Fastify decorators
### Request handlers
Here the list of available HTTP methods decorators:
**@GET**, **@HEAD**, **@PATCH**, **@POST**, **@PUT**, **@OPTIONS**, **@DELETE**
There's also one special decorator for all methods: **@ALL**
#### Limitations:
- Decorators can't be mixed, and you can use only one decorator per class/method.
### Signatures:
Decorators have same signature, which consist of two overloads:
_First overload_:
| name | type | required | default | description |
|---------|---------------------------|:--------:|:-------:|--------------------------------------------------|
| url | `string` | no | `/` | Route url which will be passed to Fastify |
| options | [`RouteShorthandOptions`] | no | `{}` | Config for route which will be passed to Fastify |
_Second overload_:
| name | type | required | default | description |
|---------|-----------------|:--------:|:-------:|----------------------------------------------|
| url | `RouteOptions` | no | `{}` | Route url and config to be passed to Fastify |
### Request handler per class
Every handler should extend base `RequestHandler` class:
```ts
import { GET, RequestHandler } from 'fastify-decorators';
@GET('/')
class MyRequestHandler extends RequestHandler {
async handler() {} // concrete implementation of abstract method in RequestHandler
}
```
### Request handler per method
In controllers you can decorate every method with one of the request decorators:
```ts
import { FastifyReply, FastifyRequest } from 'fastify';
import { Controller, GET } from 'fastify-decorators';
@Controller()
class MyController {
@GET()
async handler(request: FastifyRequest, reply: FastifyReply) {}
}
```
### Creating hooks
There are also decorator which allows using [Fastify Hooks]:
```ts
import { GET, Hook } from 'fastify-decorators';
@GET('/')
export default class Handler extends RequestHandler {
public handle(): Promise {
return Promise.reject({ code: 'NOT_IMPLEMENTED' });
}
@Hook('onSend')
async onSend(request, reply) {
reply.removeHeader('X-Powered-By');
}
}
```
### Error handling
`fastify-decorators` provides abilities to handle error with `@ErrorHandler` decorator.
Decorator may accept error code or type to handle or be empty which means will handle all errors. Let's take a look on example:
```ts
import { FastifyReply, FastifyRequest } from 'fastify';
import { ErrorHandler, GET, RequestHandler } from 'fastify-decorators';
@GET('/handler-with-error')
export default class HandlerWithErrorHandler extends RequestHandler {
public handle(): Promise {
return Promise.reject({ code: 'NOT_IMPLEMENTED' });
}
@ErrorHandler('NOT_IMPLEMENTED')
handleNotImplemented(error: Error, request: FastifyRequest, reply: FastifyReply): void {
reply.status(422).send({ message: 'Not implemented' });
}
}
```
[fastify hooks]: https://github.com/fastify/fastify/blob/master/docs/Hooks.md
[`routeshorthandoptions`]: https://github.com/fastify/fastify/blob/master/docs/Routes.md#shorthand-declaration