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loopback

v0.9.0

Install

slnode install loopback -g

Server API

Client API

TODO

App

Create an loopback application.

var loopback = require('loopback');
var app = loopback();

app.get('/', function(req, res){
  res.send('hello world');
});

app.listen(3000);

Notes:

app.model(Model)

Expose a Model to remote clients.

// create a testing data source
var memory = loopback.memory();
var Color = memory.createModel('color', {name: String});
Color.attachTo(memory);

app.model(Color);
app.use(loopback.rest());

Note: this will expose all shared methods on the model.

app.models()

Get the app's exposed models.

var models = app.models();

models.forEach(function (Model) {
  console.log(Model.modelName); // color
});

Model

An Loopback Model is a vanilla JavaScript class constructor with an attached set of properties and options. A Model instance is created by passing a data object containing properties to the Model constructor. A Model constructor will clean the object passed to it and only set the values matching the properties you define.

// valid color
var Color = loopback.createModel('color', {name: String});
var red = new Color({name: 'red'});
console.log(red.name); // red

// invalid color
var foo = new Color({bar: 'bat baz'});
console.log(foo.bar); // undefined

Properties

A model defines a list of property names, types and other validation metadata. A DataSource uses this definition to validate a Model during operations such as save().

Options

Some DataSources may support additional Model options.

Define an loopback model.

var User = loopback.createModel('user', {
  first: String,
  last: String,
  age: Number
});

Validation (expiremental)

Model.validatesFormatOf(property, options)

Require a model to include a property that matches the given format.

User.validatesFormat('name', {with: /\w+/});

Model.validatesPresenceOf(properties...)

Require a model to include a property to be considered valid.

User.validatesPresenceOf('first', 'last', 'age');

Model.validatesLengthOf(property, options)

Require a property length to be within a specified range.

User.validatesLengthOf('password', {min: 5, message: {min: 'Password is too short'}});

Model.validatesInclusionOf(property, options)

Require a value for property to be in the specified array.

User.validatesInclusionOf('gender', {in: ['male', 'female']});

Model.validatesExclusionOf(property, options)

Require a value for property to not exist in the specified array.

User.validatesExclusionOf('domain', {in: ['www', 'billing', 'admin']});

Model.validatesNumericalityOf(property, options)

Require a value for property to be a specific type of Number.

User.validatesNumericalityOf('age', {int: true});

Model.validatesUniquenessOf(property, options)

Ensure the value for property is unique.

User.validatesUniquenessOf('email', {message: 'email is not unique'});

Note: not available for all connectors.

myModel.isValid()

Validate the model instance.

user.isValid(function (valid) {
    if (!valid) {
        user.errors // hash of errors {attr: [errmessage, errmessage, ...], attr: ...}    
    }
});

Model.properties

An object containing a normalized set of properties supplied to loopback.createModel(name, properties).

Example:

var props = {
  a: String,
  b: {type: 'Number'},
  c: {type: 'String', min: 10, max: 100},
  d: Date,
  e: loopback.GeoPoint
};

var MyModel = loopback.createModel('foo', props);

console.log(MyModel.properties);

Outputs:

{
  "a": {type: String},
  "b": {type: Number},
  "c": {
    "type": String,
    "min": 10,
    "max": 100
  },
  "d": {type: Date},
  "e": {type: GeoPoint},
  "id": {
    "id": 1
  }
}

Model.attachTo(dataSource)

Attach a model to a DataSource. Attaching a DataSource updates the model with additional methods and behaviors.

var oracle = loopback.createDataSource({
  connector: require('loopback-connector-oracle'),
  host: '111.22.333.44',
  database: 'MYDB',
  username: 'username',
  password: 'password'
});

User.attachTo(oracle);

Note: until a model is attached to a data source it will not have any attached methods.

CRUD and Query Mixins

Mixins are added by attaching a vanilla model to a data source with a connector. Each connector enables its own set of operations that are attached to a Model as methods. To see available methods for a data source with a connector call dataSource.operations().

Static Methods

Model.create(data, [callback])

Create an instance of Model with given data and save to the attached data source. Callback is optional.

User.create({first: 'Joe', last: 'Bob'}, function(err, user) {
  console.log(user instanceof User); // true
});

Note: You must include a callback and use the created model provided in the callback if your code depends on your model being saved or having an id.

Model.count([query], callback)

Query count of Model instances in data source. Optional query param allows to count filtered set of Model instances.

