Allow requests to be ignored by defining a block.

This is much more flexible than the other config options for ignoring
requests.

Closes vcr#90.

features/configuration/ignore_request.feature

@@ -0,0 +1,186 @@
+Feature: Ignore Request
+
+  By default, VCR hooks into every request, either allowing it and recording
+  it, or playing back a recorded response, or raising an error to force you
+  to deal with the new request.  In some situations, you may prefer to have
+  VCR ignore some requests.
+
+  VCR provides 3 configuration options to accomplish this:
+
+    * `ignore_request { |req| ... }` will ignore any request for which the
+      given block returns true.
+    * `ignore_hosts 'foo.com', 'bar.com'` allows you to specify particular
+      hosts to ignore.
+    * `ignore_localhost = true` is equivalent to `ignore_hosts 'localhost',
+      '127.0.0.1', '0.0.0.0'`. It is particularly useful for when you use
+      VCR with a javascript-enabled capybara driver, since capybara boots
+      your rack app and makes localhost requests to it to check that it has
+      booted.
+
+  Ignored requests are not recorded and are always allowed, regardless of
+  the record mode, and even outside of a `VCR.use_cassette` block.
+
+  Background:
+    Given a file named "sinatra_app.rb" with:
+      """ruby
+      response_count = 0
+      start_sinatra_app(:port => 7777) do
+        get('/') { "Port 7777 Response #{response_count += 1}" }
+      end
+      """
+
+  Scenario Outline: ignore requests to a specific port
+    Given a file named "ignore_request.rb" with:
+      """ruby
+      include_http_adapter_for("<http_lib>")
+      require 'sinatra_app.rb'
+
+      response_count = 0
+      start_sinatra_app(:port => 8888) do
+        get('/') { "Port 8888 Response #{response_count += 1}" }
+      end
+
+      require 'vcr'
+
+      VCR.configure do |c|
+        c.ignore_request do |request|
+          URI(request.uri).port == 7777
+        end
+
+        c.cassette_library_dir = 'cassettes'
+        <configuration>
+      end
+
+      VCR.use_cassette('example') do
+        puts response_body_for(:get, "http://localhost:8888/")
+      end
+
+      VCR.use_cassette('example') do
+        puts response_body_for(:get, "http://localhost:7777/")
+      end
+
+      puts response_body_for(:get, "http://localhost:7777/")
+      puts response_body_for(:get, "http://localhost:8888/")
+      """
+    When I run `ruby ignore_request.rb`
+    Then it should fail with "Real HTTP connections are disabled. Request: GET http://localhost:8888/"
+     And the output should contain:
+      """
+      Port 8888 Response 1
+      Port 7777 Response 1
+      Port 7777 Response 2
+      """
+    And the file "cassettes/example.yml" should contain "body: Port 8888"
+    And the file "cassettes/example.yml" should not contain "body: Port 7777"
+
+    Examples:
+      | configuration         | http_lib              |
+      | c.hook_into :fakeweb  | net/http              |
+      | c.hook_into :webmock  | net/http              |
+      | c.hook_into :typhoeus | typhoeus              |
+      | c.hook_into :excon    | excon                 |
+      | c.hook_into :faraday  | faraday (w/ net_http) |
+
+  Scenario Outline: ignored host requests are not recorded and are always allowed
+    Given a file named "ignore_hosts.rb" with:
+      """ruby
+      include_http_adapter_for("<http_lib>")
+      require 'sinatra_app.rb'
+
+      require 'vcr'
+
+      VCR.configure do |c|
+        c.ignore_hosts '127.0.0.1', 'localhost'
+        c.cassette_library_dir = 'cassettes'
+        <configuration>
+      end
+
+      VCR.use_cassette('example') do
+        puts response_body_for(:get, "http://localhost:7777/")
+      end
+
+      puts response_body_for(:get, "http://localhost:7777/")
+      """
+    When I run `ruby ignore_hosts.rb`
+    Then it should pass with:
+      """
+      Port 7777 Response 1
+      Port 7777 Response 2
+      """
+    And the file "cassettes/example.yml" should not exist
+
+    Examples:
+      | configuration         | http_lib              |
+      | c.hook_into :fakeweb  | net/http              |
+      | c.hook_into :webmock  | net/http              |
+      | c.hook_into :typhoeus | typhoeus              |
+      | c.hook_into :excon    | excon                 |
+      | c.hook_into :faraday  | faraday (w/ net_http) |
+
+  Scenario Outline: localhost requests are not treated differently by default
+    Given a file named "localhost_not_ignored.rb" with:
+      """ruby
+      include_http_adapter_for("<http_lib>")
+      require 'sinatra_app.rb'
+
+      require 'vcr'
+
+      VCR.configure do |c|
+        c.cassette_library_dir = 'cassettes'
+        <configuration>
+      end
+
+      VCR.use_cassette('localhost') do
+        response_body_for(:get, "http://localhost:7777/")
+      end
+
+      response_body_for(:get, "http://localhost:7777/")
+      """
+    When I run `ruby localhost_not_ignored.rb`
+    Then it should fail with "Real HTTP connections are disabled"
+     And the file "cassettes/localhost.yml" should contain "body: Port 7777 Response 1"
+
+    Examples:
+      | configuration         | http_lib              |
+      | c.hook_into :fakeweb  | net/http              |
+      | c.hook_into :webmock  | net/http              |
+      | c.hook_into :typhoeus | typhoeus              |
+      | c.hook_into :excon    | excon                 |
+      | c.hook_into :faraday  | faraday (w/ net_http) |
+
+  Scenario Outline: localhost requests are allowed and not recorded when ignore_localhost = true
+    Given a file named "ignore_localhost_true.rb" with:
+      """ruby
+      include_http_adapter_for("<http_lib>")
+      require 'sinatra_app.rb'
+
+      require 'vcr'
+
+      VCR.configure do |c|
+        c.ignore_localhost = true
+        c.cassette_library_dir = 'cassettes'
+        <configuration>
+      end
+
+      VCR.use_cassette('localhost') do
+        puts response_body_for(:get, "http://localhost:7777/")
+      end
+
+      puts response_body_for(:get, "http://localhost:7777/")
+      """
+    When I run `ruby ignore_localhost_true.rb`
+    Then it should pass with:
+      """
+      Port 7777 Response 1
+      Port 7777 Response 2
+      """
+    And the file "cassettes/localhost.yml" should not exist
+
+    Examples:
+      | configuration         | http_lib              |
+      | c.hook_into :fakeweb  | net/http              |
+      | c.hook_into :webmock  | net/http              |
+      | c.hook_into :typhoeus | typhoeus              |
+      | c.hook_into :excon    | excon                 |
+      | c.hook_into :faraday  | faraday (w/ net_http) |
+

