feat(zod-openapi): implement Zod schema validation on response

.changeset/itchy-games-fail.md

@@ -0,0 +1,5 @@
+---
+'@hono/zod-openapi': minor
+---
+
+add response Zod schema validation on response

packages/zod-openapi/src/index.ts

@@ -153,6 +153,8 @@ type HandlerResponse<O> = TypedResponse<O> | Promise<TypedResponse<O>>
 
 export type OpenAPIHonoOptions<E extends Env> = {
  defaultHook?: Hook<any, E, any, any>
+ strictStatusCode?: boolean
+ strictResponse?: boolean
 }
 type HonoInit<E extends Env> = ConstructorParameters<typeof Hono>[0] & OpenAPIHonoOptions<E>
 
@@ -187,11 +189,15 @@ export class OpenAPIHono<
 > extends Hono<E, S, BasePath> {
  openAPIRegistry: OpenAPIRegistry
  defaultHook?: OpenAPIHonoOptions<E>['defaultHook']
+ strictStatusCode?: OpenAPIHonoOptions<E>['strictStatusCode']
+ strictResponse?: OpenAPIHonoOptions<E>['strictResponse']
 
  constructor(init?: HonoInit<E>) {
  super(init)
  this.openAPIRegistry = new OpenAPIRegistry()
  this.defaultHook = init?.defaultHook
+ this.strictStatusCode = init?.strictStatusCode
+ this.strictResponse = init?.strictResponse
  }
 
  openapi = <
@@ -256,6 +262,55 @@ export class OpenAPIHono<
  }
  }
 
+ if (this.strictResponse) {
+ const responseZodSchemaObject: Record<string, ZodType<any>> = {}
+ for (const [statusCode, responseConfig] of Object.entries(route.responses)) {
+ for (const mediaTypeObject of Object.values(responseConfig.content ?? {})) {
+ if (mediaTypeObject.schema instanceof ZodType) {
+ responseZodSchemaObject[statusCode] = mediaTypeObject.schema
+ }
+ }
+ }
+
+ if (Object.keys(responseZodSchemaObject).length > 0) {
+ validators.push(async (c, next) => {
+ await next()
+
+ const schema = responseZodSchemaObject[c.res.status]
+ if (schema) {
+ const originalBody = await c.res.json()
+ const result = await schema.safeParseAsync(originalBody)
+ if (!result.success) {
+ c.res = c.json(result.error, {
+ status: 500,
+ })
+ } else {
+ c.res = c.json(result.data)
+ }
+ }
+ })
+ }
+ }
+
+ if (this.strictStatusCode) {
+ validators.push(async (c, next) => {
+ await next()
+
+ if (!route.responses[c.res.status]) {
+ c.res = c.json(
+ {
+ success: false,
+ error: 'Response code does not match any of the defined responses.',
+ },
+ {
+ status: 500,
+ }
+ )
+ return
+ }
+ })
+ }
+
  this.on([route.method], route.path.replaceAll(/\/{(.+?)}/g, '/:$1'), ...validators, handler)
  return this
  }