Add well-known endpoint for Quay

Fixes #1790

endpoints/wellknown.py

@@ -0,0 +1,31 @@
+import json
+import logging
+
+from app import get_app_url
+from flask import Blueprint, make_response
+
+logger = logging.getLogger(__name__)
+wellknown = Blueprint('wellknown', __name__)
+
+@wellknown.route('/app-capabilities', methods=['GET'])
+def app_capabilities():
+  view_image_tmpl = '%s/{namespace}/{reponame}:{tag}' % get_app_url()
+  image_security_tmpl = ('%s/api/v1/repository/{namespace}/{reponame}/image/{imageid}/security' %
+                         get_app_url())
+
+  metadata = {
+    'appName': 'io.quay',
+    'capabilities': {
+      'io.quay.view-image': {
+        'url-template': view_image_tmpl,
+      },
+
+      'io.quay.image-security': {
+        'rest-api-template': image_security_tmpl,
+      },
+    },
+  }
+
+  resp = make_response(json.dumps(metadata))
+  resp.headers['Content-Type'] = 'application/json'
+  return resp