Parse Mastodon handle to add attribution and verification metadata

README.md

@@ -55,6 +55,7 @@ Bridgetown SEO Tag adds the following meta tags to your site:
 * Canonical URL
 * Next and previous URLs on paginated pages
 * [Open Graph](https://ogp.me/) title, description, site title, and URL (for Facebook, LinkedIn, etc.)
+* Mastodon [verification](https://docs.joinmastodon.org/user/profile/#verification) and [attribution](https://blog.joinmastodon.org/2024/07/highlighting-journalism-on-mastodon/)
 * [Twitter Summary Card](https://developer.twitter.com/en/docs/tweets/optimize-with-cards/guides/getting-started) metadata
 
 While you could theoretically add the necessary metadata tags yourself, Bridgetown SEO Tag provides a battle-tested template of crowdsourced best-practices.
@@ -75,6 +76,8 @@ The SEO tag will respect any of the following if included in your site's `site_m
 * `description` - A longer description used for the description meta tag. Also used as fallback for documents that don't provide their own `description` and as part of the home page title tag if `tagline` is not defined.
 * `author` - global author information (see [Advanced usage](https://github.com/bridgetownrb/bridgetown-seo-tag/wiki/Advanced-Usage#author-information))
 
+* `mastodon` - Your Mastodon handle, to both verify your Mastodon profile, and link to your profile when someone shares your content on the network. If the page metadata contains a `mastodon` entry, it will take precedence over `site_metadata.yml`.
+
 * `twitter` - You can add a single Twitter handle to be used in Twitter card tags, like "bridgetownrb". Or you use a YAML mapping with additional details:
   * `twitter:card` - The site's default card type
   * `twitter:username` - The site's Twitter handle

lib/bridgetown-seo-tag.rb

@@ -6,6 +6,7 @@
 module Bridgetown
   class SeoTag < Liquid::Tag
     autoload :AuthorDrop, "bridgetown-seo-tag/author_drop"
+    autoload :MastodonDrop, "bridgetown-seo-tag/mastodon_drop"
     autoload :ImageDrop,  "bridgetown-seo-tag/image_drop"
     autoload :UrlHelper,  "bridgetown-seo-tag/url_helper"
     autoload :Drop,       "bridgetown-seo-tag/drop"

lib/bridgetown-seo-tag/author_drop.rb

@@ -55,7 +55,7 @@ def resolved_author
         @resolved_author = sources.find { |s| !s.to_s.empty? }
       end
 
-      # If resolved_author is a string, attempts to find coresponding author
+      # If resolved_author is a string, attempts to find corresponding author
       # metadata in `site.data.authors`
       #
       # Returns a hash representing additional metadata or an empty hash

lib/bridgetown-seo-tag/drop.rb

@@ -100,7 +100,7 @@ def author
       end
 
       # Returns a Drop representing the page's image
-      # Returns nil if the image has no path, to preserve backwards compatability
+      # Returns nil if the image has no path, to preserve backwards compatibility
       def image
         @image ||= ImageDrop.new(page: page, context: @context)
         @image if @image.path

lib/bridgetown-seo-tag/image_drop.rb

@@ -24,7 +24,7 @@ def initialize(page: nil, context: nil)
         @context = context
       end
 
-      # Called path for backwards compatability, this is really
+      # Called path for backwards compatibility, this is really
       # the escaped, absolute URL representing the page's image
       # Returns nil if no image path can be determined
       def path

lib/bridgetown-seo-tag/mastodon_drop.rb

@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+module Bridgetown
+  class SeoTag
+    # A drop representing the current page's mastodon handle
+    #
+    # Mastodon handle will be pulled from:
+    #
+    # 1. The page's `mastodon` key
+    # 2. The `mastodon` key in the site config
+    class MastodonDrop < Bridgetown::Drops::Drop
+      HANDLE_REGEX = /\A@?(?<username>[^@]+)@(?<server>[^@]+)\z/
+
+      # Initialize a new MastodonDrop
+      #
+      # page - The page hash (e.g., Page#to_liquid)
+      # site - The Bridgetown::Drops::SiteDrop
+      def initialize(page: nil, site: nil)
+        raise ArgumentError unless page && site
+
+        @mutations = {}
+        @page = page
+        @site = site
+      end
+
+      def mastodon_handle
+        "@#{username}@#{server}" if handle?
+      end
+      alias_method :to_s, :mastodon_handle
+
+      def mastodon_url
+        "https://#{server}/@#{username}" if handle?
+      end
+
+      # Make the drop behave like a hash
+      def [](key)
+        return mastodon_handle if key.to_sym == :mastodon
+      end
+
+      private
+
+      attr_reader :page, :site
+
+      # Finds the mastodon handle in page.metadata, or site.metadata
+      #
+      # Returns a string
+      def resolved_handle
+        return @resolved_handle if defined? @resolved_handle
+
+        sources = [page["mastodon"]]
+        sources << site.data.dig("site_metadata", "mastodon")
+        @resolved_handle = sources.find { |s| !s.to_s.empty? }
+      end
+
+      # Returns the username parsed from the resolved handle
+      def username
+        handle_hash["username"]
+      end
+
+      # Returns the server parsed from the resolved handle
+      def server
+        handle_hash["server"]
+      end
+
+      # Returns a hash containing username and server
+      # or an empty hash, if the handle cannot be parsed
+      def handle_hash
+        @handle_hash ||= case resolved_handle
+                         when String
+                           HANDLE_REGEX.match(resolved_handle)&.named_captures || {}
+                         else
+                           {}
+                         end
+      end
+      # Since author_hash is aliased to fallback_data, any values in the hash
+      # will be exposed via the drop, allowing support for arbitrary metadata
+      alias_method :fallback_data, :handle_hash
+
+      def handle?
+        handle_hash != {}
+      end
+    end
+  end
+end

