serialize_http_request.py

import requests

req = requests.Request('POST', 'http://stackoverflow.com' , headers={'X-Custom': 'Test'}, data={
    'a': 1,
    'b': 2,
})

# TODO допилить напильником
# GET /wiki/HTTP HTTP/1.0
# Host: ru.wikipedia.org

REQUEST_TMPL = """{req.method} {req.url}
{headers_str}


{req.body}"""


def serialize_http_request(request):
    """
    At this point it is completely built and ready
    to be fired; it is "prepared".

    However pay attention at the formatting used in 
    this function because it is programmed to be pretty 
    printed and may differ from the actual request.
    """
    prepared_request = request.prepare()
    headers_str = '\n'.join('{}: {}'.format(k, v) for k, v in req.headers.items())
    return REQUEST_TMPL.format(req=prepared_request, headers_str=headers_str)

print(serialize_http_request(req))