Add WebMock.globally_stub_request.

This allows easier integration with WebMock by another library like VCR so it can register a global hook to handle every request.

lib/webmock/stub_registry.rb

@@ -4,13 +4,30 @@ class StubRegistry
     include Singleton
 
     attr_accessor :request_stubs
+    attr_accessor :global_stub
 
     def initialize
       reset!
     end
 
     def reset!
-      self.request_stubs = []
+      self.request_stubs = global_stub ? [global_stub] : []
+    end
+
+    def global_stub_block=(block)
+      self.global_stub = ::WebMock::RequestStub.new(:any, /.*/)
+
+      # This hash contains the responses returned by the block,
+      # keyed by the exact request (using the object_id).
+      # That way, there's no race condition in case #to_return
+      # doesn't run immediately after stub.with.
+      responses = {}
+
+      self.global_stub.with { |request|
+        responses[request.object_id] = block.call(request)
+      }.to_return(lambda { |request| responses.delete(request.object_id) })
+
+      register_request_stub(self.global_stub)
     end
 
     def register_request_stub(stub)

lib/webmock/webmock.rb

@@ -88,6 +88,10 @@ def self.print_executed_requests
     puts WebMock::RequestExecutionVerifier.executed_requests_message
   end
 
+  def self.globally_stub_request(&block)
+    WebMock::StubRegistry.instance.global_stub_block = block
+  end
+
   %w(
     allow_net_connect!
     disable_net_connect!

spec/acceptance/shared/stubbing_requests.rb

@@ -287,6 +287,56 @@
       end
     end
 
+    describe "when stubbing request with a global hook" do
+      after(:each) do
+        WebMock::StubRegistry.instance.global_stub = nil
+      end
+
+      it 'returns the response returned by the hook' do
+        WebMock.globally_stub_request do |request|
+          { :body => "global stub body" }
+        end
+
+        http_request(:get, "http://www.example.com/").body.should == "global stub body"
+      end
+
+      it 'does not get cleared when a user calls WebMock.reset!' do
+        WebMock.globally_stub_request do |request|
+          { :body => "global stub body" }
+        end
+        WebMock.reset!
+        http_request(:get, "http://www.example.com/").body.should == "global stub body"
+      end
+
+      it "does not stub the request if the hook does not return anything" do
+        WebMock.globally_stub_request { |r| }
+        lambda {
+          http_request(:get, "http://www.example.com/")
+        }.should raise_error(WebMock::NetConnectNotAllowedError, %r(Real HTTP connections are disabled. Unregistered request: GET http://www.example.com/))
+      end
+
+      it "passes the request to the block" do
+        passed_request = nil
+        WebMock.globally_stub_request do |request|
+          passed_request = request
+          { :body => "global stub body" }
+        end
+
+        http_request(:get, "http://www.example.com:456/bar")
+        passed_request.uri.to_s.should == "http://www.example.com:456/bar"
+      end
+
+      it "should call the block only once per request" do
+        call_count = 0
+        WebMock.globally_stub_request do |request|
+          call_count += 1
+          { :body => "global stub body" }
+        end
+        http_request(:get, "http://www.example.com/")
+        call_count.should == 1
+      end
+    end
+
     describe "when stubbing request with a block evaluated on request" do
       it "should match if block returns true" do
         stub_request(:get, "www.example.com").with { |request| true }