Categories and collections

README.md

@@ -140,6 +140,48 @@ Want to style what your feed looks like in the browser? Simply add an XSLT at `/
 
 Great question. In short, Atom is a better format. Think of it like RSS 3.0. For more information, see [this discussion on why we chose Atom over RSS 2.0](https://github.com/jekyll/jekyll-rss-feed/issues/2).
 
+## Categories
+
+Jekyll Feed can generate feeds for each category. Simply define which categories you'd like feeds for in your config:
+
+```yml
+feed:
+  categories:
+    - news
+    - updates
+```
+
+## Collections
+
+Jekyll Feed can generate feeds for collections other than the Posts collection. This works best for chronological collections (e.g., collections with dates in the filenames). Simply define which collections you'd like feeds for in your config:
+
+```yml
+feed:
+  collections:
+    - changes
+```
+
+By default, collection feeds will be outputted to `/feed/<COLLECTION>.xml`. If you'd like to customize the output path, specify a collection's custom path as follows:
+
+```yml
+feed:
+  collections:
+    changes:
+      path: "/changes.xml"
+```
+
+Finally, collections can also have category feeds which are outputted as `/feed/<COLLECTION>/<CATEGORY>.xml`. Specify categories like so:
+
+```yml
+feed:
+  collections:
+    changes:
+      path: "/changes.xml"
+      categories:
+        - news
+        - updates
+```
+
 ## Contributing
 
 1. Fork it (https://github.com/jekyll/jekyll-feed/fork)

lib/jekyll-feed/feed.xml

@@ -7,12 +7,20 @@
   <link href="{{ page.url | absolute_url }}" rel="self" type="application/atom+xml" />
   <link href="{{ '/' | absolute_url }}" rel="alternate" type="text/html" {% if site.lang %}hreflang="{{ site.lang }}" {% endif %}/>
   <updated>{{ site.time | date_to_xmlschema }}</updated>
-  <id>{{ '/' | absolute_url | xml_escape }}</id>
+  <id>{{ page.url | absolute_url | xml_escape }}</id>
 
-  {% if site.title %}
-    <title type="html">{{ site.title | smartify | xml_escape }}</title>
-  {% elsif site.name %}
-    <title type="html">{{ site.name | smartify | xml_escape }}</title>
+  {% assign title = site.title | default: site.name %}
+  {% if page.collection != "posts" %}
+    {% assign collection = page.collection | capitalize %}
+    {% assign title = title | append: " | " | append: collection %}
+  {% endif %}
+  {% if page.category %}
+    {% assign category = page.category | capitalize %}
+    {% assign title = title | append: " | " | append: category %}
+  {% endif %}
+
+  {% if title %}
+    <title type="html">{{ title | smartify | xml_escape }}</title>
   {% endif %}
 
   {% if site.description %}
@@ -31,7 +39,10 @@
     </author>
   {% endif %}
 
-  {% assign posts = site.posts | where_exp: "post", "post.draft != true" %}
+  {% assign posts = site[page.collection] | where_exp: "post", "post.draft != true" | sort: "date" | reverse %}
+  {% if page.category %}
+    {% assign posts = posts | where: "category",page.category %}
+  {% endif %}
   {% for post in posts limit: 10 %}
     <entry{% if post.lang %}{{" "}}xml:lang="{{ post.lang }}"{% endif %}>
       <title type="html">{{ post.title | smartify | strip_html | normalize_whitespace | xml_escape }}</title>

lib/jekyll-feed/generator.rb

@@ -8,8 +8,14 @@ class Generator < Jekyll::Generator
     # Main plugin action, called by Jekyll-core
     def generate(site)
       @site = site
-      return if file_exists?(feed_path)
-      @site.pages << content_for_file(feed_path, feed_source_path)
+      collections.each do |name, meta|
+        Jekyll.logger.info "Jekyll Feed:", "Generating feed for #{name}"
+        (meta["categories"] + [nil]).each do |category|
+          path = feed_path(:collection => name, :category => category)
+          next if file_exists?(path)
+          @site.pages << make_page(path, :collection => name, :category => category)
+        end
+      end
     end
 
     private
@@ -20,18 +26,59 @@ def generate(site)
     # We will strip all of this whitespace to minify the template
     MINIFY_REGEX = %r!(?<=>|})\s+!
 
