Add #select_example_response config option.

seomoz · Oct 18, 2012 · c9c1fd5 · c9c1fd5
1 parent 1ca7799
commit c9c1fd5
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Showing 6 changed files with 125 additions and 36 deletions.
diff --git a/README.md b/README.md
@@ -231,6 +231,21 @@ Interpol.default_configuration do |config|
     example.data["current_url"] = Rack::Request.new(request_env).url
   end
 
+  # Sets a callback that will be used to determine which example
+  # to return from the stub app. If you provide an endpoint name,
+  # the block will apply only to requests to that endpoint.
+  # If no name is provided, the block will set the default selector
+  # logic. By default, if this config is not set, interpol will use
+  # the first example.
+  #
+  # Used by Interpol::StubApp.
+  config.select_example_response('some-endpoint') do |endpoint_def, request_env|
+    endpoint_def.examples[3]
+  end
+  config.select_example_response do |endpoint_def, request_env|
+    endpoint_def.examples.first
+  end
+
   # Determines what to do when Interpol::Sinatra::RequestParamsParser
   # detects invalid path or query parameters based on their schema
   # definitions. This block will be eval'd in the context of your

diff --git a/lib/interpol/configuration.rb b/lib/interpol/configuration.rb
@@ -141,6 +141,19 @@ def filter_example_data(&block)
       filter_example_data_blocks << block
     end
 
+    def select_example_response(endpoint_name = nil, &block)
+      if endpoint_name
+        named_example_selectors[endpoint_name] = block
+      else
+        named_example_selectors.default = block
+      end
+    end
+
+    def example_response_for(endpoint_def, env)
+      selector = named_example_selectors[endpoint_def.endpoint_name]
+      selector.call(endpoint_def, env)
+    end
+
     def self.default
       @default ||= Configuration.new
     end
@@ -187,6 +200,10 @@ def rack_json_response(status, hash)
                  'Content-Length' => json.bytesize }, [json]]
     end
 
+    def named_example_selectors
+      @named_example_selectors ||= {}
+    end
+
     def register_default_callbacks
       request_version do
         raise ConfigurationError, "request_version has not been configured"
@@ -229,6 +246,10 @@ def register_default_callbacks
       on_invalid_sinatra_request_params do |error|
         halt 400, JSON.dump(:error => error.message)
       end
+
+      select_example_response do |endpoint_def, _|
+        endpoint_def.examples.first
+      end
     end
   end
 end

diff --git a/lib/interpol/endpoint.rb b/lib/interpol/endpoint.rb
@@ -68,14 +68,6 @@ def find_definitions(version, message_type, &block)
       @definitions_hash.fetch([message_type, version], &block)
     end
 
-    def find_example_for!(version, message_type)
-      find_definition!(version, message_type).examples.first
-    end
-
-    def find_example_status_code_for!(version)
-      find_definition!(version, 'response').example_status_code
-    end
-
     def available_request_versions
       available_versions_matching &:request?
     end

diff --git a/lib/interpol/stub_app.rb b/lib/interpol/stub_app.rb
@@ -44,24 +44,25 @@ def build
 
       def endpoint_definition(endpoint)
         lambda do
-          example, version = settings.
+          endpoint_def = settings.stub_app_builder.endpoint_def_for(endpoint, self)
-                             stub_app_builder.
+          example = settings.stub_app_builder.example_for(endpoint_def, self)
-                             example_and_version_for(endpoint, self)
           example.validate! if settings.perform_validations?
-          status endpoint.find_example_status_code_for!(version)
+          status endpoint_def.example_status_code
           JSON.dump(example.data)
         end
       end
 
-      def example_and_version_for(endpoint, app)
+      def endpoint_def_for(endpoint, app)
         version = config.response_version_for(app.request.env, endpoint)
-        example = endpoint.find_example_for!(version, 'response')
+        endpoint_def = endpoint.find_definition!(version, 'response')
       rescue NoEndpointDefinitionFoundError
-        config.sinatra_request_version_unavailable(app, version,
+        config.sinatra_request_version_unavailable \
-                                                   endpoint.available_response_versions)
+          app, version, endpoint.available_response_versions
-      else
+      end
-        example = example.apply_filters(config.filter_example_data_blocks, app.request.env)
+
-        return example, version
+      def example_for(endpoint_def, app)
+        example = config.example_response_for(endpoint_def, app.request.env)
+        example.apply_filters(config.filter_example_data_blocks, app.request.env)
       end
     end
   end

diff --git a/spec/unit/interpol/endpoint_spec.rb b/spec/unit/interpol/endpoint_spec.rb
@@ -120,21 +120,6 @@ def build_hash(hash = {})
       end
     end
 
