Make feed_meta helper collection- and category-aware

jekyll · Jan 21, 2019 · 4d58045 · 4d58045
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diff --git a/README.md b/README.md
@@ -120,6 +120,10 @@ There are several ways to convey author-specific information. Author information
 
 The plugin exposes a helper tag to expose the appropriate meta tags to support automated discovery of your feed. Simply place `{% feed_meta %}` someplace in your template's `<head>` section, to output the necessary metadata.
 
+The helper can also generate the link for a given collection: `{% feed_meta my_collection %}` or a given category: `{% feed_meta my_collection my_category %}`.
+
+To generate links for every collections and categories, call the helper using this syntax: `{% feed_meta include: all %}`.
+
 ### SmartyPants
 
 The plugin uses [Jekyll's `smartify` filter](https://jekyllrb.com/docs/templates/) for processing the site title and post titles. This will translate plain ASCII punctuation into "smart" typographic punctuation. This will not render or strip any Markdown you may be using in a title.

diff --git a/lib/jekyll-feed/meta-tag.rb b/lib/jekyll-feed/meta-tag.rb
@@ -5,17 +5,26 @@ class MetaTag < Liquid::Tag
     # Use Jekyll's native relative_url filter
     include Jekyll::Filters::URLFilters
 
+    def initialize(tag_name, args, tokens)
+      super
+      @args = args
+    end
+
     def render(context)
       @context = context
-      @generator = generator
-      links = []
-      generator.collections.each do |collection, meta|
-        (meta["categories"] + [nil]).each do |category|
-          attrs = attributes(collection, category).map { |k, v| %(#{k}="#{v}") }.join(" ")
-          links << "<link #{attrs} />"
+      if @args.strip == "include: all"
+        links = []
+        generator.collections.each do |collection, meta|
+          (meta["categories"] + [nil]).each do |category|
+            links << link(collection, category)
+          end
         end
+        links.reverse.join "\n"
+      else
+        @collection, @category = @args.split(" ")
+        @collection ||= "posts"
+        link(@collection, @category) if valid_collection && valid_category
       end
-      links.reverse.join "\n"
     end
 
     private
@@ -28,6 +37,11 @@ def generator
       @generator ||= @context.registers[:site].generators.select { |it| it.is_a? JekyllFeed::Generator }.first # rubocop:disable Metrics/LineLength
     end
 
+    def link(collection, category)
+      attrs = attributes(collection, category).map { |k, v| %(#{k}="#{v}") }.join(" ")
+      "<link #{attrs} />"
+    end
+
     def attributes(collection, category)
       href = absolute_url(generator.feed_path(:collection => collection, :category => category))
       {
@@ -41,5 +55,28 @@ def attributes(collection, category)
     def title
       config["title"] || config["name"]
     end
+
+    def valid_collection
+      return true if generator.collections.key? @collection
+
+      Jekyll.logger.warn(
+        "Jekyll Feed:",
+        "Invalid collection name. Please review `{% feed_meta #{@args} %}`"
+      )
+      false
+    end
+
+    def valid_category
+      return true if @collection == "posts" || @category.nil?
+
+      collection = generator.collections[@collection]
+      return true if collection.key?("categories") && collection["categories"].include?(@category)
+
+      Jekyll.logger.warn(
+        "Jekyll Feed:",
+        "Invalid category name. Please review `{% feed_meta #{@args} %}`"
+      )
+      false
+    end
   end
 end
diff --git a/spec/jekyll-feed_spec.rb b/spec/jekyll-feed_spec.rb
@@ -269,32 +269,6 @@
         expect(feed_meta).not_to include("title=")
       end
     end
-    context "with a collection" do
-      let(:overrides) do
-        {
-          "collections" => {
-            "collection" => {
-              "output" => true,
-            },
-          },
-          "feed"        => {
-            "collections" => {
-              "collection" => {
-                "categories" => ["news"],
-              },
-            },
-          },
-        }
-      end
-      it "renders a feed meta for each collection" do
-        default_feed    = '<link type="application/atom+xml" rel="alternate" href="http://example.org/feed.xml" title="My awesome site" />'
-        collection_feed = '<link type="application/atom+xml" rel="alternate" href="http://example.org/feed/collection.xml" title="My awesome site" />'
-        category_feed   = '<link type="application/atom+xml" rel="alternate" href="http://example.org/feed/collection/news.xml" title="My awesome site" />'
-        expect(feed_meta).to include(default_feed)
-        expect(feed_meta).to include(collection_feed)
-        expect(feed_meta).to include(category_feed)
-      end
-    end
   end
 
   context "changing the feed path" do
@@ -339,6 +313,66 @@
     end
   end
 
+  context "selecting a particular collection" do
+    let(:overrides) do
+      {
+        "collections" => {
+          "collection" => {
+            "output" => true,
+          },
+        },
+        "feed"        => {
+          "collections" => {
+            "collection" => {
+              "categories" => ["news"],
+            },
+          },
+        },
+      }
+    end
+    let(:default_feed) { Liquid::Template.parse("{% feed_meta posts %}").render!(context, {}) }
+    let(:collection_feed) { Liquid::Template.parse("{% feed_meta collection %}").render!(context, {}) }
+    let(:category_feed) { Liquid::Template.parse("{% feed_meta collection news %}").render!(context, {}) }
+
+    it "renders the feed meta for the selected collection" do
+      default_feed_link    = '<link type="application/atom+xml" rel="alternate" href="http://example.org/feed.xml" title="My awesome site" />'
+      collection_feed_link = '<link type="application/atom+xml" rel="alternate" href="http://example.org/feed/collection.xml" title="My awesome site" />'
+      category_feed_link   = '<link type="application/atom+xml" rel="alternate" href="http://example.org/feed/collection/news.xml" title="My awesome site" />'
+      expect(default_feed).to eql(default_feed_link)
+      expect(collection_feed).to eql(collection_feed_link)
+      expect(category_feed).to eql(category_feed_link)
+    end
+  end
+
+  context "requesting all feed links" do
+    let(:overrides) do
+      {
+        "collections" => {
+          "collection" => {
+            "output" => true,
+          },
+        },
+        "feed"        => {
+          "collections" => {
+            "collection" => {
+              "categories" => ["news"],
+            },
+          },
+        },
+      }
+    end
+    let(:full_feed_meta) { Liquid::Template.parse("{% feed_meta include: all %}").render!(context, {}) }
+
+    it "renders the feed meta for all collections and categories" do
+      default_feed_link    = '<link type="application/atom+xml" rel="alternate" href="http://example.org/feed.xml" title="My awesome site" />'
+      collection_feed_link = '<link type="application/atom+xml" rel="alternate" href="http://example.org/feed/collection.xml" title="My awesome site" />'
+      category_feed_link   = '<link type="application/atom+xml" rel="alternate" href="http://example.org/feed/collection/news.xml" title="My awesome site" />'
+      expect(full_feed_meta).to include(default_feed_link)
+      expect(full_feed_meta).to include(collection_feed_link)
+      expect(full_feed_meta).to include(category_feed_link)
+    end
+  end
+
   context "feed stylesheet" do
     it "includes the stylesheet" do
       expect(contents).to include('<?xml-stylesheet type="text/xml" href="http://example.org/feed.xslt.xml"?>')