Crawler backend

sitescripts/crawler/bin/extract_crawler_sites.py

+# coding: utf-8
+
+# This Source Code is subject to the terms of the Mozilla Public License
+# version 2.0 (the "License"). You can obtain a copy of the License at
+# http://mozilla.org/MPL/2.0/.
+
+import os, re, subprocess
+from sitescripts.utils import get_config
+
+def hg(args):
+  return subprocess.Popen(["hg"] + args, stdout = subprocess.PIPE)
+
+def extract_urls(filter_list_dir):
+  os.chdir(filter_list_dir)
+  process = hg(["log", "--template", "{desc}\n"])
+  urls = set([])
+
+  while True:
+    line = process.stdout.readline()
+    if line == "":

[Wladimir Palant, 2012/09/14 17:24:18]

Is this really a good break condition? An empty commit line is unlikely but
possible... Anyway, how about "for line in process.stdout:" instead of a while
loop?

[Felix Dahlke, 2012/09/26 15:20:30]

Done. An empty commit line would be "\n", but you're definitely right that for
... in is nicer.

+      break
+
+    matches = re.match(r"[A-Z]:.*(https?://.*)", line)

[Wladimir Palant, 2012/09/14 17:24:18]

What if we have some additional text following the URL? Or an inexperienced
EasyList author deviates from the "A:" format? I would prefer something more
generic like r"\bhttps?://\S+", maybe even with an additional .strip(",.!?")
below.

[Felix Dahlke, 2012/09/26 15:20:30]

Done.

+    if not matches:
+      continue
+
+    url = matches.group(1).strip()
+    urls.add(url)
+
+  return urls
+
+def print_statements(urls):
+  for url in urls:
+    print "INSERT INTO crawler_sites (url) VALUES ('" + url + "');"

[Wladimir Palant, 2012/09/14 17:24:18]

While this might not be a big issue here, failing to escape values in SQL
statements is a bad habit. Please add escaping or - better - eliminate the SQL
file as intermediate step. Just add the URLs to the database immediately using
prepared statements.

[Felix Dahlke, 2012/09/26 15:20:30]

Done. I'd rather stick to generating a file with statements. More convenient to
test/verify, and we can keep old files for regression testing.

+
+if __name__ == "__main__":
+  filter_list_dir = get_config().get("crawler", "filter_list_repository")
+  urls = extract_urls(filter_list_dir)
+  print_statements(urls)