OpenAPI 3.1 Validator

This package exposes functionality to validate requests and responses according to a given OpenAPI 3.1 schema.

Installation

You can install the package using:

npm install @interledger/openapi

Usage

Validators

First, instantiate an OpenAPI validator object with a reference to your OpenAPI spec:

const openApi = await createOpenAPI(OPEN_API_URL_OR_FILE_PATH)

Then, validate requests and responses as such:

const validateRequest = openApi.createRequestValidator({
  path: '/resource/{id}',
  method: HttpMethod.GET
})

validateRequest(request) // throws or returns true

const validateResponse = openApi.createResponseValidator({
  path: '/resource/{id}',
  method: HttpMethod.GET
})

validateResponse({ body: response.body, status }) // throws or returns true

Note

The underlying response & request validator packages use the Ajv schema validator library. Each time validators are created via createRequestValidator and createResponseValidator, a new Ajv() instance is also created. Since Ajv recommends instantiating once at initialization, these validators should also be instantiated just once during the lifecycle of the application to avoid any issues.

Middleware

Likewise, you can validate both requests and responses inside a Koa middleware method, using createValidatorMiddleware:

const openApi = await createOpenAPI(OPEN_API_URL)
const router = new SomeRouter()
router.get(
  '/resource/{id}',
  createValidatorMiddleware(
    openApi,
    {
      path: '/resource/{id}',
      method: HttpMethod.GET
    },
    { validateRequest: true, validateResponse: false } // optional arguments to determine what you want the middleware to validate. Both properties are true by default. Setting both variables to false results in a noop middleware.
  )
)

If a validation error occurs, the middleware will throw an OpenAPIValidatorMiddlewareError:

app.use(async (ctx, next) => {
  try {
    await next()
  } catch (err) {
    if (err instanceof OpenAPIValidatorMiddlewareError) {
      console.log(err.message) // e.g. Received error validating OpenAPI response: response.receivedAmount.value must match format "uint64"
      console.log(err.status) // e.g. 400
    }
  }
})