Add pagination support to tag history API

Fixes #198

endpoints/api/tag.py

@@ -16,12 +16,13 @@ from datetime import datetime
 @resource('/v1/repository/<repopath:repository>/tag/')
 @path_param('repository', 'The full path of the repository. e.g. namespace/name')
 class ListRepositoryTags(RepositoryParamResource):
-  """ Resource for listing repository tags. """
+  """ Resource for listing full repository tag history, alive *and dead*. """
 
   @require_repo_write
   @parse_args
   @query_param('specificTag', 'Filters the tags to the specific tag.', type=str, default='')
-  @query_param('limit', 'Limit to the number of results to return. Max 100.', type=int, default=50)
+  @query_param('limit', 'Limit to the number of results to return per page. Max 100.', type=int, default=50)
+  @query_param('page', 'Page index for the results. Default 1.', type=int, default=1)
   @nickname('listRepoTags')
   def get(self, args, namespace, repository):
     repo = model.get_repository(namespace, repository)
@@ -44,9 +45,21 @@ class ListRepositoryTags(RepositoryParamResource):
       return tag_info
 
     specific_tag = args.get('specificTag') or None
+
+    page = min(1, args.get('start', 1))
     limit = min(100, max(1, args.get('limit', 50)))
-    tags = model.list_repository_tag_history(repo, limit=limit, specific_tag=specific_tag)
-    return {'tags': [tag_view(tag) for tag in tags]}
+
+    # Note: We ask for limit+1 here, so we can check to see if there are
+    # additional pages of results.
+    tags = model.list_repository_tag_history(repo, page=page, size=limit+1,
+                                             specific_tag=specific_tag)
+
+    tags = list(tags)
+    return {
+      'tags': [tag_view(tag) for tag in tags[0:limit]],
+      'page': page,
+      'has_additional': len(tags) >= limit
+    }
 
 
 @resource('/v1/repository/<repopath:repository>/tag/<tag>')