From a021b96bc761bb554a2e1fc2e50057c7e5719b8b Mon Sep 17 00:00:00 2001
From: Andrew Shu <talklittle@gmail.com>
Date: Wed, 3 Feb 2021 21:24:32 -0800
Subject: [PATCH] Add RSS and Atom feeds for topic listings

---
 tildes/tildes/routes.py                       |  4 ++
 tildes/tildes/templates/base.atom.jinja2      | 14 +++++++
 tildes/tildes/templates/base.jinja2           |  3 ++
 tildes/tildes/templates/base.rss.jinja2       | 15 +++++++
 tildes/tildes/templates/home.atom.jinja2      |  6 +++
 tildes/tildes/templates/home.rss.jinja2       |  8 ++++
 .../templates/topic_listing.atom.jinja2       | 39 +++++++++++++++++++
 tildes/tildes/templates/topic_listing.jinja2  |  5 +++
 .../tildes/templates/topic_listing.rss.jinja2 | 37 ++++++++++++++++++
 tildes/tildes/views/topic.py                  | 18 ++++++++-
 10 files changed, 148 insertions(+), 1 deletion(-)
 create mode 100644 tildes/tildes/templates/base.atom.jinja2
 create mode 100644 tildes/tildes/templates/base.rss.jinja2
 create mode 100644 tildes/tildes/templates/home.atom.jinja2
 create mode 100644 tildes/tildes/templates/home.rss.jinja2
 create mode 100644 tildes/tildes/templates/topic_listing.atom.jinja2
 create mode 100644 tildes/tildes/templates/topic_listing.rss.jinja2

diff --git a/tildes/tildes/routes.py b/tildes/tildes/routes.py
index e0a197c..bd8b8f4 100644
--- a/tildes/tildes/routes.py
+++ b/tildes/tildes/routes.py
@@ -19,6 +19,8 @@ from tildes.resources.user import user_by_username
 def includeme(config: Configurator) -> None:
     """Set up application routes."""
     config.add_route("home", "/")
+    config.add_route("home_atom", "/topics.atom")
+    config.add_route("home_rss", "/topics.rss")
 
     config.add_route("search", "/search")
 
@@ -37,6 +39,8 @@ def includeme(config: Configurator) -> None:
         config.add_route("new_topic", "/new_topic", factory=group_by_path)
 
         config.add_route("group_topics", "/topics", factory=group_by_path)
+        config.add_route("group_topics_atom", "/topics.atom", factory=group_by_path)
+        config.add_route("group_topics_rss", "/topics.rss", factory=group_by_path)
 
         config.add_route("group_search", "/search", factory=group_by_path)
 
diff --git a/tildes/tildes/templates/base.atom.jinja2 b/tildes/tildes/templates/base.atom.jinja2
new file mode 100644
index 0000000..f238459
--- /dev/null
+++ b/tildes/tildes/templates/base.atom.jinja2
@@ -0,0 +1,14 @@
+{# Copyright (c) 2021 Tildes contributors <code@tildes.net> #}
+{# SPDX-License-Identifier: AGPL-3.0-or-later #}
+
+<?xml version="1.0" encoding="UTF-8" ?>
+<feed xmlns="http://www.w3.org/2005/Atom">
+
+    <title>{% block feed_title %}Tildes Atom feed{% endblock %}</title>
+    <id>{% block feed_id %}{{ request.current_route_url() }}{% endblock %}</id>
+    <link rel="self" href="{% block feed_link %}{{ request.current_route_url() }}{% endblock %}" />
+    <updated>{% block feed_updated %}{{ current_time.strftime("%Y-%m-%dT%H:%M:%SZ") }}{% endblock %}</updated>
+
+    {% block feed_entries %}{% endblock %}
+
+</feed>
diff --git a/tildes/tildes/templates/base.jinja2 b/tildes/tildes/templates/base.jinja2
index e434a03..20c7b1b 100644
--- a/tildes/tildes/templates/base.jinja2
+++ b/tildes/tildes/templates/base.jinja2
@@ -55,6 +55,9 @@
   <meta name="application-name" content="Tildes">
   <meta name="msapplication-TileColor" content="#002b36">
 
+  {# RSS/Atom feeds #}
+  {% block link_alternate_feeds %}{% endblock %}
+
   <title>{% block title_full %}{% block title %}{% endblock %} - Tildes{% endblock %}</title>
 