User.count({approved: true}, function(err, count) {
  console.log(count); // 2081
});
Model.find(filter, callback)

Find all instances of Model, matched by query. Fields used for filter and sort should be declared with {index: true} in model definition.

filter

  • where Object { key: val, key2: {gt: 'val2'}}
  • include String, Object or Array.
  • order String
  • limit Number
  • skip Number

Find the second page of 10 users over age 21 in descending order.

User.find({where: {age: {gt: 21}}, order: 'age DESC', limit: 10, skip: 10})

Note: See the specific connector's docs for more info.

Model.destroyAll(callback)

Delete all Model instances from data source. Note: destroyAll method does not perform destroy hooks.

Model.findById(id, callback)

Find instance by id.

User.findById(23, function(err, user) {
  console.info(user.id); // 23
});
Model.findOne(where, callback)

Find a single instance that matches the given where expression.

User.findOne({id: 23}, function(err, user) {
  console.info(user.id); // 23
});
Model.upsert(data, callback)

Update when record with id=data.id found, insert otherwise. Note: no setters, validations or hooks applied when using upsert.

Custom Static Methods

Define a static model method.

User.login = function (username, password, fn) {
  var passwordHash = hashPassword(password);
  this.findOne({username: username}, function (err, user) {
    var failErr = new Error('login failed');

    if(err) {
      fn(err);
    } else if(!user) {
      fn(failErr);
    } else if(user.password === passwordHash) {
      MySessionModel.create({userId: user.id}, function (err, session) {
        fn(null, session.id);
      });
    } else {
      fn(failErr);
    }
  });
}

Setup the static model method to be exposed to clients as a remote method.

loopback.remoteMethod(
  User.login,
  {
    accepts: [
      {arg: 'username', type: 'string', required: true},
      {arg: 'password', type: 'string', required: true}
    ],
    returns: {arg: 'sessionId', type: 'any'},
    http: {path: '/sign-in'}
  }
);

Instance Methods

model.save([options], [callback])

Save an instance of a Model to the attached data source.

var joe = new User({first: 'Joe', last: 'Bob'});
joe.save(function(err, user) {
  if(user.errors) {
    console.log(user.errors);
  } else {
    console.log(user.id);
  }
});
model.updateAttributes(data, [callback])

Save specified attributes to the attached data source.

user.updateAttributes({
  first: 'updatedFirst',
  name: 'updatedLast'
}, fn);
model.destroy([callback])

Remove a model from the attached data source.

model.destroy(function(err) {
  // model instance destroyed
});
Custom Instance Methods

Define an instance method.

User.prototype.logout = function (fn) {
  MySessionModel.destroyAll({userId: this.id}, fn);
}

Define a remote model instance method.

loopback.remoteMethod(User.prototype.logout);

Remote Methods

Both instance and static methods can be exposed to clients. A remote method must accept a callback with the conventional fn(err, result, ...) signature.

loopback.remoteMethod(fn, [options]);

Expose a remote method.

Product.stats = function(fn) {
  myApi.getStats('products', fn);
}

loopback.remoteMethod(
  Product.stats,
  {
    returns: {arg: 'stats', type: 'array'},
    http: {path: '/info', verb: 'get'}
  }
);

Options

  • accepts - (optional) an arguments description specifying the remote method's arguments. A
  • returns - (optional) an arguments description specifying the remote methods callback arguments.
  • http - (advanced / optional, object) http routing info
  • http.path - the path relative to the model the method will be exposed at. May be a path fragment (eg. '/:myArg') which will be populated by an arg of the same name in the accepts description. For example the stats method above will be at the whole path /products/stats.
  • http.verb - (get, post, put, del, all) - the route verb the method will be available from.

Argument Description

An arguments description defines either a single argument as an object or an ordered set of arguments as an array.

// examples
{arg: 'myArg', type: 'number'}

[
  {arg: 'arg1', type: 'number', required: true},
  {arg: 'arg2', type: 'array'}
]

Types

Each argument may define any of the loopback types.

Notes:

  • The callback is an assumed argument and does not need to be specified in the accepts array.
  • The err argument is also assumed and does not need to be specified in the returns array.

Remote Hooks

Run a function before or after a remote method is called by a client.

// *.save === prototype.save
User.beforeRemote('*.save', function(ctx, user, next) {
  if(ctx.user) {
    next();
  } else {
    next(new Error('must be logged in to update'))
  }
});

User.afterRemote('*.save', function(ctx, user, next) {
  console.log('user has been saved', user);
  next();
});

Remote hooks also support wildcards. Run a function before any remote method is called.

