generation of rss feed

2 files changed, 70 insertions, 6 deletions

diff --git a/watchnews/rss.py b/watchnews/rss.py
new file mode 100644
index 0000000..30510c2
--- /dev/null
+++ b/watchnews/rss.py
@@ -0,0 +1,50 @@
+from . import data
+from .web import Difftable
+
+
+from ll.xist import xsc, parse
+from ll.xist.ns import xml, rss20
+
+
+def rss():
+    versions = data.Version.raw("""\
+SELECT * 
+FROM version v
+WHERE EXISTS (SELECT 1 
+              FROM version v2
+              WHERE v2.id != v.id 
+                AND v2.item_id == v.item_id
+                AND v2.created_date < v.created_date)
+ORDER BY v.created_date DESC
+LIMIT 30""")
+
+    items = []
+    for to_version in versions:
+        from_version = data.Version.select() \
+            .where((data.Version.id != to_version.id) &
+                   (data.Version.item == to_version.item) &
+                   (data.Version.created_date < to_version.created_date)) \
+            .order_by(data.Version.created_date.desc()) \
+            .first()
+
+        difftable = Difftable(to_version, from_version,
+                              inline_style=True).string("utf-8")
+        items.append(rss20.item(
+            rss20.title(
+                "{} - {}".format(to_version.item.feed.title, to_version.title)),
+            rss20.author(to_version.authors),
+            rss20.pubDate(to_version.created_date.strftime(
+                "%a, %d %b %Y %T %z")),
+            rss20.guid("from={},to={}".format(from_version.id, to_version.id)),
+            rss20.link(to_version.url),
+            rss20.description(
+                xsc.Text(difftable)
+            )
+        ))
+    return xsc.Frag(xml.XML(), rss20.rss(
+        rss20.channel(
+            rss20.title("Watchnews change report"),
+            *items
+        )
+    )
+    ).string("utf-8")
diff --git a/watchnews/web.py b/watchnews/web.py
index 438e649..05ffcdc 100644
--- a/watchnews/web.py
+++ b/watchnews/web.py
@@ -9,6 +9,8 @@ import difflib
 
 
 class DiffSupport:
+    def __init__(self):
+        self.inline_style = False
 
     def _diff(self, line1, line2):
         diff = list(difflib._mdiff([line1], [line2]))
@@ -27,21 +29,31 @@ class DiffSupport:
                 html.td(*self._format_diff(diff2))
             ))
         return html.table(rows, **{'class': 'textdiff'})
-
+     
     def _format_diff(self, line):
+        actionclass = {
+            '+': 'diff_add', 
+            '-': 'diff_sub',
+            '^': 'diff_chg'}
+        actionname = {
+            '+': 'i',
+            '-': 'strike',
+            '^': 'strong'}
         elems = []
         nextpos = line.find("\x00")
         while nextpos != -1 and nextpos + 1 < len(line):
-            actionclass = {
-                '+': 'diff_add', '-': 'diff_sub',
-                '^': 'diff_chg'}[line[nextpos + 1]]
             endpos = line.find("\x01", nextpos + 2)
 
             if nextpos != 0:  # intermediate unchanged text
                 elems += [html.span(line[:nextpos])]
 
             text = line[nextpos + 2:endpos]
-            elems += [html.span(text, **{'class': actionclass})]
+            if self.inline_style:
+                elem = html.span(text)
+                elem.xmlname = actionname[line[nextpos+1]]
+                elems += [elem]
+            else:
+                elems += [html.span(text, **{'class':actionclass[line[nextpos+1]]})]
 
             line = line[endpos:]
             nextpos = line.find("\x00")
@@ -53,8 +65,10 @@ class DiffSupport:
 
 class Difftable(html.div, DiffSupport):
 
-    def __init__(self, to_version, from_version=None):
+    def __init__(self, to_version, from_version=None, inline_style=False):
         super().__init__()
+        self.xmlname = "div"
+        self.inline_style = inline_style
         if from_version == None:
             self.single_version(to_version)
         else: