没有 opts 的 JSData 加载关系

JSData load relations without opts

当通过映射器急切加载关系时,opts 参数会传递给加载的关系。在我的例子中,这打破了 api 。例如:

storyMapper.findAll({ title: 'foobar' }, { with: ['user'] });

这导致两个请求:

GET /stories?title=foobar
GET /users?title=foobar

我可能遗漏了一些东西,但我希望使用定义的关系,以便首先加载故事,它是 userId 字段读取,第二个查询类似于

GET /users/<the id>

或至少

GET /users?where=<id in <the id>>

所以我的问题是;我可以改变它的行为还是我需要在每个故事加载后使用 loadRelations


代码示例:

// user schema

import { Schema } from 'js-data';

export const user = new Schema({
    $schema: 'http://json-schema.org/draft-04/schema#',
    title: 'User',
    description: 'Schema for User records',
    type: 'object',
    properties: {
        _id: { type: 'string' },
        username: { type: 'string' },
        email: { type: 'string' },
        password: { type: 'string' },
    },

    required: ['username', 'email', 'password'],
});

// story schema

import { Schema } from 'js-data';

export const story = new Schema({
    $schema: 'http://json-schema.org/draft-04/schema#',
    title: 'Story',
    description: 'Schema for Story records',
    type: 'object',
    properties: {
        _id: { type: 'string' },
        title: { type: 'string', default: '' },
        userId: { type: ['string', 'null'] },
        username: { type: ['string', 'null'] },
    },
    required: ['title'],
});

// user mapper

this.store.defineMapper('user', {
    mapperClass: ObservableMapper,
    recordClass: User,
    endpoint: 'users',
    idAttribute: '_id',
    schema: schemas.user,
    relations: relations.user,
})

// story mapper

this.store.defineMapper('story', {
    mapperClass: ObservableMapper,
    recordClass: Story,
    endpoint: 'storys',
    idAttribute: '_id',
    schema: schemas.story,
    relations: relations.story,
})

// user relations

export const user = {
    hasMany: {
        world: {
            foreignKey: 'userId',
            localField: 'worlds',
        },
    },
};

// story relations

export const world = {
    belongsTo: {
        user: {
            foreignKey: 'userId',
            localField: 'user',
        },
    },
};

GET /stories?title=foobar 返回的示例数据:

{
  "_id": "546e53dcedee82d542000003",
  "userId": "526e8617964fd22d2b000001",
  "username": "Someone",
  "title": "Lorem Ipsum"
}

你错过了 User-Story 关系的另一面:

// user relations
export const user = {
  hasMany: {
    story: {
      foreignKey: 'userId',
      localField: 'stories'
    },
    world: {
      foreignKey: 'userId',
      localField: 'worlds'
    }
  }
};

现在,当您实际发出请求时,您有两个选择:

选项 1 - 多个请求

这需要您的服务器理解 "where" 查询字符串参数:

store.findAll('story', { title: 'foobar' }, { with: ['user'] })

这里有一个 plunker 演示:https://plnkr.co/edit/UCFJNg?p=preview

plunker 示例提出两个请求:

  • GET /stories?title=foobar
  • GET /users?title=foobar&where={"_id":{"in":[123,234]}}

选项 2 - 单个请求

这需要您的服务器理解 "with" 查询字符串参数:

store.findAll('story', { title: 'foobar' }, { params: { with: ['user'] } })

这里有一个 plunker 演示:https://plnkr.co/edit/M6quP4?p=preview

plunker 示例仅发出一个请求,并期望用户嵌入到服务器响应的故事中:

  • GET /stories?with=user&title=foobar

备注

这是 HTTP 适配器的一个怪癖。对于所有其他适配器,使用 with 选项会如您所愿,您不必乱用 params 选项。