hello.js

A client-side JavaScript SDK for authenticating with OAuth2 (and OAuth1 with a oauth proxy) web services and querying their REST APIs. HelloJS standardizes paths and responses to common APIs like Google Data Services, Facebook Graph and Windows Live Connect. It's modular, so that list is growing. No more spaghetti code!

E.g.

Try out the next version

The next version is a modern rewrite of hellojs, please support this development in the v2 branch.

npm i hellojs@next

Features

Here are some more demos...

• Items marked with a ✓ are fully working and can be tested here.
• Items marked with a ✗ aren't provided by the provider at this time.
• Blank items are a work in progress, but there is good evidence that they can be done.
• I have no knowledge of anything unlisted and would appreciate input.

Install

Download: HelloJS | HelloJS (minified)

Compiled source, which combines all of the modules, can be obtained from GitHub, and source files can be found in Source.

Note: Some services require OAuth1 or server-side OAuth2 authorization. In such cases, HelloJS communicates with an OAuth Proxy.

NPM

npm i hellojs

At the present time only the bundled files in the /dist/hello.* support CommonJS. e.g. let hello = require('hellojs/dist/hello.all.js').

Bower

bower install hello

The Bower package shall install the aforementioned "/src" and "/dist" directories. The "/src" directory provides individual modules which can be packaged as desired.

Help & Support

• GitHub for reporting bugs and feature requests.
• Gitter to reach out for help.
• Stack Overflow use tag hello.js
• Slides by Freddy Harris

Quick Start

Quick start shows you how to go from zero to loading in the name and picture of a user, like in the demo above.

• Register your app domain
• Include hello.js script
• Create the sign-in buttons
• Setup listener for login and retrieve user info
• Initiate the client_ids and all listeners

1. Register

Register your application with at least one of the following networks. Ensure you register the correct domain as they can be quite picky.

• Facebook
• Windows Live
• Google+

2. Include Hello.js script in your page

<script src="./dist/hello.all.js"></script>

3. Create the sign-in buttons

Just add onclick events to call hello(network).login(). Style your buttons as you like; I've used zocial css, but there are many other icon sets and fonts.

<button onclick="hello('windows').login()">windows</button>

4. Add listeners for the user login

Let's define a simple function, which will load a user profile into the page after they sign in and on subsequent page refreshes. Below is our event listener which will listen for a change in the authentication event and make an API call for data.

hello.on('auth.login', function(auth) {

	// Call user information, for the given network
	hello(auth.network).api('me').then(function(r) {
		// Inject it into the container
		var label = document.getElementById('profile_' + auth.network);
		if (!label) {
			label = document.createElement('div');
			label.id = 'profile_' + auth.network;
			document.getElementById('profile').appendChild(label);
		}
		label.innerHTML = '<img src="' + r.thumbnail + '" /> Hey ' + r.name;
	});
});

5. Configure hello.js with your client IDs and initiate all listeners

Now let's wire it up with our registration detail obtained in step 1. By passing a [key:value, ...] list into the hello.init function. e.g....

hello.init({
	facebook: FACEBOOK_CLIENT_ID,
	windows: WINDOWS_CLIENT_ID,
	google: GOOGLE_CLIENT_ID
}, {redirect_uri: 'redirect.html'});

That's it. The code above actually powers the demo at the start so, no excuses.

Core Methods

hello.init()

Initiate the environment. And add the application credentials.

hello.init({facebook: id, windows: id, google: id, ... })

Example:

hello.init({
	facebook: '359288236870',
	windows: '000000004403AD10'
});

hello.login()

If a network string is provided: A consent window to authenticate with that network will be initiated. Else if no network is provided a prompt to select one of the networks will open. A callback will be executed if the user authenticates and or cancels the authentication flow.

hello.login([network] [, options] [, callback()])

Examples:

hello('facebook').login().then(function() {
	alert('You are signed in to Facebook');
}, function(e) {
	alert('Signin error: ' + e.error.message);
});

hello.logout()

Remove all sessions or individual sessions.

hello.logout([network] [, options] [, callback()])

Example:

hello('facebook').logout().then(function() {
	alert('Signed out');
}, function(e) {
	alert('Signed out error: ' + e.error.message);
});

hello.getAuthResponse()

