awill1988/xdomls

crossdomain for localstorage

xdomls is a localStorage augmentation that uses postMessage to communicate with a child frame to achieve persistent storage across domains. it has the ability to automatically sync between the cross browser frame and the top localStorage object without any configuration, making native use of localStorage across different domains frictionless.

getting started

• upload iframe/build/index.html to a common domain or public s3 bucket

bundled apps

npm install xdomls

XDOMLS = require('xdomls')

normal pages

including the script client/build/module.min.js in your page will expose window.XDOMLS

usage

just init the client using the code below and then use localStorage as you normally would

// simple usage
var client = new XDOMLS('http://yourcdn.com/iframe.html');

client.ready(function(){
  client.sync()
})

// additional functionality (can be used with or without sync)
client.ready(function(){

  // client will automatically be assigned a persistent unique identifier
  console.log('Client ready, session details:',client.SESSION)

  // set a persistent value into the frame
  client.set('hello-perma','perma-value')

  // set a value that expires in 30s
  client.set('hello-temp','temp-value',30);

  // delete a value
  client.del('hello')

  // get all values from frame
  client.get_all(function(e,r){
    console.log(r)
  })

})

// instantiation options
new XDOMLS('http://www.taky.com/un/xdomls/iframe/build/index.html',{

  // prefix for all keys within the cross browser frame
  prefix: 'tracking'

  // console logging for client
  debug: true,

  // console logging for cross browser frame
  debug_frame: true,

  // shows iframe instead of applying styles to hide it
  show_frame: true,

  // keys to skip auto-syncing for
  sync_ignore_keys: [
    'private-key'
  ],

  // sync interval between window.top and cross browser frame
  sync_polling_ms: 100,

  // cross browser from element id
  frame_id: 'persistent-storage',

})

// defaults
{
  prefix: 'xd'
  debug: false
  debug_frame: false
  show_frame: false
  sync_ignore_keys: []
  sync_polling_ms: 100
  frame_id: '__xdomls'
}

see example usage in test/example/

tested in

• latest version of all major browsers
• latest version ios/safari

@todo:

• frame location.hash communication mechanism as a postMessage fallback

api

fn	args	description
set	key,val,[expires_secs=0],[cb]	set item into cross-domain storage, allows for optional expiration time
get	key,cb	retrieve item from cross-domain storage
get_all	[simple=true],cb	retrieve all items from cross-domain storage
del	key,[cb]	remove item from cross-domain storage
clear	[cb]	clears all items from xdomls and localStorage (besides the user's session/uuid)
get_expired	[simple=true],cb	retrieve list of any keys expired this session
session	[refresh=false],[cb]	get session information, reset session if refresh is true
sync	none	syncs top.localStorage and frame storage automatically