From 1413aa153a256c24fe72d881005df500d5549f44 Mon Sep 17 00:00:00 2001
From: Kieran Eglin <kieran.eglin@gmail.com>
Date: Sat, 23 Mar 2024 19:02:46 -0700
Subject: [PATCH] [WIP] got basic podcast RSS working

---
 lib/pinchflat/podcasts/rss_feed_builder.ex    | 68 +++++++++++--------
 .../controllers/sources/source_controller.ex  | 14 ++++
 lib/pinchflat_web/router.ex                   |  1 +
 3 files changed, 53 insertions(+), 30 deletions(-)

diff --git a/lib/pinchflat/podcasts/rss_feed_builder.ex b/lib/pinchflat/podcasts/rss_feed_builder.ex
index 45f07ed..d7b041b 100644
--- a/lib/pinchflat/podcasts/rss_feed_builder.ex
+++ b/lib/pinchflat/podcasts/rss_feed_builder.ex
@@ -1,6 +1,7 @@
 defmodule Pinchflat.Podcasts.RssFeedBuilder do
   @datetime_format "%a, %d %b %Y %H:%M:%S %z"
 
+  # TODO: test
   # TODO: only MIs that are confirmed to exist on-disk should be provided
   def build(source, media_items) do
     media_item_xml = Enum.map(media_items, &build_media_item_xml(source, &1))
@@ -8,41 +9,20 @@ defmodule Pinchflat.Podcasts.RssFeedBuilder do
     build_source_xml(source, media_item_xml)
   end
 
-  defp build_media_item_xml(source, media_item) do
-    # NOTE: improvements for future:
-    # - Add <itunes:duration>
-    # - Serve proper images instead of the placeholders
-    """
-    <item>
-      <guid isPermaLink="false">#{media_item.uuid}</guid>
-      <title>#{media_item.title}</title>
-      <link>#{media_item.original_url}</link>
-      <description>#{media_item.description}</description>
-      <pubDate>#{generate_upload_date(media_item)}</pubDate>
-      <enclosure
-        url="#{generate_media_stream_path(media_item)}"
-        length="#{media_item.media_size_bytes}"
-        type="#{determine_content_type(media_item)}">
-      </enclosure>
-      <itunes:author>#{source.custom_name}</itunes:author>
-      <itunes:subtitle>#{media_item.title}</itunes:subtitle>
-      <itunes:summary><![CDATA[#{media_item.description}]]></itunes:summary>
-      <itunes:image href="https://raw.githubusercontent.com/kieraneglin/pinchflat/master/priv/static/images/originals/logo.png"></itunes:image>
-      <itunes:explicit>false</itunes:explicit>
-    </item>
-    """
-  end
-
   defp build_source_xml(source, media_item_xml) do
-    # Useful: https://validator.w3.org/feed/#validate_by_input
-    # NOTE: improvements for future:
+    # Useful: resources:
+    #   - https://validator.w3.org/feed/#validate_by_input
+    #   - https://github.com/Podcastindex-org/podcast-namespace/blob/main/docs/1.0.md
+    #   - https://podba.se/validate
+    #
     # - Add real <description>
-    # - Add <itunes:summary>
     # - Serve proper images instead of the placeholders
-    # - Ass <atom:link href="<LINK TO FEED>" rel="self" type="application/rss+xml" />
     """
     <?xml version="1.0" encoding="UTF-8"?>
-    <rss version="2.0" xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd">
+    <rss version="2.0"
+      xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd"
+      xmlns:podcast="https://podcastindex.org/namespace/1.0"
+      xmlns:atom="http://www.w3.org/2005/Atom">
       <channel>
         <title>#{source.custom_name}</title>
         <link>#{source.original_url}</link>
@@ -52,6 +32,9 @@ defmodule Pinchflat.Podcasts.RssFeedBuilder do
         <language>en-us</language>
         <lastBuildDate>#{Calendar.strftime(DateTime.utc_now(), @datetime_format)}</lastBuildDate>
         <pubDate>#{Calendar.strftime(source.inserted_at, @datetime_format)}</pubDate>
+        <atom:link href="#{generate_self_link(source)}" rel="self" type="application/rss+xml" />
+        <podcast:locked>false</podcast:locked>
+        <podcast:guid>#{source.uuid}</podcast:guid>
         <image>
           <url>https://raw.githubusercontent.com/kieraneglin/pinchflat/master/priv/static/images/originals/logo.png</url>
           <title>#{source.custom_name}</title>
@@ -71,6 +54,31 @@ defmodule Pinchflat.Podcasts.RssFeedBuilder do
     """
   end
 
