ZOak

A Deno Library: Zod + Oak + Openapi3.0

• Validate Inputs
  • Query
  • Path parameters
  • Body
• Validate Responses
• Write handler functions with typed in- and output
• Generate openapi specs from your code

Usage

// Create a new app
api = new ZOak();
// Oak app available: api.oakApp

// Create a router to group endpoints
// extends Oak Router
router = new EndpointRouter();

// define endpoints, see examples below
router.endpoint(...);
router.endpoint(...);

// register router(s)
api.addRouter(router);

// start server
await api.listen(8080)

Examples

Basic with path parameter

router.endpoint(
  "/hello/:name",
  // Method
  "get",
  {
    // Define inputs
    params: z.object({
      name: z.string(),
    }),
    /* Define query
    query: z.object({
        foo: z.string(),
        bar: z.coerce.number()
    })
    */
    // Define responses
    responses: {
      200: z.object({
        hello: z.string(),
      }),
    },
  },
  // Handler receives inputs based on schema(s) defined
  // and Oak's ctx as a second parameter
  async (inputs, ctx) => {
    // Return response as tuple
    return [200, { hello: inputs.params.name }];
  },
);

Advanced with complex validation

router.endpoint(
  "/authors",
  "post",
  {
    body: z.object({
      // Use zod for advanced runtime validation
      name: z.string().max(10),
      age: z.number().min(18).max(99),
      favoriteColor: z.string().optional(),
    }),
    responses: {
      201: z.object({
        id: z.string(),
        name: z.string(),
        age: z.number(),
        favoriteColor: z.string().nullable(),
      }),
    },
  },
  async (inputs, ctx) => {
    // await yourAsyncOperation(inputs.body)
    return [201, { id: "123", favoriteColor: null, ...inputs.body }];
  },
);

Generate OpenApi 3 Json

// generate a json document
const document: string = api.openapi3({ title: "My Api", version: "1.0.0" });

The generated Document is does not specify reference objects, but does a good job of quickly providing an overview of your api including inputs and responses.

Error Handling

If input validation (query, path params or body) fails, 400 Invalid Request is returned.

If response validation fails, 500 Internal Server Error is returned

By default, details about the failed validation are returned in the response body.

You may use a custom middleware to control this behaviour, eg:

api.oakApp.use(async (context, next) => {
  try {
    await next();
  } catch (err) {
    if (isHttpError(err)) {
      context.response.status = err.status;
    } else {
      context.response.status = 500;
    }
    context.response.body = { error: err.message };
    context.response.type = "json";
  }
});

Tests

deno test --allow-net