Allow before_playback/record hooks to prevent playback/recording by c…

…alling #ignore! on the yielded interaction.

features/configuration/hooks.feature

@@ -8,9 +8,14 @@ Feature: Hooks
 
   To use these, call `config.before_record` or `config.before_playback` in
   your `VCR.config` block.  Provide a block that accepts 0, 1 or 2 arguments.
+
   The first argument, if the block accepts it, will be an HTTP interaction.
   Changes you make to the interaction will be reflected in the recording or
-  playback.  The second argument, if the block accepts it, will be the
+  playback.  You can also call `#ignore!` on the interaction to cause VCR to
+  ignore it.  It will not be recorded or played back (depending on which
+  kind of hook you use).
+
+  The second argument, if the block accepts it, will be the
   `VCR::Cassette` instance.  This may be useful for hooks that you want to
   behave differently for different cassettes.
 
@@ -82,6 +87,32 @@ Feature: Hooks
     Then the file "cassettes/recording_example.yml" should contain "body: Hello World"
      And the file "cassettes/recording_example.yml" should not contain "secret"
 
+  Scenario: Prevent recording by ignoring interaction in before_record hook
+    Given a file named "before_record_ignore.rb" with:
+      """
+      require 'vcr_cucumber_helpers'
+
+      start_sinatra_app(:port => 7777) do
+        get('/') { "Hello World" }
+      end
+
+      require 'vcr'
+
+      VCR.config do |c|
+        c.stub_with :fakeweb
+        c.cassette_library_dir = 'cassettes'
+        c.before_record { |i| i.ignore! }
+      end
+
+      VCR.use_cassette('recording_example', :record => :new_episodes) do
+        response = Net::HTTP.get_response('localhost', '/', 7777)
+        puts "Response: #{response.body}"
+      end
+      """
+    When I run "ruby before_record_ignore.rb"
+    Then it should pass with "Response: Hello World"
+    And the file "cassettes/recording_example.yml" should not exist
+
   Scenario: Change playback with before_playback hook
     Given a file named "before_playback_example.rb" with:
       """
@@ -104,6 +135,52 @@ Feature: Hooks
     When I run "ruby before_playback_example.rb"
     Then it should pass with "Response: response from before_playback"
 
+  Scenario: Prevent playback by ignoring interaction in before_playback hook
+    Given a previously recorded cassette file "cassettes/localhost.yml" with:
+      """
+      ---
+      - !ruby/struct:VCR::HTTPInteraction
+        request: !ruby/struct:VCR::Request
+          method: :get
+          uri: http://localhost:7777/
+          body:
+          headers:
+        response: !ruby/struct:VCR::Response
+          status: !ruby/struct:VCR::ResponseStatus
+            code: 200
+            message: OK
+          headers:
+            content-type:
+            - text/html;charset=utf-8
+            content-length:
+            - "20"
+          body: recorded response
+          http_version: "1.1"
+      """
+    And a file named "before_playback_ignore.rb" with:
+      """
+      require 'vcr_cucumber_helpers'
+
+      start_sinatra_app(:port => 7777) do
+        get('/') { "sinatra response" }
+      end
+
+      require 'vcr'
+
+      VCR.config do |c|
+        c.stub_with                :fakeweb
+        c.cassette_library_dir     = 'cassettes'
+        c.before_playback { |i| i.ignore! }
+      end
+
+      VCR.use_cassette('localhost', :record => :new_episodes) do
+        response = Net::HTTP.get_response('localhost', '/', 7777)
+        puts "Response: #{response.body}"
+      end
+      """
+    When I run "ruby before_playback_ignore.rb"
+    Then it should pass with "Response: sinatra response"
+
   Scenario: Multiple hooks are run in order
     Given a file named "multiple_hooks.rb" with:
       """

