Change response types to ensure proper status and headers are set

Author: luqasn

packages/cli/src/typegen/templates.ts

@@ -17,12 +17,25 @@ export type Property<T, K extends keyof any, D = unknown> =
 export type ValueOf<T, D = never> = T extends Record<string, unknown> ? T[keyof T] : D;
 
 export type EmptyObject = Record<never, never>;
+
+export type StatusCode<Status> =
+    Status extends '4XX' ? FourXX :
+        Status extends '5XX' ? FiveXX :
+            Status extends number ? Status :
+                Status extends \`\${infer N extends number}\` ? N :
+                    never;
+
+export type FourXX = 400 | 401 | 402 | 403 | 404 | 405 | 406 | 407 | 408 | 409 |
+    410 | 411 | 412 | 413 | 414 | 415 | 416 | 417 | 418 | 421 |
+    422 | 423 | 424 | 425 | 426 | 428 | 429 | 431 | 451;
+
+export type FiveXX = 500 | 501 | 502 | 503 | 504 | 505 | 506 | 507 | 508 | 510 | 511;
 `;
 
 export const requests = `
-import {Params, Request, Response} from '@openapi-ts/request-types';
+import {Params, Request} from '@openapi-ts/request-types';
 import {operations} from './spec';
-import {EmptyObject, Property, ValueOf} from './utils';
+import {EmptyObject, Property, ValueOf, StatusCode} from './utils';
 
 export type RequestBody<OperationId extends keyof operations> =
     operations[OperationId] extends {requestBody: Record<string, any>} ?
@@ -38,8 +51,23 @@ export type RequestQuery<OperationId extends keyof operations> =
 export type RequestHeaders<OperationId extends keyof operations> =
     Property<Property<operations[OperationId], 'parameters', EmptyObject>, 'header', EmptyObject>;
 
-export type ResponseBody<OperationId extends keyof operations> =
-    ValueOf<Property<ValueOf<Property<operations[OperationId], 'responses', EmptyObject>>, 'content'>, void>;
+export type OperationResponse<OpName extends keyof operations> = {
+    [Status in keyof operations[OpName]['responses']]:
+    operations[OpName]['responses'][Status] extends {
+            content: infer Content;
+        }
+        ? {
+            [CT in keyof Content]: {
+                statusCode: StatusCode<Status>;
+                headers: { 'Content-Type': CT };
+                body: Content[CT];
+            }
+        }[keyof Content]
+        : {
+            statusCode: StatusCode<Status>;
+            headers: EmptyObject;
+        };
+}[keyof operations[OpName]['responses']]
 
 export type ResponseHeaders<OperationId extends keyof operations> =
     Property<ValueOf<Property<operations[OperationId], 'responses', EmptyObject>>, 'headers'>;
@@ -49,10 +77,6 @@ export type OperationRequest<OperationId extends keyof operations> = Request<
     Params & RequestPathParams<OperationId>,
     Params & RequestQuery<OperationId>,
     Params & RequestHeaders<OperationId>>;
-
-export type OperationResponse<OperationId extends keyof operations> = Response<
-    ResponseBody<OperationId>,
-    Params & ResponseHeaders<OperationId>>;
 `;
 
 export const handlers = `

packages/lib/src/index.ts

@@ -1,3 +1,4 @@
 export * from './types';
 export * from './errors';
 export * from './openapi';
+export * from './response';

packages/lib/src/openapi.ts

@@ -254,8 +254,10 @@ export class OpenApi<T> {
 
       // Note: The handler function may modify the "res" object and/or return a response body.
       // If "res.body" is undefined we use the return value as the body.
-      const resBody = await operationHandler(req, res, operationParams);
-      res.body = res.body ?? resBody;
+      const returnedResponse = await operationHandler(req, res, operationParams);
+      if (returnedResponse !== undefined) {
+        Object.assign(res, returnedResponse);
+      }
 
