feat: add endpoints to get latest pacticipant version and latest tagg…

…ed version

lib/pact_broker/api.rb

@@ -44,6 +44,8 @@ module PactBroker
         add ['pacticipants', :name], Api::Resources::Pacticipant, {resource_name: "pacticipant"}
         add ['pacticipants', :pacticipant_name, 'versions'], Api::Resources::Versions, {resource_name: "pacticipant_versions"}
         add ['pacticipants', :pacticipant_name, 'versions', :pacticipant_version_number], Api::Resources::Version, {resource_name: "pacticipant_version"}
+        add ['pacticipants', :pacticipant_name, 'versions', 'latest', :tag], Api::Resources::Version, {resource_name: "latest_tagged_pacticipant_version"}
+        add ['pacticipants', :pacticipant_name, 'versions', 'latest'], Api::Resources::Version, {resource_name: "latest_pacticipant_version"}
         add ['pacticipants', :pacticipant_name, 'versions', :pacticipant_version_number, 'tags', :tag_name], Api::Resources::Tag, {resource_name: "pacticipant_version_tag"}
         add ['pacticipants', :pacticipant_name, 'labels', :label_name], Api::Resources::Label, {resource_name: "pacticipant_label"}
 

lib/pact_broker/api/resources/index.rb

@@ -50,11 +50,20 @@ def to_json
               'pb:latest-provider-pacts-with-tag' =>
               {
                 href: base_url + '/pacts/provider/{provider}/latest/{tag}',
-                title: 'Latest pacts by provider with a specified tag',
+                title: 'Latest pacts by provider with the specified tag',
                 templated: true
               },
-              'pb:webhooks' =>
-              {
+              'pb:latest-version' => {
+                href: base_url + '/pacticipants/{pacticipant}/versions/latest',
+                title: 'Latest pacticipant version',
+                templated: true
+              },
+              'pb:latest-tagged-version' => {
+                href: base_url + '/pacticipants/{pacticipant}/versions/latest/{tag}',
+                title: 'Latest pacticipant version with the specified tag',
+                templated: true
+              },
+              'pb:webhooks' => {
                 href: base_url + '/webhooks',
                 title: 'Webhooks',
                 templated: false

lib/pact_broker/api/resources/version.rb

@@ -32,11 +32,15 @@ def delete_resource
         private
 
         def version
-          @version ||= version_service.find_by_pacticipant_name_and_number path_info
+          if path_info[:tag]
+            @version ||= version_service.find_by_pacticpant_name_and_latest_tag(path_info[:pacticipant_name], path_info[:tag])
+          elsif path_info[:number]
+            @version ||= version_service.find_by_pacticipant_name_and_number path_info
+          else
+            @version ||= version_service.find_latest_by_pacticpant_name path_info
+          end
         end
-
       end
     end
-
   end
 end

lib/pact_broker/versions/service.rb

@@ -7,6 +7,10 @@ class Service
 
       extend PactBroker::Repositories
 
+      def self.find_latest_by_pacticpant_name params
+        version_repository.find_latest_by_pacticpant_name params.fetch(:pacticipant_name)
+      end
+
       def self.find_by_pacticipant_name_and_number params
         version_repository.find_by_pacticipant_name_and_number params.fetch(:pacticipant_name), params.fetch(:pacticipant_version_number)
       end

spec/service_consumers/hal_relation_proxy_app.rb

@@ -0,0 +1,36 @@
+class HalRelationProxyApp
+
+  # This hash allows us to do a dodgy "generators" implementation
+  # It means we can use placeholder URLS for the relations in our consumer tests so that
+  # the consumer does not need to know the actual URLs.
+  PATH_REPLACEMENTS = {
+    '/HAL-REL-PLACEHOLDER-INDEX-PB-LATEST-TAGGED-VERSION-Condor-production' =>
+      '/pacticipants/Condor/versions/latest/production',
+    '/HAL-REL-PLACEHOLDER-INDEX-PB-LATEST-VERSION-Condor' =>
+      '/pacticipants/Condor/versions/latest'
+  }
+
+  RESPONSE_BODY_REPLACEMENTS = {
+  }
+
+  def initialize(app)
+    @app = app
+  end
+
+  def call env
+    env_with_modified_path = env
+    PATH_REPLACEMENTS.each do | (find, replace) |
+      env_with_modified_path['PATH_INFO'] = env_with_modified_path['PATH_INFO'].gsub(find, replace)
+    end
+
+    response = @app.call(env_with_modified_path)
+
+    modified_response_body = response.last.join
+    RESPONSE_BODY_REPLACEMENTS.each do | (find, replace) |
+      modified_response_body = modified_response_body.gsub(find, replace)
+    end
+
+    [response[0], response[1], [modified_response_body]]
+  end
+
+end

spec/service_consumers/pact_helper.rb

@@ -6,12 +6,32 @@
 PactBroker::DB.connection = PactBroker::Database.database = DB::PACT_BROKER_DB
 
 require 'spec/support/database_cleaner'
-require 'pact_broker/api'
+require 'pact_broker'
+require 'pact_broker/app'
 
+require_relative 'hal_relation_proxy_app'
 require_relative 'provider_states_for_pact_broker_client'
 
+pact_broker = PactBroker::App.new { |c| c.database_connection = DB::PACT_BROKER_DB }
+app_to_verify = HalRelationProxyApp.new(pact_broker)
+
+module Rack
+  module PactBroker
+    class DatabaseTransaction
+      def do_not_rollback? response
+        # Dodgey hack to stop exceptions raising a Rollback error while verifying
+        # Otherwise the provider states that deliberately raise exceptions
+        # end up raising exceptions that break the verification tests
+        true
+      end
+    end
+  end
+end
+
 Pact.service_provider "Pact Broker" do
 
+  app { HalRelationProxyApp.new(app_to_verify) }
+
   honours_pact_with "Pact Broker Client" do
     pact_uri "https://raw.githubusercontent.com/pact-foundation/pact_broker-client/master/spec/pacts/pact_broker_client-pact_broker.json"
   end

spec/service_consumers/provider_states_for_pact_broker_client.rb

@@ -2,6 +2,33 @@
 
 Pact.provider_states_for "Pact Broker Client" do
 
+  provider_state "the pb:latest-tagged-version relation exists in the index resource" do
+    no_op
+  end
+
+  provider_state "'Condor' exists in the pact-broker with the latest tagged 'production' version 1.2.3" do
+    set_up do
+      TestDataBuilder.new
+        .create_consumer("Condor")
+        .create_consumer_version("1.2.3")
+        .create_consumer_version_tag("production")
+        .create_consumer_version("2.0.0")
+    end
+  end
+
+  provider_state "the pb:latest-version relation exists in the index resource" do
+    no_op
+  end
+
+  provider_state "'Condor' exists in the pact-broker with the latest version 1.2.3" do
+    set_up do
+      TestDataBuilder.new
+        .create_consumer("Condor")
+        .create_consumer_version("1.0.0")
+        .create_consumer_version("1.2.3")
+    end
+  end
+
   provider_state "the pact for Foo Thing version 1.2.3 has been verified by Bar version 4.5.6" do
     set_up do
       TestDataBuilder.new