lib/vcr/cassette.rb

@@ -145,18 +145,22 @@ def merged_interactions
     end
 
     def write_recorded_interactions_to_disk
-      if VCR::Config.cassette_library_dir && new_recorded_interactions.size > 0
-        directory = File.dirname(file)
-        FileUtils.mkdir_p directory unless File.exist?(directory)
-        interactions = merged_interactions
-        invoke_hook(:before_record, interactions)
-        File.open(file, 'w') { |f| f.write interactions.to_yaml }
-      end
+      return unless VCR::Config.cassette_library_dir
+      return if new_recorded_interactions.empty?
+
+      interactions = merged_interactions
+      invoke_hook(:before_record, interactions)
+      return if interactions.empty?
+
+      directory = File.dirname(file)
+      FileUtils.mkdir_p directory unless File.exist?(directory)
+      File.open(file, 'w') { |f| f.write interactions.to_yaml }
     end
 
     def invoke_hook(type, interactions)
-      interactions.each do |i|
+      interactions.delete_if do |i|
         VCR::Config.invoke_hook(type, tag, i, self)
+        i.ignored?
       end
     end
   end

lib/vcr/structs.rb

@@ -157,5 +157,13 @@ def self.from_net_http_response(response)
   class HTTPInteraction < Struct.new(:request, :response)
     extend ::Forwardable
     def_delegators :request, :uri, :method
+
+    def ignore!
+      @ignored = true
+    end
+
+    def ignored?
+      @ignored
+    end
   end
 end

spec/vcr/cassette_spec.rb

@@ -227,6 +227,16 @@
             cassette.should have(3).recorded_interactions
           end
 
+          it 'does not playback any interactions that are ignored in a before_playback hook' do
+            VCR.config do |c|
+              c.before_playback { |i| i.ignore! if i.request.uri =~ /foo/ }
+            end
+
+            VCR::Config.cassette_library_dir = "#{VCR::SPEC_ROOT}/fixtures/#{YAML_SERIALIZATION_VERSION}/cassette_spec"
+            cassette = VCR::Cassette.new('example', :record => record_mode)
+            cassette.should have(2).recorded_interactions
+          end
+
           it "stubs the recorded requests with the http stubbing adapter" do
             VCR::Config.cassette_library_dir = "#{VCR::SPEC_ROOT}/fixtures/#{YAML_SERIALIZATION_VERSION}/cassette_spec"
             VCR.http_stubbing_adapter.should_receive(:stub_requests).with([an_instance_of(VCR::HTTPInteraction)]*3, anything)
@@ -297,6 +307,31 @@
       cassette.eject
     end
 
+    it 'does not record interactions that have been ignored' do
+      interaction_1 = VCR::HTTPInteraction.new(:request_1, :response_1)
+      interaction_2 = VCR::HTTPInteraction.new(:request_2, :response_2)
+
+      interaction_1.ignore!
+
+      cassette = VCR::Cassette.new('test_cassette')
+      cassette.stub!(:new_recorded_interactions).and_return([interaction_1, interaction_2])
+      cassette.eject
+
+      saved_recorded_interactions = YAML.load_file(cassette.file)
+      saved_recorded_interactions.should == [interaction_2]
+    end
+
+    it 'does not write the cassette to disk if all interactions have been ignored' do
+      interaction_1 = VCR::HTTPInteraction.new(:request_1, :response_1)
+      interaction_1.ignore!
+
+      cassette = VCR::Cassette.new('test_cassette')
+      cassette.stub!(:new_recorded_interactions).and_return([interaction_1])
+      cassette.eject
+
+      File.should_not exist(cassette.file)
+    end
+
     it "writes the recorded interactions to a subdirectory if the cassette name includes a directory" do
       recorded_interactions = [VCR::HTTPInteraction.new(:the_request, :the_response)]
       cassette = VCR::Cassette.new('subdirectory/test_cassette')

spec/vcr/structs_spec.rb

@@ -173,4 +173,15 @@ def instance(body)
       instance.send(attr).should == :the_value
     end
   end
+
+  describe '#ignored?' do
+    it 'returns false by default' do
+      should_not be_ignored
+    end
+
+    it 'returns true when #ignore! has been called' do
+      subject.ignore!
+      should be_ignored
+    end
+  end
 end