tracker_service: send a Last-Modified header for /tracker/data/json

1 files changed, 8 insertions, 7 deletions

diff --git a/bin/tracker_service.py b/bin/tracker_service.py
index 8757d0c4da..7e89c65632 100755
--- a/bin/tracker_service.py
+++ b/bin/tracker_service.py
@@ -1298,7 +1298,7 @@ Debian bug number.'''),
            self.json_generation_interval seconds ago """
 
         if self.json_timestamp: # we've generated the JSON at least once
-            delta = datetime.now() - self.json_timestamp
+            delta = datetime.utcnow() - self.json_timestamp
             if delta.total_seconds() <= self.json_generation_interval:
                 # not expired yet, serve the cached data
                 return self.json_data
@@ -1450,15 +1450,16 @@ Debian bug number.'''),
 
         # store the JSON dump in memory, and update the generation
         # timestamp before returning
-        self.json_data = json.dumps(data, separators=(',', ':'))
-        self.json_timestamp = datetime.now()
+        new_data = json.dumps(data, separators=(',', ':'))
+        if new_data != self.json_data:
+            self.json_data = new_data
+            self.json_timestamp = datetime.utcnow()
         return self.json_data
 
     def page_json(self, path, params, url):
-        # FIXME: we want to send along a Last-Modified header, whose
-        # value will be:
-        #   self.json_timestamp.strftime("%a, %d %b %Y %H:%M:%S ") + TZ
-        return BinaryResult(self._get_json(),'application/octet-stream')
+        result = BinaryResult(self._get_json(),'application/octet-stream')
+        result.headers['Last-Modified'] = self.json_timestamp.strftime("%a, %d %b %Y %H:%M:%S GMT")
+        return result
 
     def page_debsecan(self, path, params, url):
         obj = '/'.join(path)