railslove · kangguru · Jun 9, 2017 · Jun 9, 2017 · Jun 9, 2017
diff --git a/lib/rack/tracker.rb b/lib/rack/tracker.rb
@@ -58,12 +58,7 @@ def html?; @headers['Content-Type'] =~ /html/; end
 
     def inject(env, response)
       @handlers.each(env) do |handler|
-        # Sub! is enough, in well formed html there's only one head or body tag.
-        # Block syntax need to be used, otherwise backslashes in input will mess the output.
-        # @see http://stackoverflow.com/a/4149087/518204 and https://github.com/railslove/rack-tracker/issues/50
-        response.sub! %r{</#{handler.position}>} do |m|
-          handler.render << m.to_s
-        end
+        handler.inject(response)
       end
       response
     end

diff --git a/lib/rack/tracker/google_tag_manager/google_tag_manager.rb b/lib/rack/tracker/google_tag_manager/google_tag_manager.rb
@@ -6,16 +6,29 @@ def write
     end
   end
 
-  # It is strongly recommended to put the google_tag_manager snippet only in the body tag
-  # https://developers.google.com/tag-manager/quickstart
-  self.position = :body
+  def inject(response)
+    # Sub! is enough, in well formed html there's only one head or body tag.
+    # Block syntax need to be used, otherwise backslashes in input will mess the output.
+    # @see http://stackoverflow.com/a/4149087/518204 and https://github.com/railslove/rack-tracker/issues/50
+    response.sub! %r{<head>} do |m|
+      m.to_s << self.render_head
+    end
+    response.sub! %r{<body>} do |m|
+      m.to_s << self.render_body
+    end
+    response
+  end
 
   def container
     options[:container].respond_to?(:call) ? options[:container].call(env) : options[:container]
   end
 
-  def render
-    Tilt.new( File.join( File.dirname(__FILE__), 'template', 'google_tag_manager.erb') ).render(self)
+  def render_head
+    Tilt.new( File.join( File.dirname(__FILE__), 'template', 'google_tag_manager_head.erb') ).render(self)
+  end
+
+  def render_body
+    Tilt.new( File.join( File.dirname(__FILE__), 'template', 'google_tag_manager_body.erb') ).render(self)
   end
 
   def self.track(name, *event)

diff --git a/lib/rack/tracker/google_tag_manager/template/google_tag_manager_body.erb b/lib/rack/tracker/google_tag_manager/template/google_tag_manager_body.erb
@@ -0,0 +1,4 @@
+<% if container %>
+<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=<%= container %>"
+height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
+<% end %>
diff --git a/...g_manager/template/google_tag_manager.erb → ...ager/template/google_tag_manager_head.erb b/...g_manager/template/google_tag_manager.erb → ...ager/template/google_tag_manager_head.erb
@@ -9,12 +9,9 @@ dataLayer.push(
 );
 </script>
 
-<noscript><iframe src="//www.googletagmanager.com/ns.html?id=<%= container %>"
-height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
 <script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
 new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
 j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
-'//www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
+'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
 })(window,document,'script','dataLayer','<%= container %>');</script>
-
 <% end %>
diff --git a/lib/rack/tracker/handler.rb b/lib/rack/tracker/handler.rb
@@ -23,6 +23,16 @@ def render
     raise NotImplementedError.new('needs implementation')
   end
 
+  def inject(response)
+    # Sub! is enough, in well formed html there's only one head or body tag.
+    # Block syntax need to be used, otherwise backslashes in input will mess the output.
+    # @see http://stackoverflow.com/a/4149087/518204 and https://github.com/railslove/rack-tracker/issues/50
+    response.sub! %r{</#{self.position}>} do |m|
+      self.render << m.to_s
+    end
+    response
+  end
+
   def self.track(name, event)
     raise NotImplementedError.new("class method `#{__callee__}` is not implemented.")
   end

diff --git a/spec/handler/google_tag_manager_spec.rb b/spec/handler/google_tag_manager_spec.rb
@@ -7,12 +7,6 @@ def env
     }
   end
 
-  it 'will be placed in the body by default' do
-    expect(described_class.position).to eq(:body)
-    expect(described_class.new(env).position).to eq(:body)
-    expect(described_class.new(env, position: :head).position).to eq(:head)
-  end
-
   describe "with events" do
     describe "default" do
       def env
@@ -23,15 +17,15 @@ def env
         }}
       end
 
-      subject { described_class.new(env, container: 'somebody').render }
+      subject { described_class.new(env, container: 'somebody').render_head }
       it "will show events" do
         expect(subject).to match(%r{"page":"Cart","price":50,"content_ids":\["sku_1","sku_2","sku_3"\]})
       end
     end
   end
 
   describe "with dynamic tracker" do
-    subject { described_class.new(env, { container: lambda { |env| return env[:misc] }}).render }
+    subject { described_class.new(env, { container: lambda { |env| return env[:misc] }}).render_head }
 
     it 'will call tracker lambdas to obtain tracking codes' do
       expect(subject).to match(%r{\(window,document,'script','dataLayer','foobar'\)})

diff --git a/spec/integration/google_tag_manager_integration_spec.rb b/spec/integration/google_tag_manager_integration_spec.rb
@@ -11,8 +11,9 @@
   subject { page }
 
   it "embeds the script tag with tracking event from the controller action" do
-    expect(page.find("body")).to have_content 'GTM-ABCDEF'
-    expect(page.find("body")).to have_content "dataLayer.push( {\"click\":\"X\",\"price\":10}, {\"transactionProducts\":[{\"sku\":\"DD44\",\"name\":\"T-shirt\"},{\"sku\":\"DD66\",\"name\":\"Jeans\"}]} );"
+    expect(page.find("head")).to have_content 'GTM-ABCDEF'
+    expect(page.find("head")).to have_content "dataLayer.push( {\"click\":\"X\",\"price\":10}, {\"transactionProducts\":[{\"sku\":\"DD44\",\"name\":\"T-shirt\"},{\"sku\":\"DD66\",\"name\":\"Jeans\"}]} );"
+    expect(page.find("body")).to have_xpath '//body/noscript/iframe[@src="https://www.googletagmanager.com/ns.html?id=GTM-ABCDEF"]'
   end
 
 end