Get the current status of the session. This is a synchronous request and does not validate any session cookies which may have expired.

hello.getAuthResponse(network)

Examples:

var online = function(session) {
	var currentTime = (new Date()).getTime() / 1000;
	return session && session.access_token && session.expires > currentTime;
};

var fb = hello('facebook').getAuthResponse();
var wl = hello('windows').getAuthResponse();

alert((online(fb) ? 'Signed' : 'Not signed') + ' into Facebook, ' + (online(wl) ? 'Signed' : 'Not signed') + ' into Windows Live');

hello.api()

Make calls to the API for getting and posting data.

hello.api([path], [method], [data], [callback(json)])

hello.api([path], [method], [data], [callback(json)]).then(successHandler, errorHandler)

Examples:

hello('facebook').api('me').then(function(json) {
	alert('Your name is ' + json.name);
}, function(e) {
	alert('Whoops! ' + e.error.message);
});

Event Subscription

Please see demo of the global events.

hello.on()

Bind a callback to an event. An event may be triggered by a change in user state or a change in some detail.

hello.on(event, callback)

Example:

var sessionStart = function() {
	alert('Session has started');
};
hello.on('auth.login', sessionStart);

hello.off()

Remove a callback. Both event name and function must exist.

hello.off(event, callback)

hello.off('auth.login', sessionStart);

Concepts

Pagination, Limit and Next Page

Responses which are a subset of the total results should provide a response.paging.next property. This can be plugged back into hello.api in order to get the next page of results.

In the example below the function paginationExample() is initially called with me/friends. Subsequent calls take the path from resp.paging.next.

function paginationExample(path) {
	hello('facebook')
		.api(path, {limit: 1})
		.then(
			function callback(resp) {
				if (resp.paging && resp.paging.next) {
					if (confirm('Got friend ' + resp.data[0].name + '. Get another?')) {
						// Call the API again but with the 'resp.paging.next` path
						paginationExample(resp.paging.next);
					}
				}
				else {
					alert('Got friend ' + resp.data[0].name);
				}
			},
			function() {
				alert('Whoops!');
			}
		);
}

paginationExample('me/friends');

Scope

The scope property defines which privileges an app requires from a network provider. The scope can be defined globally for a session through hello.init(object, {scope: 'string'}), or at the point of triggering the auth flow e.g. hello('network').login({scope: 'string'}); An app can specify multiple scopes, separated by commas - as in the example below.

hello('facebook').login({
    scope: 'friends, photos, publish'
});

Scopes are tightly coupled with API requests. Unauthorized error response from an endpoint will occur if the scope privileges have not been granted. Use the hello.api reference table to explore the API and scopes.

It's considered good practice to limit the use of scopes. The more unnessary privileges you ask for the more likely users are going to drop off. If your app has many different sections, consider re-authorizing the user with different privileges as they go.

HelloJS modules standardises popular scope names. However you can always use proprietary scopes, e.g. to access google spreadsheets: hello('google').login({scope: 'https://spreadsheets.google.com/feeds'});

Redirect Page

Providers of the OAuth1/2 authorization flow must respect a Redirect URI parameter in the authorization request (also known as a Callback URL). E.g. ...&redirect_uri=http://mydomain.com/redirect.html&...

The redirect_uri is always a full URL. It must point to a Redirect document which will process the authorization response and set user session data. In order for an application to communicate with this document and set the session data, the origin of the document must match that of the application - this restriction is known as the same-origin security policy.

A successful authorisation response will append the user credentials to the Redirect URI. e.g. ?access_token=12312&expires_in=3600. The Redirect document is responsible for interpreting the request and setting the session data.

Create a Redirect Page and URI

In HelloJS the default value of redirect_uri is the current page. However its recommended that you explicitly set the redirect_uri to a dedicated page with minimal UI and page weight.

Create an HTML page on your site which will be your redirect document. Include the HelloJS script e.g...

<!doctype html>
<script src="./hello.js"></script>;

Do add css animations incase there is a wait. View Source on ./redirect.html for an example.

Then within your application script where you initiate HelloJS, define the Redirect URI to point to this page. e.g.

hello.init({
	facebook:client_id
}, {
	redirect_uri: '/redirect.html'
});

Please note: The redirect_uri example above in hello.init is relative, it will be turned into an absolute path by HelloJS before being used.

