feathers-objection

An Objection.js service adapter for FeathersJS

Installation

npm install feathers-objection --save

Documentation

Please refer to the Feathers database adapter documentation for more details or directly at:

• Extending - How to extend a database adapter
• Pagination and Sorting - How to use pagination and sorting for the database adapter
• Querying - The common adapter querying mechanism

Refer to the official Objection.js documention.

It works almost the same as the Knex service adapter, except it has all the benefits of the Objection ORM.

Models

Objection requires you to define Models for your tables:

// todo.js
class Todo extends Model {
  static tableName = 'todos'

  static jsonSchema = {
    type: 'object',
    required: ['text'],

    properties: {
      id: {type: 'integer'},
      text: {type: 'string'},
      complete: {type: 'boolean'}
    }
  }
}

export default Todo

When defining a service, you must provide the model:

app.use('/todos', service({
  model: Todo
})

Eager Queries

Eager queries is one way of solving the SQL database relational model in Feathers services, instead of relying with hooks.

Options

Note that all this eager related options are optional.

• allowedEager - relation expression to limit the allowed eager queries in the service. Defaults to '[]', meaning no eager queries allowed. See allowEager documentation.
• eagerFilters - option to impose compulsory eager filter. It takes an object or array of objects with the following properties:
  • expression - the relation expression that the filter will be applied.
  • filter - the filter function. It uses filterEager internally.
• namedEagerFilters - object containing named eager filter functions. Filter is opt-in via $eager parameter. See eager documentation.

Example:

app.use('/todos', service({
  model: Todo,
  allowedEager: 'subtask',
  namedEagerFilters: {
    unDone: function (builder) {
      builder.where('done', false)
    }
  },
  eagerFilters: [
    {
      expression: 'subtask',
      filter: function (builder) {
        builder.where('archived', true)
      }
    }
  ]
})

Use eager queries as follows:

// Get all todos and their unfinished tasks
app.service('/todos').find({
  query: {
    $eager: 'subtask(unDone)'
  }
})

See this article for more information.

Complete Example

Here's a complete example of a Feathers server with a todos SQLite service. We are using the Knex schema builder.

import feathers from 'feathers'
import rest from 'feathers-rest'
import bodyParser from 'body-parser'
import ObjectionService from '../lib'
import { Model } from 'objection'

const knex = require('knex')({
  client: 'sqlite3',
  connection: {
    filename: './db.sqlite'
  }
})

// Bind Objection.js
Model.knex(knex)

// Clean up our data. This is optional and is here
// because of our integration tests
knex.schema.dropTableIfExists('todos').then(function () {
  console.log('Dropped todos table')

  // Initialize your table
  return knex.schema.createTable('todos', function (table) {
    console.log('Creating todos table')
    table.increments('id')
    table.string('text')
    table.boolean('complete')
  })
})

// Create a feathers instance.
const app = feathers()
  // Enable REST services
  .configure(rest())
  // Turn on JSON parser for REST services
  .use(bodyParser.json())
  // Turn on URL-encoded parser for REST services
  .use(bodyParser.urlencoded({ extended: true }))

// Create an Objection Model
class Todo extends Model {
  static tableName = 'todos'

  static jsonSchema = {
    type: 'object',
    required: ['text'],

    properties: {
      id: {type: 'integer'},
      text: {type: 'string'},
      complete: {type: 'boolean'}
    }
  }
}

// Create Objection Feathers service with a default page size of 2 items
// and a maximum size of 4
app.use('/todos', ObjectionService({
  model: Todo,
  id: 'id',
  paginate: {
    default: 2,
    max: 4
  }
}))

app.use(function (error, req, res, next) {
  res.json(error)
})

console.log('Feathers Todo Objection service running on 127.0.0.1:3030')

You can run this example by using node server and going to localhost:3030/todos. You should see an empty array. That's because you don't have any Todos yet but you now have full CRUD for your new todos service!

Credits

This adapter is mainly a fork of the Knex feathers adapter by the Feathers team.

License

Copyright © 2016

Licensed under the MIT license.