Merge pull request #211 from 8parth/master

use canonical_url specified in page if present

README.md

@@ -224,3 +224,30 @@ defaults:
 ### SmartyPants Titles
 
 Titles will be processed using [Jekyll's `smartify` filter](https://jekyllrb.com/docs/templates/). This will use SmartyPants to translate plain ASCII punctuation into "smart" typographic punctuation. This will not render or strip any Markdown you may be using in a page title.
+
+### Setting customized Canonical URL
+
+You can set custom Canonical URL for a page by specifying canonical_url option in page front-matter.
+E.g., you have the following in the page's front matter:
+```yml
+layout: post
+title: Title of Your Post
+canonical_url: 'https://github.com/jekyll/jekyll-seo-tag/'
+```
+
+Which will generate canonical_url with specified link in canonical_url.
+```html
+<link rel="canonical" href="https://github.com/jekyll/jekyll-seo-tag/" />
+```
+
+If no canonical_url option was specified, then uses page url for generating canonical_url.
+E.g., you have not specified canonical_url in front-matter:
+```yml
+layout: post
+title: Title of Your Post
+```
+
+Which will generate following canonical_url:
+```html
+<link rel="canonical" href="http://yoursite.com/title-of-your-post" />
+```

lib/jekyll-seo-tag/drop.rb

@@ -183,7 +183,11 @@ module Jekyll
 
       def canonical_url
         @canonical_url ||= begin
-          filters.absolute_url(page["url"]).to_s.gsub(%r!/index\.html$!, "/")
+          if page["canonical_url"].to_s.empty?
+            filters.absolute_url(page["url"]).to_s.gsub(%r!/index\.html$!, "/")
+          else
+            page["canonical_url"]
+          end
         end
       end
 

spec/jekyll_seo_tag/drop_spec.rb

@@ -624,4 +624,23 @@ RSpec.describe Jekyll::SeoTag::Drop do
       end
     end
   end
+
+  context "canonical url" do
+    let(:config) { { :url => "http://example.com" } }
+
+    context "when canonical url is specified for a page" do
+      let(:canonical_url) { "https://github.com/jekyll/jekyll-seo-tag/" }
+      let(:page_meta) { { "title" => "page title", "canonical_url" => canonical_url } }
+
+      it "uses specified canonical url" do
+        expect(subject.canonical_url).to eq(canonical_url)
+      end
+    end
+
+    context "when canonical url is not specified for a page" do
+      it "uses site specific canonical url" do
+        expect(subject.canonical_url).to eq("http://example.com/page.html")
+      end
+    end
+  end
 end