Error Handling

Errors are returned i.e. hello.api([path]).then(null, [*errorHandler*]) - alternatively hello.api([path], [*handleSuccessOrError*]).

The Promise response standardizes the binding of error handlers.

Error Object

The first parameter of a failed request to the errorHandler may be either boolean (false) or be an Error Object...

Extending the services

Services are added to HelloJS as "modules" for more information about creating your own modules and examples, go to Modules

OAuth Proxy

For providers which support only OAuth1 or OAuth2 with Explicit Grant, the authentication flow needs to be signed with a secret key that may not be exposed in the browser. HelloJS gets round this problem by the use of an intermediary webservice defined by oauth_proxy. This service looks up the secret from a database and performs the handshake required to provision an access_token. In the case of OAuth1, the webservice also signs subsequent API requests.

Quick start: Register your Client ID and secret at the OAuth Proxy service, Register your App

The default proxy service is https://auth-server.herokuapp.com/. Developers may add their own network registration Client ID and secret to this service in order to get up and running. Alternatively recreate this service with node-oauth-shim. Then override the default oauth_proxy in HelloJS client script in hello.init, like so...

hello.init(
	CLIENT_IDS,
	{
		oauth_proxy: 'https://auth-server.herokuapp.com/proxy'
	}
)

Enforce Explicit Grant

Enforcing the OAuth2 Explicit Grant is done by setting response_type=code in hello.login options - or globally in hello.init options. E.g...

hello(network).login({
	response_type: 'code'
});

Refresh Access Token

Access tokens provided by services are generally short lived - typically 1 hour. Some providers allow for the token to be refreshed in the background after expiry.

Unlike Implicit grant; Explicit grant may return the refresh_token. HelloJS honors the OAuth2 refresh_token, and will also request a new access_token once it has expired.

Bulletproof Requests

A good way to design your app is to trigger requests through a user action, you can then test for a valid access token prior to making the API request with a potentially expired token.

var google = hello('google');
// Set force to false, to avoid triggering the OAuth flow if there is an unexpired access_token available.
google.login({force: false}).then(function() {
	google.api('me').then(handler);
});

Promises A+

The response from the async methods hello.login, hello.logout and hello.api return a thenable method which is Promise A+ compatible.

For a demo, or, if you're bundling up the library from src/* files, then please checkout Promises

Browser Support

HelloJS targets all modern browsers.

Polyfills are included in src/hello.polyfill.js this is to bring older browsers upto date. If you're using the resources located in dist/ this is already bundled in. But if you're building from source you might like to first determine whether these polyfills are required, or if you're already supporting them etc...

PhoneGap Support

HelloJS can also be run on PhoneGap applications. Checkout the demo hellojs-phonegap-demo

Chrome Apps

Demo hellojs-chromeapp-demo

HelloJS module src/hello.chromeapp.js (also bundled in dist/*) shims the library to support the unique API's of the Chrome App environment (or Chrome Extension).

Chrome manifest.json prerequisites

The manifest.json file must have the following permissions...

	"permissions": [
	    "identity",
	    "storage",
	    "https://*/"
	],

Credits

HelloJS relies on these fantastic services for it's development and deployment, without which it would still be kicking around in a cave - not evolving very fast.

• BrowserStack for providing a means to test across multiple devices.
• Github for maintaining the repo and issue tracking.
• Travis for providing fantastic continuous integration.
• ... and others I've forgotten to mention

Can I contribute?

Yes, yes you can. In fact this isn't really free software, it comes with bugs and documentation errors. Moreover it tracks third party API's which just won't sit still. And it's intended for everyone to understand, so if you dont understand something then it's not fulfilling it's goal.

... otherwise give it a star.

Changing Code?

Ensure you setup and test your code on a variety of browsers.

# Using Node.js on your dev environment
# cd into the project root and install dev dependencies
npm install -l

# Install the grunt CLI (if you haven't already)
sudo npm install -g grunt-cli

# Run the tests
grunt test

# Run the tests in the browser...

# 1. In project root create local web server e.g.
python -m SimpleHTTPServer

# 2. Then open the following URL in your web browser:
# http://localhost:8000/tests/specs/index.html