Use canonical-rails gem to generate canonical URLs

Gemfile

@@ -95,6 +95,9 @@ gem "kgio"
 # Load secure_headers for Content-Security-Policy support
 gem "secure_headers"
 
+# Load canonical-rails to generate canonical URLs
+gem "canonical-rails"
+
 # Used to generate logstash friendly log files
 gem "logstasher"
 

Gemfile.lock

@@ -42,11 +42,13 @@ GEM
       public_suffix (~> 2.0, >= 2.0.2)
     arel (6.0.4)
     ast (2.3.0)
-    autoprefixer-rails (6.7.5)
+    autoprefixer-rails (6.7.7.1)
       execjs
     bigdecimal (1.1.0)
     builder (3.2.3)
-    capybara (2.12.1)
+    canonical-rails (0.1.2)
+      rails (>= 4.1, < 5.1)
+    capybara (2.13.0)
       addressable
       mime-types (>= 1.16)
       nokogiri (>= 1.3.3)
@@ -67,7 +69,7 @@ GEM
     colorize (0.8.1)
     composite_primary_keys (8.1.4)
       activerecord (~> 4.2.0)
-    concurrent-ruby (1.0.4)
+    concurrent-ruby (1.0.5)
     coveralls (0.8.19)
       json (>= 1.8, < 3)
       simplecov (~> 0.12.0)
@@ -89,9 +91,9 @@ GEM
     factory_girl_rails (4.8.0)
       factory_girl (~> 4.8.0)
       railties (>= 3.0.0)
-    faraday (0.10.1)
+    faraday (0.11.0)
       multipart-post (>= 1.2, < 3)
-    fspath (3.0.3)
+    fspath (3.1.0)
     geoip (1.6.3)
     globalid (0.3.7)
       activesupport (>= 4.1.0)
@@ -100,7 +102,7 @@ GEM
     htmlentities (4.3.4)
     http_accept_language (2.0.5)
     i18n (0.8.1)
-    i18n-js (3.0.0.rc15)
+    i18n-js (3.0.0.rc16)
       i18n (~> 0.6, >= 0.6.6)
     image_optim (0.24.2)
       exifr (~> 1.2, >= 1.2.2)
@@ -108,13 +110,13 @@ GEM
       image_size (~> 1.5)
       in_threads (~> 1.3)
       progress (~> 3.0, >= 3.0.1)
-    image_optim_rails (0.2.0)
+    image_optim_rails (0.3.0)
       image_optim (~> 0.24.0)
       rails
       sprockets
     image_size (1.5.0)
-    in_threads (1.3.1)
+    in_threads (1.4.0)
-    jquery-rails (4.2.2)
+    jquery-rails (4.3.1)
       rails-dom-testing (>= 1, < 3)
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
@@ -138,11 +140,10 @@ GEM
       sprockets (>= 2, < 4)
       sprockets-rails (>= 2, < 4)
       tilt
-    libv8 (3.16.14.17)
+    libv8 (3.16.14.19)
     libxml-ruby (3.0.0)
     logstash-event (1.2.02)
-    logstasher (1.1.1)
+    logstasher (1.2.1)
-      activerecord (>= 4.0)
       activesupport (>= 4.0)
       logstash-event (~> 1.2.0)
       request_store
@@ -159,7 +160,7 @@ GEM
     multi_json (1.12.1)
     multi_xml (0.6.0)
     multipart-post (2.0.0)
-    nokogiri (1.7.0.1)
+    nokogiri (1.7.1)
       mini_portile2 (~> 2.1.0)
     nokogumbo (1.4.9)
       nokogiri
@@ -211,8 +212,8 @@ GEM
       mimemagic (= 0.3.0)
     parser (2.4.0.0)
       ast (~> 2.2)
-    pg (0.19.0)
+    pg (0.20.0)
-    poltergeist (1.13.0)
+    poltergeist (1.14.0)
       capybara (~> 2.1)
       cliver (~> 0.3.1)
       websocket-driver (>= 0.2.0)
@@ -283,7 +284,7 @@ GEM
       sprockets (>= 2.8, < 4.0)
       sprockets-rails (>= 2.0, < 4.0)
       tilt (>= 1.1, < 3)
-    secure_headers (3.6.1)
+    secure_headers (3.6.2)
       useragent
     simplecov (0.12.0)
       docile (~> 1.1.0)
@@ -304,12 +305,12 @@ GEM
       ref
     thor (0.19.4)
     thread_safe (0.3.6)
-    tilt (2.0.6)
+    tilt (2.0.7)
     timecop (0.8.1)
     tins (1.13.2)
     tzinfo (1.2.2)
       thread_safe (~> 0.1)
-    uglifier (3.0.4)
+    uglifier (3.1.9)
       execjs (>= 0.3.0, < 3)
     unicode-display_width (1.1.3)
     useragent (0.16.8)
@@ -334,6 +335,7 @@ DEPENDENCIES
   actionpack-page_caching
   autoprefixer-rails
   bigdecimal (~> 1.1.0)
+  canonical-rails
   coffee-rails (~> 4.1.0)
   composite_primary_keys (~> 8.1.0)
   coveralls

app/views/layouts/_head.html.erb

@@ -24,7 +24,7 @@
   <%= tag("meta", { :name => "msapplication-TileColor", :content => "#00a300" }) %>
   <%= tag("meta", { :name => "msapplication-TileImage", :content => image_path("mstile-144x144.png") }) %>
   <%= tag("meta", { :name => "theme-color", :content => "#ffffff" }) %>
-  <%= tag("link", { :rel => "canonical", :href => root_url(:host => SERVER_URL) }) %>
+  <%= canonical_tag %>
   <%= tag("link", { :rel => "publisher", :href => "https://plus.google.com/111953119785824514010" }) %>
   <%= tag("link", { :rel => "search", :type => "application/opensearchdescription+xml", :title => "OpenStreetMap Search", :href => asset_path("osm.xml") }) %>
   <%= tag("meta", { :name => "description", :content => "OpenStreetMap is the free wiki world map." }) %>

config/initializers/canonical_rails.rb

@@ -0,0 +1,22 @@
+CanonicalRails.setup do |config|
+  # Force the protocol. If you do not specify, the protocol will be based on the incoming request's protocol.
+
+  # config.protocol#= 'https://'
+
+  # This is the main host, not just the TLD, omit slashes and protocol. If you have more than one, pick the one you want to rank in search results.
+
+  config.host = SERVER_URL
+
+  # http://en.wikipedia.org/wiki/URL_normalization
+  # Trailing slash represents semantics of a directory, ie a collection view - implying an :index get route;
+  # otherwise we have to assume semantics of an instance of a resource type, a member view - implying a :show get route
+  #
+  # Acts as a whitelist for routes to have trailing slashes
+
+  config.collection_actions = [:index]
+
+  # Parameter spamming can cause index dilution by creating seemingly different URLs with identical or near-identical content.
+  # Unless whitelisted, these parameters will be omitted
+
+  config.whitelisted_parameters = []
+end