This module provides a common set of interfaces for interacting with databases.
This module provides data access facilities to various databases and services as well as the constructs for modeling and accessing those data.
npm install --save @loopback/repositoryAt the moment, we only have implementations of Repository based on LoopBack
3.x loopback-datasource-juggler and connectors. The following steps illustrate
how to define repositories and use them with controllers.
The repository module provides APIs to define LoopBack 3.x data sources and models. For example,
// src/datasources/db.datasource.ts
import {juggler} from '@loopback/repository';
export const db: juggler.DataSource = new juggler.DataSource({
name: 'db',
connector: 'memory',
});// src/models/note.model.ts
import {model, Entity, property} from '@loopback/repository';
@model()
export class Note extends Entity {
@property({id: true})
id: string;
@property()
title: string;
@property()
content: string;
}
export interface NoteRelations {
// describe navigational properties here
}
export type NoteWithRelations = Note & NoteRelations;NOTE: There is no declarative support for data source and model yet in LoopBack 4. These constructs need to be created programmatically as illustrated above.
A repository can be created by extending DefaultCrudRepository and using
dependency injection to resolve the datasource.
// src/repositories/note.repository.ts
import {DefaultCrudRepository, DataSourceType} from '@loopback/repository';
import {Note, NoteRelations} from '../models';
import {inject} from '@loopback/core';
export class NoteRepository extends DefaultCrudRepository<
Note,
typeof Note.prototype.id,
NoteRelations
> {
constructor(@inject('datasources.db') protected dataSource: DataSourceType) {
super(Note, dataSource);
}
}Controllers serve as handlers for API requests. We declare controllers as classes with optional dependency injection by decorating constructor parameters or properties.
// src/controllers/note.controller.ts
import {repository} from '@loopback/repository';
import {NoteRepository} from '../repositories';
import {Note} from '../models';
import {post, requestBody, get, param} from '@loopback/rest';
export class NoteController {
constructor(
// Use constructor dependency injection to set up the repository
@repository(NoteRepository) public noteRepo: NoteRepository,
) {}
// Create a new note
@post('/note')
create(@requestBody() data: Note) {
return this.noteRepo.create(data);
}
// Find notes by title
@get('/note/{title}')
findByTitle(@param.path.string('title') title: string) {
return this.noteRepo.find({where: {title}});
}
}A Repository Mixin is available for Application that provides convenience
methods for binding and instantiating a repository class. Bound instances can be
used anywhere in your application using Dependency Injection. The
.repository(RepositoryClass) function can be used to bind a repository class
to an Application. The mixin will also instantiate any repositories declared by
a component in its constructor using the repositories key.
Repositories will be bound to the key repositories.RepositoryClass where
RepositoryClass is the name of the Repository class being bound.
We'll use BootMixin on top of RepositoryMixin so that Repository bindings
can be taken care of automatically at boot time before the application starts.
import {BootMixin} from '@loopback/boot';
import {ApplicationConfig} from '@loopback/core';
import {RepositoryMixin} from '@loopback/repository';
import {RestApplication} from '@loopback/rest';
import {db} from './datasources/db.datasource';
export class RepoApplication extends BootMixin(
RepositoryMixin(RestApplication),
) {
constructor(options?: ApplicationConfig) {
super(options);
this.projectRoot = __dirname;
this.dataSource(db);
}
}- https://martinfowler.com/eaaCatalog/repository.html
- https://msdn.microsoft.com/en-us/library/ff649690.aspx
- http://docs.spring.io/spring-data/data-commons/docs/2.0.0.M3/reference/html/#repositories
Run npm test from the root folder.
See all contributors.
MIT