better combination of urls

Co-authored-by: Simone Orsi <[email protected]>

webservice/components/request_adapter.py

@@ -68,7 +68,7 @@ def _get_url(self, url=None, url_params=None, **kwargs):
             url = self.collection.url
         elif not url.startswith(self.collection.url):
             if not url.startswith("http"):
-                url = self.collection.url + url
+                url = f"{self.collection.url.rstrip('/')/{url.lstrip('/')"
             else:
                 # TODO: if url is given, we should validate the domain
                 # to avoid abusing a webservice backend for different calls.