feat: allow custom rack middleware to be specified

lib/pact/provider_verifier/app.rb

@@ -1,4 +1,6 @@
 require 'pact/provider_verifier/add_header_middlware'
+require 'pact/provider_verifier/provider_states/add_provider_states_header'
+require 'pact/provider_verifier/provider_states/remove_provider_states_header_middleware'
 require 'pact/provider_verifier/custom_middleware'
 require 'pact/provider/rspec'
 require 'pact/message'
@@ -54,16 +56,17 @@ def set_environment_variables
 
       def configure_service_provider
         # Have to declare these locally as the class scope gets lost within the block
-        rack_reverse_proxy = configure_reverse_proxy
-        rack_reverse_proxy = configure_custom_header_middleware(rack_reverse_proxy)
-        rack_reverse_proxy = configure_custom_middlware(rack_reverse_proxy)
+        application = configure_reverse_proxy
+        application = configure_provider_states_header_removal_middleware(application)
+        application = configure_custom_middleware(application)
+        application = configure_custom_header_middleware(application)
 
         provider_application_version = options.provider_app_version
         publish_results  = options.publish_verification_results
 
         Pact.service_provider "Running Provider Application" do
           app do
-            rack_reverse_proxy
+            application
           end
 
           if provider_application_version
@@ -94,7 +97,7 @@ def configure_custom_header_middleware rack_reverse_proxy
         end
       end
 
-      def configure_custom_middlware app
+      def configure_custom_middleware app
         if options.custom_middleware && options.custom_middleware.any?
           require_custom_middlware
           apply_custom_middleware(app)
@@ -103,6 +106,10 @@ def configure_custom_middlware app
         end
       end
 
+      def configure_provider_states_header_removal_middleware app
+        ProviderStates::RemoveProviderStatesHeaderMiddleware.new(app)
+      end
+
       def require_custom_middlware
         options.custom_middleware.each do |file|
           $stdout.puts "DEBUG: Requiring custom middleware file #{file}" if options.verbose
@@ -132,7 +139,8 @@ def verify_pact(config)
             pact_broker_password: options.broker_password,
             format: options.format,
             out: options.out,
-            ignore_failures: config.pending
+            ignore_failures: config.pending,
+            request_customizer: ProviderStates::AddProviderStatesHeader
           }
           verify_options[:description] = ENV['PACT_DESCRIPTION'] if ENV['PACT_DESCRIPTION']
           verify_options[:provider_state] = ENV['PACT_PROVIDER_STATE'] if ENV['PACT_PROVIDER_STATE']
@@ -191,3 +199,5 @@ def print_deprecation_note
     end
   end
 end
+
+

lib/pact/provider_verifier/custom_middleware.rb

@@ -1,3 +1,5 @@
+require 'ostruct'
+
 module Pact
   module ProviderVerifier
     class CustomMiddleware
@@ -18,6 +20,14 @@ def initialize app
       def call env
         raise NotImplementedError
       end
+
+      def provider_states_from(env)
+        if env["X_PACT_PROVIDER_STATES"]
+          env["X_PACT_PROVIDER_STATES"].collect{ | provider_state| OpenStruct.new(provider_state) }
+        else
+          []
+        end
+      end
     end
   end
 end

lib/pact/provider_verifier/provider_states/add_provider_states_header.rb

@@ -0,0 +1,36 @@
+require 'delegate'
+
+module Pact
+  module ProviderVerifier
+    module ProviderStates
+      class RequestDelegate < SimpleDelegator
+        def initialize request, extra_rack_headers
+          super(request)
+          @extra_rack_headers = extra_rack_headers
+        end
+
+        def headers
+          __getobj__().headers.merge(@extra_rack_headers)
+        end
+
+        def method
+          __getobj__().method
+        end
+      end
+
+      class AddProviderStatesHeader
+
+        def self.call(request, interaction)
+          if interaction.provider_state
+            extra_rack_headers = {
+              "X_PACT_PROVIDER_STATES" => [{ "name" => interaction.provider_state }]
+            }
+            RequestDelegate.new(request, extra_rack_headers)
+          else
+            request
+          end
+        end
+      end
+    end
+  end
+end

lib/pact/provider_verifier/provider_states/remove_provider_states_header_middleware.rb