   {% block templates %}{% endblock %}
diff --git a/tildes/tildes/templates/base.rss.jinja2 b/tildes/tildes/templates/base.rss.jinja2
new file mode 100644
index 0000000..81e9309
--- /dev/null
+++ b/tildes/tildes/templates/base.rss.jinja2
@@ -0,0 +1,15 @@
+{# Copyright (c) 2021 Tildes contributors <code@tildes.net> #}
+{# SPDX-License-Identifier: AGPL-3.0-or-later #}
+
+<?xml version="1.0" encoding="UTF-8" ?>
+<rss version="2.0">
+
+    <channel>
+        <title>{% block channel_title %}Tildes{% endblock %}</title>
+        <link>{% block channel_link %}https://tildes.net/{% endblock %}</link>
+        <description>{% block channel_description %}Tildes RSS feed{% endblock %}</description>
+
+        {% block channel_items %}{% endblock %}
+    </channel>
+
+</rss>
diff --git a/tildes/tildes/templates/home.atom.jinja2 b/tildes/tildes/templates/home.atom.jinja2
new file mode 100644
index 0000000..31ba90e
--- /dev/null
+++ b/tildes/tildes/templates/home.atom.jinja2
@@ -0,0 +1,6 @@
+{# Copyright (c) 2021 Tildes contributors <code@tildes.net> #}
+{# SPDX-License-Identifier: AGPL-3.0-or-later #}
+
+{% extends 'topic_listing.atom.jinja2' %}
+
+{% block feed_title %}Tildes Atom feed{% endblock %}
diff --git a/tildes/tildes/templates/home.rss.jinja2 b/tildes/tildes/templates/home.rss.jinja2
new file mode 100644
index 0000000..a353007
--- /dev/null
+++ b/tildes/tildes/templates/home.rss.jinja2
@@ -0,0 +1,8 @@
+{# Copyright (c) 2021 Tildes contributors <code@tildes.net> #}
+{# SPDX-License-Identifier: AGPL-3.0-or-later #}
+
+{% extends 'topic_listing.rss.jinja2' %}
+
+{% block channel_title %}Tildes{% endblock %}
+{% block channel_link %}https://tildes.net/{% endblock %}
+{% block channel_description %}Topics RSS feed{% endblock %}
diff --git a/tildes/tildes/templates/topic_listing.atom.jinja2 b/tildes/tildes/templates/topic_listing.atom.jinja2
new file mode 100644
index 0000000..06f5150
--- /dev/null
+++ b/tildes/tildes/templates/topic_listing.atom.jinja2
@@ -0,0 +1,39 @@
+{# Copyright (c) 2021 Tildes contributors <code@tildes.net> #}
+{# SPDX-License-Identifier: AGPL-3.0-or-later #}
+
+{% extends 'base.atom.jinja2' %}
+
+{% block feed_title %}~{{ group.path }} - Tildes{% endblock %}
+
+{% block feed_entries %}
+
+    {% for topic in topics %}
+        <entry>
+            <title><![CDATA[{{ topic.title }}]]></title>
+            <id>https://tildes.net{{ topic.permalink }}</id>
+            {% if topic.is_link_type %}
+                <link rel="alternate" href="{{ topic.link }}"/>
+            {% else %}
+                <link rel="alternate" href="{{ topic.permalink }}"/>
+            {% endif %}
+            <content type="html"><![CDATA[
+                {% if topic.is_link_type %}
+                    <p>Link URL: <a href="{{ topic.link }}">{{ topic.link }}</a></p>
+                {% elif topic.is_text_type %}
+                    {{ topic.rendered_html|safe }}
+                    <hr/>
+                {% endif %}
+                <p>Comments URL: <a href="{{ topic.permalink }}">https://tildes.net{{ topic.permalink }}</a></p>
+                <p>Votes: {{ topic.num_votes }}</p>
+                <p>Comments: {{ topic.num_comments }}</p>
+            ]]></content>
+            <author><name>{{ topic.user.username }}</name></author>
+            {% if topic.last_edited_time %}
+                <updated>{{ topic.last_edited_time.strftime("%Y-%m-%dT%H:%M:%SZ") }}</updated>
+            {% else %}
+                <updated>{{ topic.created_time.strftime("%Y-%m-%dT%H:%M:%SZ") }}</updated>
+            {% endif %}
+        </entry>
+    {% endfor %}
+
+{% endblock %}
diff --git a/tildes/tildes/templates/topic_listing.jinja2 b/tildes/tildes/templates/topic_listing.jinja2
index 1f194b4..5d0a1c0 100644
--- a/tildes/tildes/templates/topic_listing.jinja2
+++ b/tildes/tildes/templates/topic_listing.jinja2
@@ -10,6 +10,11 @@
 
