From 1e591bfc62e3f1afdc2a10d198208363bf666766 Mon Sep 17 00:00:00 2001
From: Armen Zambrano Gasparnian <armenzg@mozilla.com>
Date: Thu, 4 Jun 2015 12:39:07 -0400
Subject: [PATCH] Verify last modification dates

---
 mozci/utils/transfer.py | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/mozci/utils/transfer.py b/mozci/utils/transfer.py
index 3e2b3e3..cf009da 100644
--- a/mozci/utils/transfer.py
+++ b/mozci/utils/transfer.py
@@ -1,3 +1,4 @@
+import calendar
 import gzip
 import json
 import logging
@@ -24,6 +25,24 @@ def path_to_file(filename):
     return filepath
 
 
+def _verify_last_mod(remote_last_mod_date, filename):
+    # Create a struct_time based on the server's last modified
+    datetime_struct = time.strptime(
+            remote_last_mod_date,
+            "%a, %d %b %Y %H:%M:%S %Z"
+    )
+    # Convert the struct_time to a local timestamp (instead of GMT timezone)
+    local_timestamp = calendar.timegm(datetime_struct)
+    # Set the creation and modified of the file
+    os.utime(filename, (local_timestamp, local_timestamp))
+    statinfo = os.stat(filename)
+    last_mod_date = time.strftime('%a, %d %b %Y %H:%M:%S GMT', time.gmtime(statinfo.st_mtime))
+
+    assert remote_last_mod_date == last_mod_date, \
+            "The modified time of the file (%s) should match the one of the server (%s)." % \
+            (last_mod_date, remote_last_mod_date)
+
+
 def _fetch_and_load_file(req, filename):
     """
     Helper private function to simply download a file, to show its progress and to verify
@@ -88,6 +107,8 @@ def _fetch_and_load_file(req, filename):
             with open(filename, 'wb') as fd:
                 json.dump(json_content, fd)
 
+        _verify_last_mod(req.headers['last-modified'], filename)
+
     return json_content
 
 
@@ -131,7 +152,9 @@ def load_file(filename, url):
 
         if req.status_code == 200:
             # The file on the server is newer
-            LOG.debug("The local file was last modified in %s. We need to delete the file and fetch it again." % last_mod_date)
+            LOG.info("The local file was last modified in %s. " % last_mod_date)
+            LOG.info("The server's last modified in %s" % req.headers['last-modified'])
+            LOG.debug("We need to delete the local file and fetch it again.")
             os.remove(filepath)
             return _fetch_and_load_file(req, filepath)
         elif req.status_code == 304: