Adding refresh_token_request hook

Author: violuke

requests_oauthlib/oauth2_session.py

@@ -95,6 +95,7 @@ def __init__(
             "access_token_response": set(),
             "refresh_token_response": set(),
             "protected_request": set(),
+            "refresh_token_request": set(),
         }
 
     def new_state(self):
@@ -429,6 +430,10 @@ def refresh_token(
                 "Content-Type": ("application/x-www-form-urlencoded;charset=UTF-8"),
             }
 
+        for hook in self.compliance_hook["refresh_token_request"]:
+            log.debug("Invoking refresh_token_request hook %s.", hook)
+            token_url, headers, body = hook(token_url, headers, body)
+
         r = self.post(
             token_url,
             data=dict(urldecode(body)),
@@ -529,6 +534,7 @@ def register_compliance_hook(self, hook_type, hook):
             access_token_response invoked before token parsing.
             refresh_token_response invoked before refresh token parsing.
             protected_request invoked before making a request.
+            refresh_token_request invoked before making a refresh request.
 
         If you find a new hook is needed please send a GitHub PR request
         or open an issue.