The feathers-session behavior uses the feathers-authentication-client to authenticate with a Feathers server. Three of the DataInterface methods are used:

• createData attempts to authenticate with the Feathers server, which upon success returns a JSON Web Token (JWT). The JWT contains a payload with information about the current session. That payload is returned as the session object.
• getData validates a stored JWT and returns its payload if the token hasn't expired.
• destroyData unauthenticates from the server and discards the JWT token on the client.

Use

Setting up the Feathers Client is a prerequisite for using this behavior. See the can-connect-feathers page for an example of a basic Feathers Client configuration. With the Feathers client setup, it can be used with the feathers-session behavior as demonstrated in the example, below.

// models/session.js
var connect = require('can-connect');
var DefineMap = require('can-define/map/');

var feathersSessionBehavior = require('can-connect-feathers/session');
var dataParse = require('can-connect/data/parse/');
var construct = require('can-connect/constructor/');
var constructStore = require('can-connect/constructor/store/');
var constructCallbacksOnce = require('can-connect/constructor/callbacks-once/');
var canMap = require('can-connect/can/map/');
var canRef = require('can-connect/can/ref/');
var dataCallbacks = require('can-connect/data/callbacks/');
// Bring in your user model to setup the relation in your DefineMap.
var User = require('./user');

// Bring in the feathersClient instance.
var feathersClient = require('./feathers');

export const Session = DefineMap.extend('Session', {
  seal: false
}, {
  exp: 'any',
  userId: 'any',
  user: {
    Type: User,
    // Automatically populate the user data when a userId is received.
    get (lastSetVal, resolve) {
      if (lastSetVal) {
        return lastSetVal;
      }
      if (this.userId) {
        User.get({_id: this.userId}).then(resolve);
      }
    }
  }
});

connect([
  // Include the feathers session behavior in the behaviors list.
  feathersSession,
  dataParse,
  canMap,
  canRef,
  construct,
  constructStore,
  constructCallbacksOnce,
  // Include the realtime behavior.
  realtime,
  dataCallbacks
], {
  // Pass the feathers client as the `feathersClient` property.
  feathersClient: feathersClient,
  idProp: 'exp',
  Map: Session,
  name: 'session'
});

Obtaining current session data

Once authentication has been established, the Map or DefineMap provided as the Map option on the can-connect Model will have a new current property defined. So, if you passed a Session object, Session.current will always hold the current session data. This greatly simplifies the session property in your application ViewModel. Here's an abbreviated example.

import Session from 'my-app/models/session';

const AppViewModel = DefineMap.extend({
  session: {
    get () {
      return Session.current;
    }
  }
});

That's it! The session property in the above example will automatically populate when the user authenticates.

Handling OAuth Logins

The feathers-session behavior is preconfigured to listen to login messages coming in over the feathers-authentication-popups authAgent. When any message is received through the authAgent, its validity is checked. If it's a valid JWT token, a Session instance will be created automatically. This will both populate Session.current and dispatch a created event on the connected Session Map.