feat: rendering the syntax of different content types responses

README.md

@@ -451,6 +451,32 @@ You can decorate your own response headers by following the below example:
 Note: You need to specify `type` property when you decorate the response headers, otherwise the schema will be modified by Fastify.
 
 <a name="route.response.empty_body"></a>
+##### Different content types responses
+**Note:** not supported by Swagger (OpenAPI v2), [only OpenAPI v3](https://swagger.io/docs/specification/describing-responses/)
+<br>
+<br>
+Different content types responses are supported by `@fastify/swagger` and `@fastify`.
+Please use `contentTypes` for the response otherwise Fastify itself will fail to compile the schema:
+
+```js
+{
+  response: {
+    200: {
+      description: 'Description and all status-code based properties are working',
+      contentTypes: [
+        {
+          content: 'application/json',
+          schema: { name: { type: 'string' }, image: { type: 'string' }, address: { type: 'string' } }
+        },
+        {
+          content: 'application/vnd.v1+json',
+          schema: { fullName: { type: 'string' }, phone: { type: 'string' } }
+        }
+      ]
+    }
+  }
+}
+```
 ##### Empty Body Responses
 Empty body responses are supported by `@fastify/swagger`.
 Please specify `type: 'null'` for the response otherwise Fastify itself will fail to compile the schema:

lib/spec/openapi/utils.js

@@ -323,20 +323,28 @@ function resolveResponse (fastifyResponseJson, produces, ref) {
 
     // add schema when type is not 'null'
     if (rawJsonSchema.type !== 'null') {
-      const content = {}
-
-      if ((Array.isArray(produces) && produces.length === 0) || typeof produces === 'undefined') {
-        produces = ['application/json']
-      }
+      if (Array.isArray(resolved.contentTypes)) {
+        const content = {}
+        for (const contnetTypeResponse of resolved.contentTypes) {
+          const media = schemaToMedia(contnetTypeResponse.schema)
+          content[contnetTypeResponse.content] = media
+          response.content = content
+        }
+      } else {
+        const content = {}
 
-      delete resolved[xResponseDescription]
+        if ((Array.isArray(produces) && produces.length === 0) || typeof produces === 'undefined') {
+          produces = ['application/json']
+        }
 
-      const media = schemaToMedia(resolved)
-      produces.forEach((produce) => {
-        content[produce] = media
-      })
+        delete resolved[xResponseDescription]
 
-      response.content = content
+        const media = schemaToMedia(resolved)
+        produces.forEach((produce) => {
+          content[produce] = media
+        })
+        response.content = content
+      }
     }
 
     responsesContainer[statusCode] = response

test/spec/openapi/schema.js

@@ -110,6 +110,61 @@ test('support 2xx response', async t => {
   t.same(definedPath.responses['3XX'].description, 'Default Response')
 })
 
+test('support multiple content types responses', async t => {
+  const fastify = Fastify()
+  await fastify.register(fastifySwagger, {
+    openapi: true,
+    routePrefix: '/docs',
+    exposeRoute: true
+  })
+
+  const opt = {
+    schema: {
+      response: {
+        200: {
+          description: 'Description and all status-code based properties are working',
+          contentTypes: [
+            {
+              content: 'application/json',
+              schema: { name: { type: 'string' }, image: { type: 'string' }, address: { type: 'string' } }
+            },
+            {
+              content: 'application/vnd.v1+json',
+              schema: { fullName: { type: 'string' }, phone: { type: 'string' } }
+            }
+          ]
+        }
+      }
+    }
+  }
+  fastify.get('/', opt, () => {})
+
+  await fastify.ready()
+
+  const swaggerObject = fastify.swagger()
+  const api = await Swagger.validate(swaggerObject)
+  const definedPath = api.paths['/'].get
+  t.same(definedPath.responses['200'].description, 'Description and all status-code based properties are working')
+  t.same(definedPath.responses['200'].content, {
+    'application/json': {
+      schema: {
+        type: 'object',
+        properties: {
+          name: { type: 'string' }, image: { type: 'string' }, address: { type: 'string' }
+        }
+      }
+    },
+    'application/vnd.v1+json': {
+      schema: {
+        type: 'object',
+        properties: {
+          fullName: { type: 'string' }, phone: { type: 'string' }
+        }
+      }
+    }
+  })
+})
+
 test('support status code 204', async t => {
   const opt = {
     schema: {