bytes to a string:

response.content.decode('utf-8')

Log Full Response Details

Enable full debug logging on your requests calls to output all response headers and data. This can uncover issues not visible when only checking the response body.

Test in Postman

Try making the same request in Postman to isolate whether the issue is in your Python code or with the API itself. Compare headers and response details.

Carefully going through these steps can uncover what is leading to empty response bodies. Often it ends up being something simple like needing to handle encoding or format the raw response bytes. Pay close attention to status codes, headers, and logging to narrow down where things may be going wrong.