 {% block title %}Topics in ~{{ group.path }}{% endblock %}
 
+{% block link_alternate_feeds %}
+  <link href="{{ request.current_route_path("topics.atom") }}" type="application/atom+xml" rel="alternate" title="Topics Atom feed" />
+  <link href="{{ request.current_route_path("topics.rss") }}" type="application/rss+xml" rel="alternate" title="Topics RSS feed" />
+{% endblock %}
+
 {% block header_context_link %}
   {{ group_segmented_link(group) }}
 {% endblock %}
diff --git a/tildes/tildes/templates/topic_listing.rss.jinja2 b/tildes/tildes/templates/topic_listing.rss.jinja2
new file mode 100644
index 0000000..4baf187
--- /dev/null
+++ b/tildes/tildes/templates/topic_listing.rss.jinja2
@@ -0,0 +1,37 @@
+{# Copyright (c) 2021 Tildes contributors <code@tildes.net> #}
+{# SPDX-License-Identifier: AGPL-3.0-or-later #}
+
+{% extends 'base.rss.jinja2' %}
+
+{% block channel_title %}~{{ group.path }} - Tildes{% endblock %}
+{% block channel_link %}https://tildes.net/~{{ group.path }}{% endblock %}
+{% block channel_description %}Topics in ~{{ group.path }}{% endblock %}
+
+{% block channel_items %}
+
+    {% for topic in topics %}
+        <item>
+            <title><![CDATA[{{ topic.title }}]]></title>
+            {% if topic.is_link_type %}
+                <link>{{ topic.link }}</link>
+            {% else %}
+                <link>{{ topic.permalink }}</link>
+            {% endif %}
+            <description><![CDATA[
+                {% if topic.is_link_type %}
+                    <p>Link URL: <a href="{{ topic.link }}">{{ topic.link }}</a></p>
+                {% elif topic.is_text_type %}
+                    {{ topic.rendered_html|safe }}
+                    <hr/>
+                {% endif %}
+                <p>Comments URL: <a href="{{ topic.permalink }}">https://tildes.net{{ topic.permalink }}</a></p>
+                <p>Votes: {{ topic.num_votes }}</p>
+                <p>Comments: {{ topic.num_comments }}</p>
+            ]]></description>
+            <author>{{ topic.user.username }}</author>
+            <comments>{{ topic.permalink }}</comments>
+            <pubDate>{{ topic.created_time.strftime("%a, %d %b %Y %T %z") }}</pubDate>
+        </item>
+    {% endfor %}
+
+{% endblock %}
diff --git a/tildes/tildes/views/topic.py b/tildes/tildes/views/topic.py
index faef389..675144e 100644
--- a/tildes/tildes/views/topic.py
+++ b/tildes/tildes/views/topic.py
@@ -142,7 +142,11 @@ def post_group_topics(
 
 
 @view_config(route_name="home", renderer="home.jinja2")
+@view_config(route_name="home_atom", renderer="home.atom.jinja2")
+@view_config(route_name="home_rss", renderer="home.rss.jinja2")
 @view_config(route_name="group", renderer="topic_listing.jinja2")
+@view_config(route_name="group_topics_atom", renderer="topic_listing.atom.jinja2")
+@view_config(route_name="group_topics_rss", renderer="topic_listing.rss.jinja2")
 @use_kwargs(TopicListingSchema())
 def get_group_topics(  # noqa
     request: Request,
@@ -159,7 +163,9 @@ def get_group_topics(  # noqa
     # period needs special treatment so we can distinguish between missing and None
     period = kwargs.get("period", missing)
 
-    is_home_page = request.matched_route.name == "home"
+    is_home_page = request.matched_route.name in ["home", "home_atom", "home_rss"]
+    is_atom = request.matched_route.name in ["home_atom", "group_topics_atom"]
+    is_rss = request.matched_route.name in ["home_rss", "group_topics_rss"]
 
     if is_home_page:
         # on the home page, include topics from the user's subscribed groups
@@ -192,6 +198,11 @@ def get_group_topics(  # noqa
     if period is missing:
         period = default_settings.period
 
+    # force Newest sort order, and All Time period, for RSS feeds
+    if is_atom or is_rss:
+        order = TopicSortOption.NEW
+        period = None
+
     # set up the basic query for topics
     query = (
         request.query(Topic)
@@ -285,6 +296,11 @@ def get_group_topics(  # noqa
     else:
         financial_data = None
 
+    if is_atom:
+        request.response.content_type = "application/atom+xml"
+    if is_rss:
+        request.response.content_type = "application/rss+xml"
+
     return {
         "group": request.context,
         "groups": groups,