// ** will match both prototype.* and *.*
User.beforeRemote('**', function(ctx, user, next) {
  console.log(ctx.methodString, 'was invoked remotely'); // users.prototype.save was invoked remotely
  next();
});

Other wildcard examples

// run before any static method eg. User.find
User.beforeRemote('*', ...);

// run before any instance method eg. User.prototype.save
User.beforeRemote('prototype.*', ...);

// prevent password hashes from being sent to clients
User.afterRemote('**', function (ctx, user, next) {
  if(ctx.result) {
    if(Array.isArray(ctx.result)) {
      ctx.result.forEach(function (result) {
        result.password = undefined;
      });
    } else {
      ctx.result.password = undefined;
    }
  }

  next();
});

Context

Remote hooks are provided with a Context ctx object which contains transport specific data (eg. for http: req and res). The ctx object also has a set of consistent apis across transports.

ctx.user

A Model representing the user calling the method remotely. Note: this is undefined if the remote method is not invoked by a logged in user.

ctx.result

During afterRemote hooks, ctx.result will contain the data about to be sent to a client. Modify this object to transform data before it is sent.

Rest

When loopback.rest is used the following ctx properties are available.

ctx.req

The express ServerRequest object. See full documentation.

ctx.res

The express ServerResponse object. See full documentation.

Access the raw req object for the remote method call.

Relationships

Model.hasMany(Model)

Define a "one to many" relationship.

// by referencing model
Book.hasMany(Chapter);
// specify the name
Book.hasMany('chapters', {model: Chapter});

Query and create the related models.

Book.create(function(err, book) {
  // create a chapter instance
  // ready to be saved in the data source
  var chapter = book.chapters.build({name: 'Chapter 1'});
  
  // save the new chapter
  chapter.save();
  
  // you can also call the Chapter.create method with
  // the `chapters` property which will build a chapter
  // instance and save the it in the data source
  book.chapters.create({name: 'Chapter 2'}, function(err, savedChapter) {
    // this callback is optional
  });

  // query chapters for the book using the 
  book.chapters(function(err, chapters) {
    // all chapters with bookId = book.id
    console.log(chapters);
  });
  
  book.chapters({where: {name: 'test'}, function(err, chapters) {
    // all chapters with bookId = book.id and name = 'test'
    console.log(chapters);
  });
});
Model.hasAndBelongsToMany()

TODO: implement / document

Shared Methods

Any static or instance method can be decorated as shared. These methods are exposed over the provided transport (eg. loopback.rest).

Data Source

An Loopback DataSource provides Models with the ability to manipulate data. Attaching a DataSource to a Model adds instance methods and static methods to the Model. The added methods may be remote methods.

Define a data source for persisting models.

var oracle = loopback.createDataSource({
  connector: 'oracle',
  host: '111.22.333.44',
  database: 'MYDB',
  username: 'username',
  password: 'password'
});

dataSource.createModel(name, properties, options)

Define a model and attach it to a DataSource.

var Color = oracle.createModel('color', {name: String});

dataSource.discoverModelDefinitions([username], fn)

Discover a set of model definitions (table or collection names) based on tables or collections in a data source.

oracle.discoverModelDefinitions(function (err, models) {
  models.forEach(function (def) {
    // def.name ~ the model name
    oracle.discoverSchema(null, def.name, function (err, schema) {
      console.log(schema);
    });
  });
});

dataSource.discoverSchema([owner], name, fn)

Discover the schema of a specific table or collection.

Example schema from oracle connector:

{
  "name": "Product",
  "options": {
    "idInjection": false,
    "oracle": {
      "schema": "BLACKPOOL",
      "table": "PRODUCT"
    }
  },
  "properties": {
    "id": {
      "type": "String",
      "required": true,
      "length": 20,
      "id": 1,
      "oracle": {
        "columnName": "ID",
        "dataType": "VARCHAR2",
        "dataLength": 20,
        "nullable": "N"
      }
    },
    "name": {
      "type": "String",
      "required": false,
      "length": 64,
      "oracle": {
        "columnName": "NAME",
        "dataType": "VARCHAR2",
        "dataLength": 64,
        "nullable": "Y"
      }
    },
    "audibleRange": {
      "type": "Number",
      "required": false,
      "length": 22,
      "oracle": {
        "columnName": "AUDIBLE_RANGE",
        "dataType": "NUMBER",
        "dataLength": 22,
        "nullable": "Y"
      }
    },
    "effectiveRange": {
      "type": "Number",
      "required": false,
      "length": 22,
      "oracle": {
        "columnName": "EFFECTIVE_RANGE",
        "dataType": "NUMBER",
        "dataLength": 22,
        "nullable": "Y"
      }
    },
    "rounds": {
      "type": "Number",
      "required": false,
      "length": 22,
      "oracle": {
        "columnName": "ROUNDS",
        "dataType": "NUMBER",
        "dataLength": 22,
        "nullable": "Y"
      }
    },
    "extras": {
      "type": "String",
      "required": false,
      "length": 64,
      "oracle": {
        "columnName": "EXTRAS",
        "dataType": "VARCHAR2",
        "dataLength": 64,
        "nullable": "Y"
      }
    },
    "fireModes": {
      "type": "String",
      "required": false,
      "length": 64,
      "oracle": {
        "columnName": "FIRE_MODES",
        "dataType": "VARCHAR2",
        "dataLength": 64,
        "nullable": "Y"
      }
    }
  }
}

