Fastify-oapi NPM

fastify-oapi

Installation

npm install fastify-oapi

Compatibility matrix

`fastify-oapi` version	`fastify` version
`v1.x`	`v3.x`
`v2.x`	`v4.x` *

* Fastify v4 uses Ajv v8 per default. So it's not possible to use json schema draft-04 to fully align to OpenAPI v3.0 specification.

Simple Usage

import * as Fastify from "fastify";
import fastifyOpenApi, { getAjvOptions } from "fastify-oapi";

import * as controller from "./controller";

const specification = __dirname + "/openapi.yml"

// Extend Fastify Ajv options to be fully Open API v3 compliant
fastify = Fastify({
    ajv: getAjvOptions()
});

// Configure the plugin
fastify.register(fastifyOpenApi, {
    specification,
    controller,
});

await fastify.listen(3000);

Options

specification: A valid Open API v3 specification. It can be provided as a path, an URL or a JavaScript object.
resolution: Specify how to resolve controllers. See Controller Resolution.
controller: When using unique resolution mode, this value is used to resolve to a controller for the API. See Controller Resolution.
controllersDir: When using per-route or per-operation resolution mode, this value is used to determine where controllers are located. See Controller Resolution.
resolutionConfig: When using manual resolution mode, this value is used to configure how routes are mapped to controllers. See Controller Resolution.
prefix: Routes URL prefix (eg: /route with /v1 prefix create a /v1/route route).

Configure Fastify Ajv instance

To allow some openapi extensions fastify-oapi provides an ajv plugin. To enable the plugin, fastify-oapi provides the getAjvOptions() help.

import * as Fastify from "fastify";
import { getAjvOptions } from "fastify-oapi";

// Add ajv plugin with no options
fastify = Fastify({
    ajv: getAjvOptions()
});

// Extends Ajv custom options
fastify = Fastify({
    ajv: getAjvOptions(
        { removeAdditional: false }
    )
});

// Add other Ajv plugins
fastify = Fastify({
    ajv: getAjvOptions(
        { removeAdditional: false },
        [
            [otherPlugin, otherPluginOptions]
        ]
    )
});

## Controller Resolution

`fastify-oapi` can resolve controllers in multiple ways. It can be configured via the option `resolution`. This option accept the following values: `per-route`, `per-operation`, `unique` or `manual`.

#### per-route

The mode `per-route` is an automatic resolution mode. It looks for controllers based on the route URL. **It requires the `controllersDir` option.**

Examples:
- `/pets` routes to `pets.controller.js` in `controllersDir`.
- `/pets/:petId` routes to `pets.controller.js` in `controllersDir`.
- `/pets/getByStatus` routes to `pets.controller.js` in `controllersDir`.
- `/` routes to `root.controller.js` in `controllersDir`.
- `/:rootId` routes to `root.controller.js` in `controllersDir`.

#### per-operation

The mode `per-operation` looks for a `x-controller` tag in operation specification. **It requires the `controllersDir` option.**

Examples:
```yaml
"/pet":
  post:
    summary: Add a new pet to the store
    x-controller: pets.controller
    operationId: addPet
    # This operation routes to `pets.controller` in `controllerDir`
  put:
    summary: Update an existing pet
    x-controller: petupdate.controller
    operationId: updatePet
    # This operation routes to `petupdate.controller` in `controllerDir`

manual

The mode manual allows to configure how routes will be mapped to controllers. The resolutionConfig option is an object where keys could be the route URL, a prefix for the route URL or a RegExp that matche the route URL. If not found, it use the default to route to the default controller. It requires the resolutionConfig option.

Examples:

const options = {
    resolution: "manual",
    controllersDir: "./controllers",
    resolutionConfig: {
        "/pets": "pets.controller",
        "/orders/(.*)/action": "orders-action.controller",
        "/orders(.*)": "orders.controller",
        default: "default.controller"
    }
};

Using the configuration below:

/pets routes to pets.controller.js in controllersDir.
/pets/:petId routes to pets.controller.js in controllersDir.
/pets/getByStatus routes to pets.controller.js in controllersDir.
/orders routes to orders.controller.js in controllersDir.
/orders/:orderId routes to orders.controller.js in controllersDir.
/orders/:orderId/action routes to orders-action.controller.js in controllersDir.
/anything routes to default.controller.js in controllersDir.

unique

The mode unique is the simpler mode. It allows to configure an unique controller for the whole API by using the controller option. It requires the controller option.

default resolution

If the resolution option is not provided, the engine will try to look for options to determine the resolution mode:

If controller is defined, use the unique resolution mode.
If resolutionConfig is defined, use the manual resolution mode.
If controllersDir is defined, use the per-route resolution mode.

OpenAPI extensions

x-partial

fastify-oapi supports the x-partial Open API extension which allows to override required configuration of JSON Schemas. It is useful to easily allow some operations to returns partial entities while keeping shared schemas intact.

Examples:

/partial:
  get:
    operationId: getPartial
    summary: x-partial response
    responses:
      "200":
        description: partial
        content:
          application/json:
            schema:
              x-partial: true
              type: object
              properties:
                response:
                type: string
              required:
                - response
      "201":
        description: partial $ref
        content:
          application/json:
            schema:
              x-partial: true
              $ref: "#/components/schemas/ResponseObject"