-    describe "#find_example_for!" do
-      let(:hash) { build_hash('definitions' => definitions_array) }
-      let(:endpoint) { Endpoint.new(hash) }
-
-      it 'returns an example for the requested version' do
-        endpoint.find_example_for!('1.2', 'response').data.should eq('e1')
-      end
-
-      it 'raises an error when given a version it does not have' do
-        expect {
-          endpoint.find_example_for!('2.1', 'response')
-        }.to raise_error(NoEndpointDefinitionFoundError)
-      end
-    end
-
     describe '#route_matches?' do
       def endpoint(route)
         hash = build_hash('route' => route)

diff --git a/spec/unit/interpol/stub_app_spec.rb b/spec/unit/interpol/stub_app_spec.rb
@@ -36,10 +36,35 @@ module Interpol
       EOF
     end
 
+    let_without_indentation(:another_definition_yml) do <<-EOF
+      ---
+      name: another_endpoint
+      route: /another-endpoint
+      method: GET
+      definitions:
+        - versions: ["1.0"]
+          status_codes: ['200']
+          message_type: response
+          schema:
+            type: object
+            properties:
+              example_num: { type: integer }
+          examples:
+            - example_num: 0
+            - example_num: 1
+        - versions: ["1.0"]
+          message_type: request
+          schema: {}
+          examples: []
+      EOF
+    end
+
     let(:endpoint) { Endpoint.new(YAML.load endpoint_definition_yml) }
+    let(:another_endpoint) { Endpoint.new(YAML.load another_definition_yml) }
+
     let(:default_config) do
       lambda do |config|
-        config.endpoints = [endpoint]
+        config.endpoints = [endpoint, another_endpoint]
 
         unless response_version_configured?(config) # allow default config to take precedence
           config.response_version { |env, _| env.fetch('HTTP_RESPONSE_VERSION') }
@@ -95,6 +120,56 @@ def parsed_body
       last_response.should be_ok
     end
 
+    it 'uses the select_example_response callback to select which example gets returned' do
+      Interpol.default_configuration do |c|
+        c.select_example_response do |endpoint_def, request|
+          endpoint_def.examples.last
+        end
+      end
+
+      header 'Response-Version', '1.0'
+      get '/users/3/projects'
+      parsed_body.should include('name' => 'some other project')
+    end
+
+    it 'can select an example based on the request' do
+      Interpol.default_configuration do |c|
+        c.select_example_response do |endpoint_def, env|
+          index = Integer(env.fetch('HTTP_INDEX'))
+          endpoint_def.examples[index]
+        end
+      end
+
+      header 'Response-Version', '1.0'
+
+      header 'Index', '0'
+      get '/another-endpoint'
+      parsed_body.should include('example_num' => 0)
+
+      header 'Index', '1'
+      get '/another-endpoint'
+      parsed_body.should include('example_num' => 1)
+    end
+
+    it 'can have different example selection logic for a particular endpoint' do
+      Interpol.default_configuration do |c|
+        c.select_example_response do |endpoint_def, request|
+          endpoint_def.examples.last
+        end
+
+        c.select_example_response 'another_endpoint' do |endpoint_def, request|
+          endpoint_def.examples.first
+        end
+      end
+
+      header 'Response-Version', '1.0'
+      get '/users/3/projects'
+      parsed_body.should include('name' => 'some other project')
+
+      get '/another-endpoint'
+      parsed_body.should include('example_num' => 0)
+    end
+
     it 'uses any provided filters to modify the example data' do
       app.settings.stub_app_builder.config.filter_example_data do |example, request_env|
         example.data["name"] += " for #{request_env["REQUEST_METHOD"]}"
@@ -144,7 +219,7 @@ def parsed_body
     end
 
     let(:endpoint_example) do
-      endpoint.find_example_for!('1.0', 'response')
+      endpoint.find_definition!('1.0', 'response').examples.first
     end
 
     it 'performs validations by default' do