add syndication extension

feedgen/ext/syndication.py

@@ -0,0 +1,60 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright 2015 Kenichi Sato <ksato9700@gmail.com>
+#
+
+'''
+Extends FeedGenerator to support Syndication module
+
+See below for details
+http://web.resource.org/rss/1.0/modules/syndication/
+'''
+
+from lxml import etree
+from feedgen.ext.base import BaseExtension
+
+SYNDICATION_NS = 'http://purl.org/rss/1.0/modules/syndication/'
+PERIOD_TYPE = ('hourly', 'daily', 'weekly', 'monthly', 'yearly')
+
+
+def _set_value(channel, name, value):
+    if value:
+        newelem = etree.SubElement(channel, '{%s}' % SYNDICATION_NS + name)
+        newelem.text = value
+
+
+class SyndicationExtension(BaseExtension):
+    def __init__(self):
+        self._update_period = None
+        self._update_freq = None
+        self._update_base = None
+
+    def extend_ns(self):
+        return {'sy': SYNDICATION_NS}
+
+    def extend_rss(self, rss_feed):
+        channel = rss_feed[0]
+        _set_value(channel, 'UpdatePeriod', self._update_period)
+        _set_value(channel, 'UpdateFrequency', str(self._update_freq))
+        _set_value(channel, 'UpdateBase', self._update_base)
+
+    def update_period(self, value):
+        if value not in PERIOD_TYPE:
+            raise ValueError('Invalid update period value')
+        self._update_period = value
+        return self._update_period
+
+    def update_frequency(self, value):
+        if type(value) is not int or value <= 0:
+            raise ValueError('Invalid update frequency value')
+        self._update_freq = value
+        return self._update_freq
+
+    def update_base(self, value):
+        # the value should be in W3CDTF format
+        self._update_base = value
+        return self._update_base
+
+
+class SyndicationEntryExtension(BaseExtension):
+    pass

feedgen/tests/test_extension.py

@@ -0,0 +1,50 @@
+# -*- coding: utf-8 -*-
+
+"""
+Tests for extensions
+"""
+
+import unittest
+from ..feed import FeedGenerator
+from lxml import etree
+
+
+class TestExtensionSyndication(unittest.TestCase):
+
+    def setUp(self):
+        self.fg = FeedGenerator()
+        self.fg.load_extension('syndication')
+        self.fg.title('title')
+        self.fg.link(href='http://example.com', rel='self')
+        self.fg.description('description')
+
+    def test_update_period(self):
+        for period_type in ('hourly', 'daily', 'weekly',
+                            'monthly', 'yearly'):
+            self.fg.syndication.update_period(period_type)
+            root = etree.fromstring(self.fg.rss_str())
+            a = root.xpath('/rss/channel/sy:UpdatePeriod',
+                           namespaces={
+                               'sy':'http://purl.org/rss/1.0/modules/syndication/'
+                           })
+            assert a[0].text == period_type
+
+    def test_update_frequency(self):
+        for frequency in (1, 100, 2000, 100000):
+            self.fg.syndication.update_frequency(frequency)
+            root = etree.fromstring(self.fg.rss_str())
+            a = root.xpath('/rss/channel/sy:UpdateFrequency',
+                           namespaces={
+                               'sy':'http://purl.org/rss/1.0/modules/syndication/'
+                           })
+            assert a[0].text == str(frequency)
+
+    def test_update_base(self):
+        base = '2000-01-01T12:00+00:00'
+        self.fg.syndication.update_base(base)
+        root = etree.fromstring(self.fg.rss_str())
+        a = root.xpath('/rss/channel/sy:UpdateBase',
+                       namespaces={
+                               'sy':'http://purl.org/rss/1.0/modules/syndication/'
+                           })
+        assert a[0].text == base