Merge pull request #866 from cantino/website_agent-url_on_receive

Add a url_from_event option to WebsiteAgent

CHANGES.md

@@ -1,5 +1,6 @@
 # Changes
 
+* Jun 19, 2015   - Add `url_from_event` to WebsiteAgent.
 * Jun 17, 2015   - RssAgent emits events for new feed items in chronological order.
 * Jun 15, 2015   - Liquid filter `uri_expand` added.
 * Jun 12, 2015   - RSSAgent can now accept an array of URLs.

app/models/agents/website_agent.rb

@@ -19,7 +19,7 @@ module Agents
 
       `url` can be a single url, or an array of urls (for example, for multiple pages with the exact same structure but different content to scrape)
 
-      The WebsiteAgent can also scrape based on incoming events. It will scrape the url contained in the `url` key of the incoming event payload. If you specify `merge` as the `mode`, it will retain the old payload and update it with the new values.
+      The WebsiteAgent can also scrape based on incoming events. It will scrape the url contained in the `url` key of the incoming event payload, or if you set `url_from_event` it is used as a Liquid template to generate the url to access. If you specify `merge` as the `mode`, it will retain the old payload and update it with the new values.
 
       # Supported Document Types
 
@@ -135,7 +135,8 @@ module Agents
 
     def validate_options
       # Check for required fields
-      errors.add(:base, "url and expected_update_period_in_days are required") unless options['expected_update_period_in_days'].present? && options['url'].present?
+      errors.add(:base, "either url or url_from_event is required") unless options['url'].present? || options['url_from_event'].present?
+      errors.add(:base, "expected_update_period_in_days is required") unless options['expected_update_period_in_days'].present?
       if !options['extract'].present? && extraction_type != "json"
         errors.add(:base, "extract is required for all types except json")
       end
@@ -257,7 +258,12 @@ module Agents
     def receive(incoming_events)
       incoming_events.each do |event|
         interpolate_with(event) do
-          url_to_scrape = event.payload['url']
+          url_to_scrape =
+            if url_template = options['url_from_event'].presence
+              interpolate_string(url_template)
+            else
+              event.payload['url']
+            end
           check_url(url_to_scrape,
                     interpolated['mode'].to_s == "merge" ? event.payload : {})
         end

spec/models/agents/website_agent_spec.rb

@@ -633,6 +633,17 @@ fire: hot
         }.to change { Event.count }.by(1)
       end
 
+      it "should use url_from_event as url to scrape if it exists when receiving an event" do
+        stub = stub_request(:any, 'http://example.org/?url=http%3A%2F%2Fxkcd.com')
+
+        @checker.options = @valid_options.merge(
+          'url_from_event' => 'http://example.org/?url={{url | uri_escape}}'
+        )
+        @checker.receive([@event])
+
+        expect(stub).to have_been_requested
+      end
+
       it "should interpolate values from incoming event payload" do
         expect {
           @valid_options['extract'] = {