lib/bridgetown-seo-tag/url_helper.rb

@@ -9,7 +9,7 @@ module UrlHelper
       # Determines if the given string is an absolute URL
       #
       # Returns true if an absolute URL.
-      # Retruns false if it's a relative URL
+      # Returns false if it's a relative URL
       # Returns nil if it is not a string or can't be parsed as a URL
       def absolute_url?(string)
         return false unless string

lib/template.html

@@ -69,6 +69,11 @@
   <meta property="twitter:title" content="{{ seo_tag.page_title }}" />
 {% endif %}
 
+{% if seo_tag.mastodon_handle %}
+  <meta name="fediverse:creator" content="{{ seo_tag.mastodon_handle }}" />
+  <link rel="me" href="{{ seo_tag.mastodon_url }}" />
+{% endif %}
+
 {% if site.metadata.twitter %}
   <meta name="twitter:site" content="@{{ site.metadata.twitter.username | default: site.metadata.twitter | remove:'@' }}" />
 

spec/bridgetown_seo_tag/author_drop_spec.rb

@@ -143,7 +143,7 @@
     context "without an author name or handle" do
       let(:page_meta) { { "author" => { "foo" => "bar" } } }
 
-      it "dosen't blow up" do
+      it "doesn't blow up" do
         expect(subject["twitter"]).to be_nil
       end
     end

spec/bridgetown_seo_tag/mastodon_drop_spec.rb

@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+RSpec.describe Bridgetown::SeoTag::MastodonDrop do
+  let(:data) { {} }
+  let(:site_config) { {} }
+  let(:metadata_config) { { "mastodon" => "@handle@metadata.config" } }
+  let(:site) do
+    site = make_site(metadata_config, site_config)
+    site.data = site.data.merge(data)
+    site
+  end
+  let(:site_payload) { site.site_payload["site"] }
+
+  let(:page_meta) { { "title" => "page title" } }
+  let(:page)      { make_page(page_meta) }
+  subject { described_class.new(page: page.to_liquid, site: site_payload.to_liquid) }
+
+  before do
+    Bridgetown.logger.log_level = :error
+  end
+
+  it "returns the mastodon handle for #to_s" do
+    expect(subject.to_s).to eql("@handle@metadata.config")
+  end
+
+  context "with mastodon handle in site metadata" do
+    it "returns the site metadata handle" do
+      expect(subject.mastodon_handle).to eql("@handle@metadata.config")
+    end
+  end
+
+  context "with mastodon handle in front matter default" do
+    let(:site_config) do
+      {
+        "defaults" => [
+          {
+            "scope"  => { "path" => "" },
+            "values" => { "mastodon" => "@handle@frontmatter.defaults" },
+          },
+        ],
+      }
+    end
+
+    it "uses the handle from the front matter default" do
+      site # init new config
+      defaults_page = Bridgetown::SeoTag::MastodonDrop.new(page: make_resource_page.to_liquid, site: site_payload.to_liquid)
+      expect(defaults_page["mastodon"]).to eql("@handle@frontmatter.defaults")
+    end
+  end
+
+  context "with mastodon override in page meta" do
+    let(:page_meta) { { "mastodon" => "@handle@page.meta" } }
+
+    it "uses the value defined in page metadata" do
+      expect(subject["mastodon"]).to eql("@handle@page.meta")
+    end
+
+    context "with an empty value" do
+      let(:metadata_config) { {} }
+      let(:page_meta) { { "mastodon" => "" } }
+
+      it "doesn't blow up" do
+        expect(subject["mastodon"]).to be_nil
+      end
+    end
+
+    context "with a hash value" do
+      let(:page_meta) { { "mastodon" => { "some" => "thing" } } }
+
+      it "doesn't blow up" do
+        expect(subject["mastodon"]).to be_nil
+      end
+    end
+
+    context "with an array value" do
+      let(:page_meta) { { "mastodon" => [] } }
+
+      it "doesn't blow up" do
+        expect(subject["mastodon"]).to be_nil
+      end
+    end
+  end
+end