use common base class for OAuth1.0 based API interfaces

gallery_dl/extractor/flickr.py

@@ -243,7 +243,7 @@ class FlickrSearchExtractor(FlickrExtractor):
         return self.api.photos_search(self.search)
 
 
-class FlickrAPI():
+class FlickrAPI(oauth.OAuth1API):
     """Minimal interface for the flickr API"""
     API_URL = "https://api.flickr.com/services/rest/"
     API_KEY = "ac4fd7aa98585b9eee1ba761c209de68"
@@ -264,20 +264,7 @@ class FlickrAPI():
     ]
 
     def __init__(self, extractor):
-        api_key = extractor.config("api-key", self.API_KEY)
-        api_secret = extractor.config("api-secret", self.API_SECRET)
-        token = extractor.config("access-token")
-        token_secret = extractor.config("access-token-secret")
-
-        if api_key and api_secret and token and token_secret:
-            self.session = oauth.OAuth1Session(
-                api_key, api_secret,
-                token, token_secret,
-            )
-            self.api_key = None
-        else:
-            self.session = extractor.session
-            self.api_key = api_key
+        oauth.OAuth1API.__init__(self, extractor)
 
         self.maxsize = extractor.config("size-max")
         if isinstance(self.maxsize, str):