dataSource.enableRemote(operation)

Enable remote access to a data source operation. Each connector has its own set of set remotely enabled and disabled operations. You can always list these by calling dataSource.operations().

dataSource.disableRemote(operation)

Disable remote access to a data source operation. Each connector has its own set of set enabled and disabled operations. You can always list these by calling dataSource.operations().

// all rest data source operations are
// disabled by default
var oracle = loopback.createDataSource({
  connector: require('loopback-connector-oracle'),
  host: '...',
  ...
});

// or only disable it as a remote method
oracle.disableRemote('destroyAll');

Notes:

  • disabled operations will not be added to attached models
  • disabling the remoting for a method only affects client access (it will still be available from server models)
  • data sources must enable / disable operations before attaching or creating models

dataSource.operations()

List the enabled and disabled operations.

console.log(oracle.operations());

Output:

{
  find: {
    remoteEnabled: true,
    accepts: [...],
    returns: [...]
    enabled: true
  },
  save: {
    remoteEnabled: true,
    prototype: true,
    accepts: [...],
    returns: [...],
    enabled: true
  },
  ...
}

Connectors

Create a data source with a specific connector. See available connectors for specific connector documentation.

var memory = loopback.createDataSource({
  connector: loopback.Memory
});

Available Connectors

Installing Connectors

Include the connector in your package.json dependencies and run npm install.

{
  "dependencies": {
    "loopback-connector-oracle": "latest"
  }
}

GeoPoint

Use the GeoPoint class.

var GeoPoint = require('loopback').GeoPoint;

Embed a latitude / longitude point in a Model.

var CoffeeShop = loopback.createModel('coffee-shop', {
  location: 'GeoPoint'
});

Loopback Model's with a GeoPoint property and an attached DataSource may be queried using geo spatial filters and sorting.

Find the 3 nearest coffee shops.

CoffeeShop.attachTo(oracle);
var here = new GeoPoint({lat: 10.32424, lng: 5.84978});
CoffeeShop.find({where: {location: {near: here}}, limit:3}, function(err, nearbyShops) {
  console.info(nearbyShops); // [CoffeeShop, ...]
});

geoPoint.distanceTo(geoPoint, options)

Get the distance to another GeoPoint.

var here = new GeoPoint({lat: 10, lng: 10});
var there = new GeoPoint({lat: 5, lng: 5});
console.log(here.distanceTo(there, {type: 'miles'})); // 438

GeoPoint.distanceBetween(a, b, options)

Get the distance between two points.

GeoPoint.distanceBetween(here, there, {type: 'miles'}) // 438

Distance Types

Note: all distance methods use miles by default.

  • miles
  • radians
  • kilometers
  • meters
  • miles
  • feet
  • degrees

geoPoint.lat

The latitude point in degrees. Range: -90 to 90.

geoPoint.lng

The longitude point in degrees. Range: -180 to 180.

Loopback Types

Various APIs in Loopback accept type descriptions (eg. remote methods, loopback.createModel()). The following is a list of supported types.

  • null - JSON null
  • Boolean - JSON boolean
  • Number - JSON number
  • String - JSON string
  • Object - JSON object
  • Array - JSON array
  • Date - a JavaScript date object
  • Buffer - a node.js Buffer object
  • GeoPoint - an loopback GeoPoint object. TODO

Bundled Models

The Loopback library is unopinioned in the way you define your app's data and logic. Loopback also bundles useful pre-built models for common use cases.

  • User - register and authenticate users of your app locally or against 3rd party services.
  • Notification - TODO create, store, schedule and send push notifications to your app users.
  • Email - send emails to your app users using smtp or 3rd party services.
  • Job - TODO schedule arbitrary code to run at a given time.

Defining a model with loopback.createModel() is really just extending the base loopback.Model type using loopback.Model.extend(). The bundled models extend from the base loopback.Model allowing you to extend them arbitrarily.