       // If status code is not specified and a non-ambiguous default status code is available, use it
       res.statusCode = res.statusCode ?? this.getDefaultStatusCode(operation);

packages/lib/src/response.ts

@@ -0,0 +1,16 @@
+export function json<T>(body: T): { statusCode: 200; body: T; headers: { "Content-Type": "application/json" } };
+export function json<T, CT extends number>(body: T, status: CT): { statusCode: CT; body: T; headers: { "Content-Type": "application/json" } };
+
+export function json<T, CT extends number = 200>(
+    body: T,
+    status?: CT
+): {statusCode: CT | 200; body: T; headers: { "Content-Type": "application/json" } } {
+    const statusCode = status ?? 200
+    return {
+        statusCode,
+        body,
+        headers: {
+            "Content-Type": "application/json",
+        },
+    }
+}

packages/lib/src/types.ts

@@ -103,9 +103,8 @@ export type RequestHandler<P = unknown,
     Req extends Request = Request,
     Res extends Response = Response> = (
         req: Req,
-        res: Res,
-        params: P) => Awaitable<Res['body'] | void>;
-
+        res: Response,
+        params: P) => Awaitable<Res | void>;
 
 type SecuritySchemeObject = OpenAPIV3_1.SecuritySchemeObject | OpenAPIV3.SecuritySchemeObject;
 /**

packages/test/api.yml

@@ -152,6 +152,37 @@ paths:
               schema:
                 type: object
                 additionalProperties: true
+  '/multiresponse':
+    get:
+      operationId: multiResponse
+      summary: test multiple possible responses
+      parameters:
+        - in: query
+          name: type
+          schema:
+            type: string
+
+      responses:
+        '200':
+          description: OK
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  okBody:
+                    type: number
+            text/html:
+              schema:
+                type: string
+
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                type: object
+
 
 
 

packages/test/package.json

@@ -2,7 +2,7 @@
   "name": "test",
   "scripts": {
     "pretest": "npm -w ../lib run build && openapi-ts-backend generate-types api.yml src/gen",
-    "test": "LOG_LEVEL=${LOG_LEVEL:=error} jest"
+    "test": "tsc && LOG_LEVEL=${LOG_LEVEL:=error} jest"
   },
   "devDependencies": {
     "@openapi-ts/cli": "*",

packages/test/src/openapi.test.ts

@@ -1,4 +1,4 @@
-import {HttpError, OpenApi} from "@openapi-ts/backend";
+import {HttpError, json, OpenApi} from "@openapi-ts/backend";
 import { OperationHandlers} from './gen';
 
 function greet(title: string, name: string): string {
@@ -13,23 +13,43 @@ const operations: OperationHandlers<unknown> = {
   greet: req => {
     const {params: {name}, query: {title = ''}} = req;
 
-    return {
-      message: greet(title, name),
-    };
+    return json({ message: greet(title, name)})
   },
   addPerson: req => {
-    return req.body.person;
+    return json(req.body.person, 201);
   },
   getTypes: req => {
-    return {
+    return json({
       params: getTypeMap(req.params),
       headers: getTypeMap(req.headers),
       query: getTypeMap(req.query),
       cookies: getTypeMap(req.cookies),
-    }
+    })
   },
   deletePerson: () => {
     return;
+  },
+  multiResponse: (req) => {
+    if (req.query.type === '') {
+        return {
+            statusCode: 404,
+            body: {},
+            headers: {
+                'Content-Type': 'application/json',
+                'Additional-Header': 'somethingelse'
+            }
+        }
+    }
+    if (req.query.type === 'html') {
+        return {
+            statusCode: 200,
+            body: 'htmlContent',
+            headers: {
+                'Content-Type': 'text/html'
+            }
+        }
+    }
+    return json({ okBody: 1337 })
   }
 };
 

packages/test/tsconfig.json

@@ -2,6 +2,7 @@
   "extends": "../../tsconfig.json",
   "compilerOptions": {
     "rootDir": "./src",
-    "noEmit": true,
+    "noEmit": true
   },
+  "exclude": ["jest.config.ts"]
 }