Handle both old and new field names for versions

This needs to be in place before doing edgi-govdata-archiving/web-monitoring-db#776. This doesn't update the fields we *send*. The DB will initially be backwards compatible with the current import format, so we can ship this first, *then* upgrade the DB without anything breaking.

web_monitoring/cli/cli.py

@@ -560,7 +560,7 @@ def _load_known_versions(client, start_date, end_date):
                                    chunk_size=1000)
     # Limit to latest 500,000 results for sanity/time/memory
     limited_versions = islice(versions, 500_000)
-    cache = set(_version_cache_key(v["capture_time"], v["capture_url"])
+    cache = set(_version_cache_key(v["capture_time"], v.get("url", v.get("capture_url")))
                 for v in limited_versions)
     logger.debug(f'  Found {len(cache)} known versions')
     return cache

web_monitoring/db.py

@@ -1033,9 +1033,11 @@ def get_version_content(self, version_id):
         content : bytes
         """
         db_result = self.get_version(version_id)
-        content_uri = db_result['data']['uri']
+        # TODO: remove fallback once API migration is done:
+        # https://github.com/edgi-govdata-archiving/web-monitoring-db/issues/776
+        content_url = db_result['data'].get('body_url', db_result['data'].get('uri'))
         # override the session-level "accept: json" header
-        response = self.request(GET, content_uri, headers={'accept': None})
+        response = self.request(GET, content_url, headers={'accept': None})
         if response.headers.get('Content-Type', '').startswith('text/'):
             return response.text
         else: