1 files changed, 75 insertions, 0 deletions
diff --git a/_plugins/article.rb b/_plugins/article.rb
new file mode 100644
index 0000000..3107b4a
--- /dev/null
+++ b/_plugins/article.rb
@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+# Copyright (C) 2019 Miquel Sabaté Solà <mikisabate@gmail.com>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+require "time"
+require_relative "render_helper"
+
+module Jekyll
+  # Render og:type related tags.
+  class RenderTypeTags < Liquid::Tag
+    include ::Jekyll::RenderHelper
+
+    def render(context)
+      if ["posts"].include?(context["page"]["collection"])
+        render_article_tags(context["page"])
+      else
+        '<meta property="og:type" content="website" />'
+      end
+    end
+
+    protected
+
+    # Render all the tags related to the article og:type.
+    def render_article_tags(page)
+      tags = page["tags"].inject("") { |acc, t| acc + render_meta("article:tag", t) }
+
+      '<meta property="og:type" content="article" />' +
+        render_meta("og:author", "Miquel Sabaté Solà") +
+        render_meta("profile:first_name", "Miquel") +
+        render_meta("profile:last_name", "Sabaté Solà") +
+        render_meta("profile:username", "mssola") +
+        render_meta("profile:gender", "male") +
+        render_meta("article:section", page["collection"]) +
+        render_meta("article:published_time", published_time(page)) +
+        render_meta("article:modified_time", modified_time(page)) +
+        tags
+    end
+
+    # Returns the published time of the given page.
+    def published_time(page)
+      # We could do fancy stuff like using DateTime.strptime and so on, but
+      # Jekyll completely disregards the hour, minutes, etc., so why bother.
+      page["date"].to_s.split.first
+    end
+
+    # Returns the modified time of the given page.
+    def modified_time(page)
+      path = File.expand_path(File.join(File.dirname(__FILE__), "..", page["path"]))
+      out  = `git log -n 1 --pretty='format:%cd' --date=iso8601-strict -- #{path}`
+
+      begin
+        Time.iso8601(out)
+        out
+      rescue ArgumentError => e
+        puts "[WARNING] Could not parse the given modified time from Git: #{e}"
+        nil
+      end
+    end
+  end
+end
+
+Liquid::Template.register_tag("render_type_tags", Jekyll::RenderTypeTags)