@@ -0,0 +1,19 @@
+module Pact
+  module ProviderVerifier
+    module ProviderStates
+      class RemoveProviderStatesHeaderMiddleware
+        def initialize app
+          @app = app
+        end
+
+        def call env
+          @app.call(remove_header(env))
+        end
+
+        def remove_header env
+          env.reject { | key, value | key == "X_PACT_PROVIDER_STATES" }
+        end
+      end
+    end
+  end
+end

pact-provider-verifier.gemspec

@@ -21,7 +21,7 @@ Gem::Specification.new do |gem|
   gem.license       = 'MIT'
 
   gem.add_runtime_dependency 'rspec', '~> 3.5'
-  gem.add_runtime_dependency 'pact', '~>1.33', '>= 1.33.2'
+  gem.add_runtime_dependency 'pact', '~>1.34'
   gem.add_runtime_dependency 'pact-message', '~>0.4', '>=0.4.1'
   gem.add_runtime_dependency 'faraday', '~> 0.9', '>= 0.9.0'
   gem.add_runtime_dependency 'faraday_middleware', '~> 0.10'

spec/integration_with_custom_middleware_spec.rb

@@ -4,16 +4,20 @@
     sleep 2
   end
 
-  context "with --custom-provider-header specified" do
+  context "with --custom-middleware specified" do
 
-    subject { `bundle exec bin/pact-provider-verifier spec/support/pacts/needs-custom-auth.json --custom-middleware #{Dir.pwd}/spec/support/custom_middleware.rb -a 1.0.100 --provider-base-url http://localhost:4570 2>&1` }
+    subject { `bundle exec bin/pact-provider-verifier spec/support/pacts/needs-custom-auth.json --custom-middleware #{Dir.pwd}/spec/support/custom_middleware.rb -a 1.0.100 --provider-base-url http://localhost:4570 -v 2>&1` }
 
-    it "exits with a 0 exit code" do
+
+    it "can modify the request" do
       subject
-      puts subject
       expect($?).to eq 0
     end
 
+    it "can access the provider state information" do
+      expect(subject).to include "The provider state name is 'custom authorization is required'"
+    end
+
     it "the output contains a success message" do
       expect(subject).to include "0 failures"
     end

spec/lib/pact/provider_verifier/custom_middleware_spec.rb

@@ -5,12 +5,39 @@ module ProviderVerifier
     describe CustomMiddleware do
       describe ".descendants" do
 
-        class TestMiddlware < Pact::ProviderVerifier::CustomMiddleware
+        class TestMiddleware < Pact::ProviderVerifier::CustomMiddleware
 
         end
 
-        it "returns the TestMiddlware" do
-          expect(CustomMiddleware.descendants).to eq [TestMiddlware]
+        it "returns the TestMiddleware" do
+          expect(CustomMiddleware.descendants).to eq [TestMiddleware]
+        end
+      end
+
+      describe "#provider_states_from" do
+
+        subject { CustomMiddleware.new(nil).provider_states_from(env) }
+
+        context "when the X_PACT_PROVIDER_STATES header exists" do
+          let(:env) do
+            {
+              "X_PACT_PROVIDER_STATES" => [{
+                "name" => "foo"
+              }]
+            }
+          end
+
+          it "returns an array of provider states" do
+            expect(subject.first.name).to eq "foo"
+          end
+        end
+
+        context "when the X_PACT_PROVIDER_STATES header does not exist" do
+          let(:env) { {} }
+
+          it "returns an empty array" do
+            expect(subject).to eq []
+          end
         end
       end
     end

spec/support/custom_middleware.rb

@@ -1,11 +1,13 @@
 class AddCustomAuth < Pact::ProviderVerifier::CustomMiddleware
-
   def initialize app
     @app = app
   end
 
   def call env
     env['HTTP_AUTHORIZATION'] = 'Basic cGFjdDpwYWN0'
+    provider_states = provider_states_from(env)
+    provider_state_name = provider_states.any? && provider_states.first.name
+    puts "The provider state name is '#{provider_state_name}'"
     @app.call(env)
   end
 end

spec/support/pacts/needs-custom-auth.json

@@ -7,6 +7,7 @@
   },
   "interactions": [
     {
+      "providerState": "custom authorization is required",
       "description": "a request without any auth header",
       "request": {
         "method": "GET",