Setting HTTP User-Agent header with requests-oauthlib

Question

I'm using the requests-oauthlib library to get a request token from an OAuth (v1) provider.

oauth = OAuth1Session(CONSUMER_KEY, client_secret=CONSUMER_SECRET,
                      signature_method=SIGNATURE_HMAC,
                      signature_type=SIGNATURE_TYPE_AUTH_HEADER)

resp = oauth.fetch_request_token(url=REQUEST_TOKEN_URL)

I'd like to send a custom User-Agent header with the request token fetch request and include some contact information in case there are ever any problems with my script. Can this be done?

Answer 1

It's possible to pass in a client class to the OAuth1Session constructor. From the docblock in the relevant file:

"""
    :param client_class: A subclass of `oauthlib.oauth1.Client` to use with
                         `requests_oauthlib.OAuth1` instead of the default
"""

Within the oauthlib.oauth1.Client class, the _render(self, request, formencode=False, realm=None) method appears responsible for preparing the request. Since unrelated headers don't impact the base string that the request signature is created from, adding a new header/changing an existing User-Agent header shouldn't cause the signature to change in any way.

As such, we can create a custom client class, override the _render method and call the implementation in the parent class once we've added our header:

class CustomClient(Client):
    def _render(self, request, formencode=False, realm=None):
        request.headers['User-Agent'] = "FooClient/1.0"
        return super()._render(request, formencode, realm)

The code that instantiates OAuth1Session then simply needs to reference the above class:

oauth = OAuth1Session(CONSUMER_KEY, client_secret=CONSUMER_SECRET,
                          signature_method=SIGNATURE_HMAC,
                          signature_type=SIGNATURE_TYPE_AUTH_HEADER, client_class=CustomClient)