Add a macro for complexes multiparts

This will allow to describe multipart in a short way, like JSON payload:

Before:

    put 'Creates a blog with thumbnail' do
      consumes 'multipart/form-data'
      parameter name: :title, in: :formData, type: :string, required: true
      parameter name: :content, in: :formData, type: :string, required: true
      parameter name: :file, in: :formData, type: :file, required: true

      let(:blog) { FactoryBot.build(:blog) }
      let(:title) { blog.title }
      let(:content) { blog.content }
      let(:file) { blog.file }

      ...
    end

After:

    put 'Creates a blog with thumbnail' do
      consumes 'multipart/form-data'
      parameter name: :blog, in: :formData, schema: { '$ref' => '#/definitions/blog' }

      let(:blog) { FactoryBot.attributes_for(:blog) }

      ...
    end

Your mileage may vary but you can always choose the best option.

rswag-specs/lib/rswag/specs/request_factory.rb

@@ -185,8 +185,22 @@ module Rswag
         # Rather that serializing with the appropriate encoding (e.g. multipart/form-data),
         # Rails test infrastructure allows us to send the values directly as a hash
         # PROS: simple to implement, CONS: serialization/deserialization is bypassed in test
+        smart_payload = build_smart_form_payload(parameters, example)
+        raw_payload = build_raw_form_payload(parameters, example)
+
+        smart_payload.merge(raw_payload)
+      end
+
+      def build_smart_form_payload(parameters, example)
+        smart_tuples = parameters
+          .select { |p| p[:in] == :formData && p[:schema] }
+          .map { |p| example.send(p[:name]) }
+          .reduce({}, :merge)
+      end
+
+      def build_raw_form_payload(parameters, example)
         tuples = parameters
-          .select { |p| p[:in] == :formData }
+          .select { |p| p[:in] == :formData && !p[:schema] }
           .map { |p| [p[:name], example.send(p[:name])] }
         Hash[tuples]
       end

rswag-specs/spec/rswag/specs/request_factory_spec.rb

@@ -178,6 +178,20 @@ module Rswag
               )
             end
           end
+
+          context 'smart form payload' do
+            before do
+              metadata[:operation][:consumes] = ['multipart/form-data']
+              metadata[:operation][:parameters] = [{ name: 'comment', in: :formData, schema: { type: 'object' } }]
+              allow(example).to receive(:comment).and_return(text: 'Some comment')
+            end
+
+            it 'sets payload to hash of names and example values' do
+              expect(request[:payload]).to eq(
+                :text => 'Some comment'
+              )
+            end
+          end
         end
 
         context 'produces content' do

test-app/app/controllers/blogs_controller.rb

@@ -8,6 +8,12 @@ class BlogsController < ApplicationController
     respond_with @blog
   end
 
+  # POST /blogs/multipart
+  def multipart_create
+    @blog = Blog.create(params.require(:blog).permit(:title, :content))
+    respond_with @blog
+  end
+
   # POST /blogs/flexible
   def flexible_create
 

test-app/config/routes.rb

@@ -1,5 +1,6 @@
 TestApp::Application.routes.draw do
 
+  post '/blogs/multipart', to: 'blogs#multipart_create'
   post '/blogs/flexible', to: 'blogs#flexible_create'
   post '/blogs/alternate', to: 'blogs#alternate_create'
   resources :blogs

test-app/spec/features/swagger_ui_spec.rb

@@ -7,6 +7,7 @@ RSpec.feature 'swagger-ui', js: true do
 
     expect(page).to have_content('GET /blogs Searches blogs', normalize_ws: true)
     expect(page).to have_content('POST /blogs Creates a blog', normalize_ws: true)
+    expect(page).to have_content('POST /blogs/multipart Creates a blog using multipart', normalize_ws: true)
     expect(page).to have_content('GET /blogs/{id} Retrieves a blog', normalize_ws: true)
   end
 end

test-app/spec/integration/blogs_spec.rb

@@ -49,6 +49,33 @@ RSpec.describe 'Blogs API', type: :request, swagger_doc: 'v1/swagger.json' do
     end
   end
 
+  path '/blogs/multipart' do
+    post 'Creates a blog using multipart' do
+      tags 'Blogs'
+      description 'Creates a new blog from provided data'
+      operationId 'createBlogWithMultipart'
+      consumes 'multipart/form-data'
+      produces 'application/json'
+      parameter name: :blog, in: :formData, schema: { type: :object, properties: { name: :blog, type: :object, properties: { '$ref' => '#/definitions/blog' } } }
+
+      let(:blog) { { blog: { title: 'foo', content: 'bar' } } }
+
+      response '201', 'blog created' do
+        # schema '$ref' => '#/definitions/blog'
+        run_test!
+      end
+
+      response '422', 'invalid request' do
+        schema '$ref' => '#/definitions/errors_object'
+
+        let(:blog) { { blog: { title: 'foo' } } }
+        run_test! do |response|
+          expect(response.body).to include("can't be blank")
+        end
+      end
+    end
+  end
+
   path '/blogs/flexible' do
     post 'Creates a blog flexible body' do
       tags 'Blogs'

test-app/swagger/v1/swagger.json

@@ -155,6 +155,52 @@
         }
       }
     },
+    "/blogs/multipart": {
+      "post": {
+        "summary": "Creates a blog using multipart",
+        "tags": [
+          "Blogs"
+        ],
+        "description": "Creates a new blog from provided data",
+        "operationId": "createBlogWithMultipart",
+        "parameters": [
+
+        ],
+        "responses": {
+          "201": {
+            "description": "blog created",
+            "content": {
+            }
+          },
+          "422": {
+            "description": "invalid request",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/definitions/errors_object"
+                }
+              }
+            }
+          }
+        },
+        "requestBody": {
+          "content": {
+            "multipart/form-data": {
+              "schema": {
+                "type": "object",
+                "properties": {
+                  "name": "blog",
+                  "type": "object",
+                  "properties": {
+                    "$ref": "#/definitions/blog"
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    },
     "/blogs/flexible": {
       "post": {
         "summary": "Creates a blog flexible body",