Issue 3168 - Add a script for generating new content blocker lists

generate_lists.py

 #!/usr/bin/env python
 # coding: utf-8
 
 # This file is part of Adblock Plus <https://adblockplus.org/>,
 # Copyright (C) 2006-2015 Eyeo GmbH
 #
 # Adblock Plus is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
 # published by the Free Software Foundation.
 #
@@ skipping 23 matching lines @@
   if os.path.isdir(ABP2BLOCKLIST_PATH):
     subprocess.check_call(["hg", "pull", "-u", "-R", ABP2BLOCKLIST_PATH])
   else:
     subprocess.check_call(["hg", "clone", ABP2BLOCKLIST_URL,
                            ABP2BLOCKLIST_PATH])
   subprocess.check_call(["npm", "install"], cwd=ABP2BLOCKLIST_PATH)
 
 def _download_filter_lists():
   try:
     easylist_response = urllib2.urlopen(EASYLIST_URL)
-    easylist_file = tempfile.NamedTemporaryFile(mode="w+")
+    easylist_file = tempfile.NamedTemporaryFile(mode="wb+")
     shutil.copyfileobj(easylist_response, easylist_file)
   finally:
     easylist_response.close()

[Sebastian Noack, 2015/10/21 20:56:23]

Nit: An empty line after each finally block would improve the readability.

[Felix Dahlke, 2015/10/22 02:43:45]

Done.

+
   try:
     exceptionrules_response = urllib2.urlopen(EXCEPTIONRULES_URL)
-    exceptionrules_file = tempfile.NamedTemporaryFile(mode="w+")
+    exceptionrules_file = tempfile.NamedTemporaryFile(mode="wb+")
     shutil.copyfileobj(exceptionrules_response, exceptionrules_file)
   finally:
     exceptionrules_response.close()
+
   return (easylist_file, exceptionrules_file)
 
 def _convert_filter_list(source_file, destination_path):
   source_file.seek(0)
-  with open(destination_path, "w") as destination_file:
+  with open(destination_path, "wb") as destination_file:
     subprocess.check_call(["node", "abp2blocklist.js"],
                           cwd=ABP2BLOCKLIST_PATH, stdin=source_file,
                           stdout=destination_file)
 
 def _concatenate_files(*source_files):
-  destination_file = tempfile.NamedTemporaryFile(mode="w+")
+  destination_file = tempfile.NamedTemporaryFile(mode="wb+")
   for source_file in source_files:
     source_file.seek(0)
     shutil.copyfileobj(source_file, destination_file)
   return destination_file
 
 if __name__ == "__main__":
   print "Fetching/updating abp2blocklist ..."
   _update_abp2blocklist()
 
   print "Downloading filter lists ..."
   easylist_file, exceptionrules_file = _download_filter_lists()

[Sebastian Noack, 2015/10/21 21:14:35]

Mind closing the temporary files again?

[Felix Dahlke, 2015/10/22 02:43:45]

The OS is closing the files when the runtime terminates anyway, so I thought
that wasn't necessary. However, I've learned that the files aren't necessarily
flushed - that has to happen in the runtime, and while CPython seems to do it, I
guess not all do.

I'm closing them explicitly now, but I'm not really convinced, now it looks a
lot like the old variant where I was explicitly removing the temporary files
again. Anyway, I'm fine with this, I don't think it's worth more gold plating.

 
-  print "Generating %s ..." % os.path.basename(EASYLIST_CONTENT_BLOCKER_PATH)
-  _convert_filter_list(easylist_file, EASYLIST_CONTENT_BLOCKER_PATH)
+  try:
+    print "Generating %s ..." % os.path.basename(EASYLIST_CONTENT_BLOCKER_PATH)
+    _convert_filter_list(easylist_file, EASYLIST_CONTENT_BLOCKER_PATH)
 
-  print "Generating %s ..." % os.path.basename(COMBINED_CONTENT_BLOCKER_PATH)
-  combined_file = _concatenate_files(easylist_file, exceptionrules_file)
-  _convert_filter_list(combined_file, COMBINED_CONTENT_BLOCKER_PATH)
+    print "Generating %s ..." % os.path.basename(COMBINED_CONTENT_BLOCKER_PATH)
+    with _concatenate_files(easylist_file, exceptionrules_file) as combined_file:
+      _convert_filter_list(combined_file, COMBINED_CONTENT_BLOCKER_PATH)
+  finally:
+    easylist_file.close()
+    exceptionrules_file.close()