post_process.redirect: Add hook to remove redirections

Signed-off-by: François Boulogne <fboulogne sciunto org>
Signed-off-by: W. Trevor King <wking@tremily.us>

diff --git a/rss2email/post_process/redirect.py b/rss2email/post_process/redirect.py
new file mode 100644 (file)
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+++ b/rss2email/post_process/redirect.py
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+# Copyright (C) 2013 Francois Boulogne <fboulogne at april dot org>
+#
+# This file is part of rss2email.
+#
+# rss2email is free software: you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation, either version 2 of the License, or (at your option) version 3 of
+# the License.
+#
+# rss2email 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
+# rss2email.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Remove redirects on the post URL.
+
+Several websites use redirects (e.g. feedburner) for various reasons like
+statistics. You may want to avoid this for privacy or for durability.
+
+This hook finds and uses the real url behind redirects.
+"""
+
+import urllib
+import re
+
+def process(feed, parsed, entry, guid, message):
+    # decode message
+    encoding = message.get_charsets()[0]
+    content = str(message.get_payload(decode=True), encoding)
+
+    # Get the link
+    link = entry['link']
+    if not link:
+        return message
+
+    # Remove the redirect and modify the content
+    try:
+        direct_link = urllib.request.urlopen(link).geturl()
+    except:
+        return message
+    content = re.sub(re.escape(link), direct_link, content, re.MULTILINE)
+
+    # clear CTE and set message. It can be important to clear the CTE
+    # before setting the payload, since the payload is only re-encoded
+    # if CTE is not already set.
+    del message['Content-Transfer-Encoding']
+    message.set_payload(content, charset=encoding)
+
+    return message