Body parser to handle MessagePack requests in LoopBack 4.
npm install @loopback/rest-msgpackThis module extends LoopBack with the ability to receive
MessagePack requests and transparently convert it to a
regular JavaScript object. It provides a BodyParser implementation and a
component to register it.
> Experimental packages provide early access to advanced or experimental
> functionality to get community feedback. Such modules are published to npm
> using 0.x.y versions. Their APIs and functionality may be subject to
> breaking changes in future releases.
``sh`
npm i @loopback/rest-msgpack --save
The component should be loaded in the constructor of your custom Application
class.
Start by importing the component class:
`ts`
import {MsgPackBodyParserComponent} from '@loopback/rest-msgpack';
In the constructor, add the component to your application:
`ts`
this.component(MsgPackBodyParserComponent);
The body parser will accept requests with the following MIME type
(Content-Type) blobs:
- application/msgpack
-
-
To accept MessagePack requests in a controller, amend the OpenAPI decorator to
include the MIME type as a possible request body.
For example, to update the Todo controller to accept MessagePack:
`typescript
import {post, getModelSchemaRef, requestBody} from '@loopback/rest';
class TodoController {
// Omitted constructor for bevity
@post('/todos')
async create(
@requestBody({
content: {
// Change existing or append a new request body accepted MIME type
'application/msgpack': {
schema: getModelSchemaRef(Todo, {
title: 'NewTodo',
exclude: ['id'],
}),
},
},
})
todo: // Keep the request body object type, since the body parser transparently
// converts it into a JavaScript object.
Omit
// For bevity, the function does not return anything. See
// 'Returning MessagePack Requests' below.
): void {
this.todoRepository.create(todo);
}
}
`
The MessagePack request payload will be transparently converted into a
JavaScript object and validated against the JSON Schema.
{% include note.html content="The body parser will not convert responses into application/msgpack automatically. This feature is being tracked by #6275" %}
To return MessagePack requests in a controller, amend the requestBody decorator
to include the MIME type as a possible response and use a parser library.
For example, to update the Todo controller to return in MessagePack:
`tsmsgpack5
// is re-exported by @loopback/rest-msgpack for convenience.
// It is recommended to bind it to context the inject it to benefit from
// dependency injection.
import {MsgPackBodyParserBindings, msgpack} from '@loopback/rest-msgpack';
import {inject} from '@loopback/core';
import {getModelSchemaRef, post, Response, RestBindings} from '@loopback/rest';
class TodoController {
private readonly _response: Response;
constructor(
// Omitted other dependency injections (e.g. repository) for bevity.
// Inject the Response object to the controller
@inject(RestBindings.Http.RESPONSE)
private readonly _res: Response,
) {}
@get('/todos', {
responses: {
'200': {
description: 'Array of Todo model instances',
content: {
// Update existing or amend new possible response
'application/msgpack': {
schema: {type: 'array', items: getModelSchemaRef(Todo)},
},
},
},
},
})
async findTodos(
@param.filter(Todo)
filter?: Filter
// Change function return type to Promise
): Promise
// Internally, LoopBack 4 will try to guess and override the Content-Type
// header, even after manually setting the headers.
// Buffers are automatically detected as .Response.end()
// We can use to bypass that.`
//
// See: https://github.com/loopbackio/loopback-next/issues/5168
//
this._res
.type('application/msgpack')
.end(msgpack().encode(this.todoRepository.find(filter)));
}
}
Run npm test` from the root folder.
See
all contributors.
MIT