urllib3.response.HTTPResponse.headers is a dict, but vcr.stubs.VCRHTTPResponse.headers is not

[johnjameswhitman]

Problem

I'm dealing with some pydantic models that are deserializing a urrlib3.response.HTTPResponse, and they expect the headers attribute to be a dict. It looks like urllib3 deserializes headers into an HTTPHeaderDict that inherits from dict in the HTTPResponse constructor here:
https://github.com/urllib3/urllib3/blob/b07a669bd970d69847801148286b726f0570b625/src/urllib3/response.py#L327-L330

When I run a test w/ vcr, I'm getting a validation error about the headers not being a dict. After firing up a debugger, it seems like vcr.stubs.VCRHTTPResponse instead sets them to a http.client.HTTPMessage here:

vcrpy/vcr/stubs/__init__.py

Line 82 in f3147f5

self.headers = self.msg = parse_headers(headers)

Solution

Would it be possible to subclass, patch or otherwise modify how vcr handles response headers for urllib3? It looks like something similar might've been done for tornado, but I'm not super familiar with the available hooks:

vcrpy/vcr/stubs/tornado_stubs.py

Lines 53 to 62 in f3147f5

	response = HTTPResponse(
	request,
	code=vcr_response["status"]["code"],
	reason=vcr_response["status"]["message"],
	headers=headers,
	buffer=BytesIO(vcr_response["body"]["string"]),
	effective_url=vcr_response.get("url"),
	request_time=self.io_loop.time() - request.start_time,
	)
	return callback(response)