lib/vcr/configuration.rb

@@ -48,6 +48,10 @@ def ignore_localhost=(value)
       VCR.request_ignorer.ignore_localhost = value
     end
 
+    def ignore_request(&block)
+      VCR.request_ignorer.ignore_request(&block)
+    end
+
     attr_writer :allow_http_connections_when_no_cassette
     def allow_http_connections_when_no_cassette?
       !!@allow_http_connections_when_no_cassette

lib/vcr/request_ignorer.rb

@@ -1,10 +1,21 @@
 require 'uri'
 require 'set'
+require 'vcr/util/hooks'
 
 module VCR
   class RequestIgnorer
+    include VCR::Hooks
+
+    define_hook :ignore_request
+
     LOCALHOST_ALIASES = %w( localhost 127.0.0.1 0.0.0.0 )
 
+    def initialize
+      ignore_request do |request|
+        ignored_hosts.include?(URI(request.uri).host)
+      end
+    end
+
     def ignore_localhost=(value)
       if value
         ignore_hosts(*LOCALHOST_ALIASES)
@@ -18,7 +29,8 @@ def ignore_hosts(*hosts)
     end
 
     def ignore?(request)
-      ignored_hosts.include?(URI(request.uri).host)
+      tag = nil # we don't use tags here...
+      invoke_hook(:ignore_request, tag, request).any?
     end
 
   private