+  defp build_media_item_xml(source, media_item) do
+    """
+    <item>
+      <guid isPermaLink="false">#{media_item.uuid}</guid>
+      <title>#{media_item.title}</title>
+      <link>#{media_item.original_url}</link>
+      <description>#{media_item.description}</description>
+      <pubDate>#{generate_upload_date(media_item)}</pubDate>
+      <enclosure
+        url="#{generate_media_stream_path(media_item)}"
+        length="#{media_item.media_size_bytes}"
+        type="#{determine_content_type(media_item)}">
+      </enclosure>
+      <itunes:author>#{source.custom_name}</itunes:author>
+      <itunes:subtitle>#{media_item.title}</itunes:subtitle>
+      <itunes:summary><![CDATA[#{media_item.description}]]></itunes:summary>
+      <itunes:explicit>false</itunes:explicit>
+    </item>
+    """
+  end
+
+  defp generate_self_link(source) do
+    "#{url_base()}/sources/#{source.uuid}/feed.xml"
+  end
+
   defp generate_media_stream_path(media_item) do
     extension = Path.extname(media_item.media_filepath)
 
diff --git a/lib/pinchflat_web/controllers/sources/source_controller.ex b/lib/pinchflat_web/controllers/sources/source_controller.ex
index 3211ccc..ae5b3f1 100644
--- a/lib/pinchflat_web/controllers/sources/source_controller.ex
+++ b/lib/pinchflat_web/controllers/sources/source_controller.ex
@@ -7,6 +7,7 @@ defmodule PinchflatWeb.Sources.SourceController do
   alias Pinchflat.Sources
   alias Pinchflat.Profiles
   alias Pinchflat.Sources.Source
+  alias Pinchflat.Podcasts.RssFeedBuilder
 
   def index(conn, _params) do
     sources = Repo.preload(Sources.list_sources(), :media_profile)
@@ -58,6 +59,19 @@ defmodule PinchflatWeb.Sources.SourceController do
     )
   end
 
+  def feed(conn, %{"id" => uuid}) do
+    # TODO: change this to UUID
+    source = Repo.get_by!(Source, id: uuid)
+    media_items = Media.list_downloaded_media_items_for(source, limit: 100)
+
+    xml = RssFeedBuilder.build(source, media_items)
+
+    conn
+    |> put_resp_content_type("application/rss+xml")
+    |> put_resp_header("content-disposition", "inline")
+    |> send_resp(200, xml)
+  end
+
   def edit(conn, %{"id" => id}) do
     source = Sources.get_source!(id)
     changeset = Sources.change_source(source)
diff --git a/lib/pinchflat_web/router.ex b/lib/pinchflat_web/router.ex
index 0aff573..c452b58 100644
--- a/lib/pinchflat_web/router.ex
+++ b/lib/pinchflat_web/router.ex
@@ -36,6 +36,7 @@ defmodule PinchflatWeb.Router do
   # TODO: consider putting the basic auth here behind a config flag
   # so people that want RSS feeds to work can enable it.
   scope "/", PinchflatWeb do
+    get "/sources/:id/feed", Sources.SourceController, :feed
     get "/media/:id/stream", MediaItems.MediaItemController, :stream
   end