Merge pull request #547 from looi/client_credentials_refresh

Auto refresh token for detected client_credentials grant type

authlib/oauth2/client.py

@@ -193,6 +193,10 @@ def fetch_token(self, url=None, body='', method='POST', headers=None,
         if grant_type is None:
             grant_type = self.metadata.get('grant_type')
 
+        if grant_type is None:
+            grant_type = _guess_grant_type(kwargs)
+            self.metadata['grant_type'] = grant_type
+
         body = self._prepare_token_endpoint_body(body, grant_type, **kwargs)
 
         if auth is None:
@@ -401,9 +405,6 @@ def _handle_token_hint(self, hook, url, token=None, token_type_hint=None,
             url, body, auth=auth, headers=headers, **session_kwargs)
 
     def _prepare_token_endpoint_body(self, body, grant_type, **kwargs):
-        if grant_type is None:
-            grant_type = _guess_grant_type(kwargs)
-
         if grant_type == 'authorization_code':
             if 'redirect_uri' not in kwargs:
                 kwargs['redirect_uri'] = self.redirect_uri