Add support for atom / rss feedHEADmaster

Date format was changed to support `updated` in ISO format. Now every
post will require date and time, which might be a usability regression,
but we'll see. Also, `updated` field was introduced in metadata. If
there is no such field, them date field will be used instead.

1 files changed, 34 insertions, 0 deletions

diff --git a/blog/atom.py b/blog/atom.py
new file mode 100644
index 0000000..e6d836c
--- /dev/null
+++ b/blog/atom.py
@@ -0,0 +1,34 @@
+import os
+import datetime
+import functools
+from typing import List
+
+from jinja2 import Template
+
+import render
+from post import Post, remove_drafts
+
+
+class Atom(object):
+    template: Template
+    posts: List[Post]
+
+    def __init__(self, template: Template, posts: List[Post]) -> None:
+        self.template = template
+        self.posts = remove_drafts(posts)
+
+    @staticmethod
+    def _now() -> datetime.datetime:
+        now = datetime.datetime.now(datetime.timezone.utc)
+        return now.replace(microsecond=0)
+
+    @functools.cached_property
+    def updated(self) -> datetime.datetime:
+        if not self.posts:
+            return self._now()
+        return self.posts[0].metadata.updated
+
+    def generate(self, basedir: str) -> None:
+        atom = os.path.join(basedir, "atom.xml")
+        rendered = self.template.render(updated=self.updated, posts=self.posts)
+        render.write_file_content(atom, rendered)