User Model

Register and authenticate users of your app locally or against 3rd party services.

Create a User Model

Extend a vanilla Loopback model using the built in User model.

// create a data source
var memory = loopback.memory();

// define a User model
var User = loopback.User.extend('user');

// attach to the memory connector
User.attachTo(memory);

// also attach the session model to a data source
User.session.attachTo(memory);

// expose over the app's api
app.model(User);

Note: By default the loopback.User model uses the loopback.Session model to persist sessions. You can change this by setting the session property.

Note: You must attach both the User and User.session model's to a data source!

// define a custom session model    
var MySession = loopback.Session.extend('my-session');

// define a custom User model
var User = loopback.User.extend('user');

// use the custom session model
User.session = MySession;

// attaching to

User Creation

Create a user like any other model.

// username and password are not required
User.create({email: 'foo@bar.com', password: 'bar'}, function(err, user) {
  console.log(user);
});

Authentication Strategies (Using Passport.js)

Setup an authentication strategy.

See all available providers from passport.js.

// first add your model to your app
app.model(User);

// by default your User model has a local strategy similar to below

// customize your own
// disable the default local strategy
User.useLocalStrategy(false);

// create a custom strategy
var LocalStrategy = require('passport-local').Strategy;
passport.use(new LocalStrategy(function(username, password, done) {
  User.findOne({ username: username }, function(err, user) {
    if (err) { return done(err); }
    if (!user) { return done(null, false, { message: 'Unknown user ' + username }); }
    user.comparePassword(password, function(err, isMatch) {
      if (err) return done(err);
      if(isMatch) {
        return done(null, user);
      } else {
        return done(null, false, { message: 'Invalid password' });
      }
    });
  });
}));

Login a User

Create a session for a user.

User.login({username: 'foo', password: 'bar'}, function(err, session) {
  console.log(session);
});

REST

You must provide a username and password over rest. To ensure these values are encrypted, include these as part of the body and make sure you are serving your app over https (through a proxy or using the https node server).

POST

  /users/login
  ...
  {
    "email": "foo@bar.com",
    "password": "bar"
  }

  ...

  200 OK
  {
    "sid": "1234abcdefg",
    "uid": "123"
  }

Logout a User

NODE

// login a user and logout User.login({"email": "foo@bar.com", "password": "bar"}, function(err, session) { User.logout(session.id, function(err) { // user logged out }); });

// logout a user (server side only) User.findOne({email: 'foo@bar.com'}, function(err, user) { user.logout(); });

REST

Note: When calling this method remotely, the first argument will be populated with the current user's id. If the caller is not logged in the method will fail with an error status code 401.

Verify Email Addresses

Require a user to verify their email address before being able to login. This will send an email to the user containing a link to verify their address. Once the user follows the link they will be redirected to / and be able to login normally.

User.requireEmailVerfication = true;
User.afterRemote('create', function(ctx, user, next) {
  var options = {
    type: 'email',
    to: user.email,
    from: 'noreply@myapp.com',
    subject: 'Thanks for Registering at FooBar',
    text: 'Please verify your email address!'
    template: 'verify.ejs',
    redirect: '/'
  };
  
  user.verify(options, next);
});

Send Reset Password Email

Send an email to the user's supplied email address containing a link to reset their password.

User.reset(email, function(err) {
  console.log('email sent');
});

Remote Password Reset

The password reset email will send users to a page rendered by loopback with fields required to reset the user's password. You may customize this template by defining a resetTemplate setting.

User.settings.resetTemplate = 'reset.ejs';

Remote Password Reset Confirmation

Confirm the password reset.

User.confirmReset(token, function(err) {
  console.log(err || 'your password was reset');
});

Session Model

Identify users by creating sessions when they connect to your loopback app. By default the loopback.User model uses the loopback.Session model to persist sessions. You can change this by setting the session property.

// define a custom session model    
var MySession = loopback.Session.extend('my-session');

// define a custom User model
var User = loopback.User.extend('user');

// use the custom session model
User.session = MySession;

// attach both Session and User to a data source
User.attachTo(loopback.memory());
MySession.attachTo(loopback.memory());

Email Model

Send emails from your loopback app.

REST Router

Expose models over rest using the loopback.rest router.

app.use(loopback.rest());

REST Documentation

View generated REST documentation by visiting: http://localhost:3000/_docs.

SocketIO Middleware Not Available

Coming Soon - Expose models over socket.io using the loopback.sio() middleware.

app.use(loopback.sio);