Add Liquid variables _response_.url and _url_ to WebsiteAgent

app/models/agents/website_agent.rb

@@ -124,7 +124,9 @@ module Agents
 
       # Liquid Templating
 
-      In Liquid templating, the following variable is available:
+      In Liquid templating, the following variables are available except when invoked by `data_from_event`:
+
+      * `_url_`: The URL specified to fetch the content from.
 
       * `_response_`: A response object with the following keys:
 
@@ -132,6 +134,8 @@ module Agents
 
           * `headers`: Response headers; for example, `{{ _response_.headers.Content-Type }}` expands to the value of the Content-Type header.  Keys are insensitive to cases and -/_.
 
+          * `url`: The final URL of the fetched page, following redirects.
+
       # Ordering Events
 
       #{description_events_order}
@@ -328,6 +332,7 @@ module Agents
       raise "Failed: #{response.inspect}" unless consider_response_successful?(response)
 
       interpolation_context.stack {
+        interpolation_context['_url_'] = uri.to_s
         interpolation_context['_response_'] = ResponseDrop.new(response)
         handle_data(response.body, response.env[:url], existing_payload)
       }
@@ -603,6 +608,11 @@ module Agents
       def status
         @object.status
       end
+
+      # The URL
+      def url
+        @object.env.url.to_s
+      end
     end
 
     # Wraps Faraday::Utils::Headers

spec/models/agents/website_agent_spec.rb

@@ -8,6 +8,10 @@ describe Agents::WebsiteAgent do
                                            headers: {
                                              'X-Status-Message' => 'OK'
                                            })
+      stub_request(:any, /xkcd\.com\/index$/).to_return(status: 301,
+                                                        headers: {
+                                                          'Location' => 'http://xkcd.com/'
+                                                        })
       @valid_options = {
         'name' => "XKCD",
         'expected_update_period_in_days' => "2",
@@ -729,14 +733,20 @@ describe Agents::WebsiteAgent do
       end
 
       it "should interpolate _response_" do
+        @valid_options['url'] = 'http://xkcd.com/index'
         @valid_options['extract']['response_info'] =
           @valid_options['extract']['url'].merge(
-            'value' => '"{{ "The reponse was " | append:_response_.status | append:" " | append:_response_.headers.X-Status-Message | append:"." }}"'
+            'value' => '{{ "The reponse from " | append:_response_.url | append:" was " | append:_response_.status | append:" " | append:_response_.headers.X-Status-Message | append:"." | to_xpath }}'
+          )
+        @valid_options['extract']['original_url'] =
+          @valid_options['extract']['url'].merge(
+            'value' => '{{ _url_ | to_xpath }}'
           )
         @checker.options = @valid_options
         @checker.check
         event = Event.last
-        expect(event.payload['response_info']).to eq('The reponse was 200 OK.')
+        expect(event.payload['response_info']).to eq('The reponse from http://xkcd.com/ was 200 OK.')
+        expect(event.payload['original_url']).to eq('http://xkcd.com/index')
       end
 
       it "should be formatted by template after extraction" do