Turn wikimedia_commons values into links

This turns the value of the 'wikimedia_commons' tag into a link to the
respective page on commons.wikimedia.org (if it is a 'File:' or 'Category:'
item) by enhancing the browse tags helper. See [1] for the tag description.

[1] http://wiki.openstreetmap.org/wiki/Key:wikimedia_commons

app/helpers/browse_tags_helper.rb

@@ -17,6 +17,8 @@ module BrowseTagsHelper
         link_to(w[:title], w[:url], :title => t("browse.tag_details.wikidata_link", :page => w[:title].strip))
       end
       safe_join(wdt, ";")
+    elsif wmc = wikimedia_commons_link(key, value)
+      link_to h(wmc[:title]), wmc[:url], :title => t("browse.tag_details.wikimedia_commons_link", :page => wmc[:title])
     elsif url = wiki_link("tag", "#{key}=#{value}")
       link_to h(value), url, :title => t("browse.tag_details.wiki_link.tag", :key => key, :value => value)
     elsif phones = telephone_links(key, value)
@@ -111,6 +113,16 @@ module BrowseTagsHelper
     nil
   end
 
+  def wikimedia_commons_link(key, value)
+    if key == "wikimedia_commons" && value =~ /^(?:file|category):/i
+      return {
+        :url => "//commons.wikimedia.org/wiki/#{value}?uselang=#{I18n.locale}",
+        :title => value
+      }
+    end
+    nil
+  end
+
   def telephone_links(_key, value)
     # Does it look like a global phone number? eg "+1 (234) 567-8901 "
     # or a list of alternate numbers separated by ;

config/locales/en.yml

@@ -278,6 +278,7 @@ en:
         tag: "The wiki description page for the %{key}=%{value} tag"
       wikidata_link: "The %{page} item on Wikidata"
       wikipedia_link: "The %{page} article on Wikipedia"
+      wikimedia_commons_link: "The %{page} item on Wikimedia Commons"
       telephone_link: "Call %{phone_number}"
       colour_preview: "Colour %{colour_value} preview"
     note:

test/helpers/browse_tags_helper_test.rb

@@ -48,6 +48,9 @@ class BrowseTagsHelperTest < ActionView::TestCase
     html = format_value("name:etymology:wikidata", "Q123")
     assert_dom_equal "<a title=\"The Q123 item on Wikidata\" href=\"//www.wikidata.org/entity/Q123?uselang=en\">Q123</a>", html
 
+    html = format_value("wikimedia_commons", "File:Test.jpg")
+    assert_dom_equal "<a title=\"The File:Test.jpg item on Wikimedia Commons\" href=\"//commons.wikimedia.org/wiki/File:Test.jpg?uselang=en\">File:Test.jpg</a>", html
+
     html = format_value("colour", "#f00")
     assert_dom_equal %(<span class="colour-preview-box" data-colour="#f00" title="Colour #f00 preview"></span>#f00), html
   end
@@ -190,6 +193,34 @@ class BrowseTagsHelperTest < ActionView::TestCase
     assert_nil link
   end
 
+  def test_wikimedia_commons_link
+    link = wikimedia_commons_link("wikimedia_commons", "http://commons.wikimedia.org/wiki/File:Full%20URL.jpg")
+    assert_nil link
+
+    link = wikimedia_commons_link("wikimedia_commons", "https://commons.wikimedia.org/wiki/File:Full%20URL.jpg")
+    assert_nil link
+
+    link = wikimedia_commons_link("wikimedia_commons", "Test.jpg")
+    assert_nil link
+
+    link = wikimedia_commons_link("wikimedia_commons", "File:Test.jpg")
+    assert_equal "//commons.wikimedia.org/wiki/File:Test.jpg?uselang=en", link[:url]
+    assert_equal "File:Test.jpg", link[:title]
+
+    link = wikimedia_commons_link("wikimedia_commons", "Category:Test_Category")
+    assert_equal "//commons.wikimedia.org/wiki/Category:Test_Category?uselang=en", link[:url]
+    assert_equal "Category:Test_Category", link[:title]
+
+    I18n.locale = "pt-BR"
+
+    link = wikimedia_commons_link("wikimedia_commons", "File:Test.jpg")
+    assert_equal "//commons.wikimedia.org/wiki/File:Test.jpg?uselang=pt-BR", link[:url]
+    assert_equal "File:Test.jpg", link[:title]
+
+    link = wikimedia_commons_link("foo", "Test")
+    assert_nil link
+  end
+
   def test_telephone_links
     links = telephone_links("foo", "Test")
     assert_nil links