Issue 2234 - Add a WSGI controller to collect email addresses for the Adblock Browser iOS launch

sitescripts/formsubscribe/web/formsubscribe.py

+# coding: utf-8
+
+# This file is part of the Adblock Plus web scripts,
+# 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.
+#
+# Adblock Plus is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+
+import codecs
+import fcntl
+
+from sitescripts.utils import get_config
+from sitescripts.web import url_handler, form_handler
+
+@url_handler('/formsubscribe')

[Sebastian Noack, 2015/04/05 17:07:01]

Well, double-/single-quotes are currently quite mixed through our Python code.
The only rule we have so far is to stick to one of them consistently in the same
file.

+@form_handler
+def handleRequest(environ, start_response, data):
+  email = data.get('email', '').strip()
+  if not email:
+    start_response('400 Bad Request', [('Content-Type', 'text/plain')])
+    return ['No email address given.']
+
+  filename = get_config().get('formsubscribe', 'file')
+  with codecs.open(filename, 'a', 'utf-8', buffering=0) as file:

[Sebastian Noack, 2015/04/06 09:53:17]

In fact there are attempts to deprecate codecs.open for the past 5 years:
https://bugs.python.org/issue8796

+    fcntl.lockf(file, fcntl.LOCK_EX)

[kzar, 2015/04/05 15:45:14]

How does this work if the file is already locked? Is it blocking, just delaying
the new write slightly or would an exception be raised?

+    try:
+      print >>file, email
+    finally:
+      fcntl.lockf(file, fcntl.LOCK_UN)
+
+  start_response('200 OK', [('Content-Type', 'text/plain')])
+  return ["Thanks for your submission! We'll notify you before the launch."]