-    # Path to feed from config, or feed.xml for default
-    def feed_path
-      if @site.config["feed"] && @site.config["feed"]["path"]
-        @site.config["feed"]["path"]
+    # Returns the plugin's config or an empty hash if not set
+    def config
+      @site.config["feed"] || {}
+    end
+
+    # Determines the destination path of a given feed
+    #
+    # collection - the name of a collection, e.g., "posts"
+    # category - a category within that collection, e.g., "news"
+    #
+    # Will return "/feed.xml", or the config-specified default feed for posts
+    # Will return `/feed/category.xml` for post categories
+    # WIll return `/feed/collection.xml` for other collections
+    # Will return `/feed/collection/category.xml` for other collection categories
+    def feed_path(collection: "posts", category: nil)
+      prefix = collection == "posts" ? "/feed" : "/feed/#{collection}"
+      if category
+        "#{prefix}/#{category}.xml"
+      elsif collections[collection] && collections[collection]["path"]
+        collections[collection]["path"]
       else
-        "feed.xml"
+        "#{prefix}.xml"
+      end
+    end
+
+    # Returns a hash representing all collections to be processed and their metadata
+    # in the form of { collection_name => { categories = [...], path = "..." } }
+    def collections
+      return @collections if defined?(@collections)
+
+      @collections = if config["collections"].is_a?(Array)
+                       config["collections"].map { |c| [c, {}] }.to_h
+                     elsif config["collections"].is_a?(Hash)
+                       config["collections"]
+                     else
+                       {}
+                     end
+
+      @collections = normalize_posts_meta(@collections)
+      @collections.each do |_name, meta|
+        meta["categories"] = (meta["categories"] || []).to_set
       end
+
+      @collections
     end
 
     # Path to feed.xml template file
     def feed_source_path
-      File.expand_path "feed.xml", __dir__
+      @feed_source_path ||= File.expand_path "feed.xml", __dir__
+    end
+
+    def feed_template
+      @feed_template ||= File.read(feed_source_path).gsub(MINIFY_REGEX, "")
     end
 
     # Checks if a file already exists in the site source
@@ -44,14 +91,29 @@ def file_exists?(file_path)
     end
 
     # Generates contents for a file
-    def content_for_file(file_path, file_source_path)
+
+    def make_page(file_path, collection: "posts", category: nil)
       file = PageWithoutAFile.new(@site, __dir__, "", file_path)
-      file.content = File.read(file_source_path).gsub(MINIFY_REGEX, "")
-      file.data["layout"] = nil
-      file.data["sitemap"] = false
-      file.data["xsl"] = file_exists?("feed.xslt.xml")
+      file.content = feed_template
+      file.data.merge!({
+        "layout"     => nil,
+        "sitemap"    => false,
+        "xsl"        => file_exists?("feed.xslt.xml"),
+        "collection" => collection,
+        "category"   => category,
+      })
       file.output
       file
     end
+
+    # Special case the "posts" collection, which, for ease of use and backwards
+    # compatability, can be configured via top-level keys or directly as a collection
+    def normalize_posts_meta(hash)
+      hash["posts"] ||= {}
+      hash["posts"]["path"] ||= config["path"]
+      hash["posts"]["categories"] ||= config["categories"]
+      config["path"] ||= hash["posts"]["path"]
+      hash
+    end
   end
 end

spec/fixtures/_collection/2018-01-01-collection-doc.md

@@ -0,0 +1,4 @@
+---
+---
+
+Look at me! I'm a collection!

spec/fixtures/_collection/2018-01-02-collection-category-doc.md

@@ -0,0 +1,5 @@
+---
+category: news
+---
+
+Look at me! I'm a collection doc in a category!

spec/fixtures/_posts/2013-12-12-dec-the-second.md

@@ -1,6 +1,7 @@
 ---
 excerpt: "Foo"
 image: "/image.png"
+category: news
 ---
 
 # December the twelfth, actually.

spec/fixtures/_posts/2014-03-02-march-the-second.md

@@ -1,5 +1,6 @@
 ---
 image: https://cdn.example.org/absolute.png?h=188&w=250
+category: news
 ---
 
 March the second!

spec/fixtures/_posts/2014-03-04-march-the-fourth.md

@@ -3,6 +3,7 @@ tags:
  - '"/><VADER>'
 image:
   path: "/object-image.png"
+category: updates
 ---
 
 March the fourth!