JSO - a Javascript OAuth Library

UPDATE March 20th 2013: I just commited JSO version 2.0, a redesigned library. It is only in beta state yet, but feel free to test it.

This library was written by Andreas Åkre Solberg (UNINETT AS) in March 2012.

• Read the blog of Andreas Åkre Solberg
• Follow Andreas Åkre Solberg on twitter
• Read more about UNINETT
• Contact address: mailto:andreas.solberg@uninett.no

It's intended use is for web applications (javascript) that connects to one or more APIs using OAuth 2.0.

Current status is that the library is not well tested, due to lack of known providers with support for OAuth 2.0

Be aware of the cross-domain policy limitiations of browser. Check out CORS, JSONP, or consider proxying the requests from the browser through your own webserver.

If you want to use JSO together with Phonegap to support OAuth 2.0 in a hybrid web application, you may want to read the

• JSO Phonegap Guide

Licence

UNINETT holds the copyright of the JSO library. The software can be used free of charge for both non-commercial and commercial projects.

The software is dual-licenced with The GNU Lesser General Public License, version 2.1 (LGPL-2.1) and version 3.0; meaning that you can select which of these two versions depending on your needs.

• http://opensource.org/licenses/lgpl-2.1
• http://opensource.org/licenses/LGPL-3.0

Features

• Implements OAuth 2.0 Implicit Flow. All you need is a single javascript file.
• Supports the bearer access token type.
• No server component needed.
• Adds a jQuery plugin extending the $.ajax() function with OAuth capabilities.
• Can handle multilple providers at once.
• Uses HTML 5.0 localStorage to cache Access Tokens. You do not need to implement a storage.
• Can prefetch all needed tokens with sufficient scopes, to start with, then tokens can be used for reqiests later. This way, you can be sure that you would not need to redirect anywhere in your business logic, because you would need to refresh an expired token.
• Excellent scope support.
• Caches and restores the hash, your application will not loose state when sending the user to the authorization endpoint.

Dependencies

JSO makes use of jQuery, mostly to plugin and make use of the $.ajax() function. If there is an interest for making JSO independent from jQuery, I can do that.

Browser support

JSO uses localStorage for caching tokens. localStorage is supported in Firefox 3.5+, Safari 4+, IE8+, and Chrome. For better compatibility use the localstorage library that is included in the example.

JSO uses JSON serialization functions (stringify and parse). These are supported in Firefox 3.5, Internet Explorer 8.0 and Chrome 3. For better compatibility use the JSON2.js library that also is included in the example.

Configure

First, you must configure your OAuth providers. You do that by calling jso_configure with a configuration object as a parameter.

The object is a key, value set of providers, where the providerID is an internal identifier of the provider that is used later, when doing protected calls.

In this example, we set the provider identifier to be facebook.

	jso_configure({
		"facebook": {
			client_id: "xxxxxxxxxx",
			redirect_uri: "http://localhost/~andreas/jso/",
			authorization: "https://www.facebook.com/dialog/oauth",
			presenttoken: "qs"
		}
	});

• client_id: The client idenfier of your client that as trusted by the provider. As JSO uses the implicit grant flow, there is now use for a
• redirect_uri: OPTIONAL (may be needed by the provider). The URI that the user will be redirected back to when completed. This shuold be the same URL that the page is presented on.
• presenttoken: OPTIONAL How to present the token with the protected calls. Values can be qs (in query string) or header (default; in authorization header).
• default_lifetime : OPTIONAL Seconds with default lifetime of an access token. If set to false, it means permanent.
• permanent_scope: A scope that indicates that the lifetime of the access token is infinite. (not yet tested.)
• isDefault: Some OAuth providers does not support the state parameter. When this parameter is missing, the consumer does not which provider that is sending the access_token. If you only provide one provider config, or set isDefault to true for one of them, the consumer will assume this is the provider that sent the token.
• scope: For providers that does not support state: If state was not provided, and default provider contains a scope parameter we assume this is the one requested... Set this as the same list of scopes that you provide to ensure_tokens.

The second optional parameter, options, of jso_configure(providerconfig, options) allows you to configure these global settings:

• debug: Default value is false. If you enable debugging, JSO will log a bunch of things to the console, using console.log - if not, JSO will not log anything.

Authorization

This OPTIONAL step involves an early ensurance that all neccessary access tokens have been retreived.

jso_ensureTokens can be used to force user authentication before you really need it; and the reason why you would typically do that is to make it easier to recover the state when you return. Typically if you need an OAuth token in the middle of a complex transaction it would be really difficult if the user is redirected away during that transaction, instead you can use jso_ensureTokens before starting with the transaction.

Using jso_ensureTokens is completely optional, and when you do not want to make sure that you have sufficient tokens before you really need it, then you can call $.oajax right away and it will redirect you for authenticationo - if needed.

By doing a call like this early in your code:

	// Make sure that you have 
	jso_ensureTokens({
		"facebook": ["read_stream"],
		"google": ["https://www.googleapis.com/auth/userinfo.profile"]
	});

the library will check its cached tokens, and if it does not have the specified tokens/scopes, it will start a new authorization process.

When this code is completed, you know that you have valid tokens for your use cases.

The jso_ensureTokens function takes an object as input, with the providerids as keys, and the values are eigther false or an array of required scopes. A value of false mean that we do not care about scopes, but we want a valid token.

OAuth protected data requests

To get data, you eigther use the jso_getToken("facebook") function, that returns a valid access token (or null), or you may use the $.oajax() function.

The $.oajax() function works very similar to $.ajax() (see documentation), actually the settings parameters are bypassed to the real $.ajax() function.

In addition to the settings properties allowed by $.ajax(), these properties are allowed:

• jso_provider: The providerid of the OAuth provider to use.
• jso_allowia: Allow userinteraction? If you have prepared the tokens, using jso_ensureTokens() you might set this value to false (default) and it will trow an exception instead of starting a new authorization process.
• jso_scopes: If this specific call requires one or more scopes, provide it here. It will be used to find a suitable token, if multiple exists.

Here is an example of retrieving the Facebook newsstream using OAuth:

	$.oajax({
		url: "https://graph.facebook.com/me/home",
		jso_provider: "facebook",
		jso_scopes: ["read_stream"],
		jso_allowia: true,
		dataType: 'json',
		success: function(data) {
			console.log("Response (facebook):");
			console.log(data);
		}
	});

jQuery or not jQuery

If you load jQuery before the JSO library, it will discover and add the $.oajax function. However, loading jQuery is optional, and if you do not load jQuery JSO will not complain, but neigther will if offer the easy to use $.oajax function.

If you do not use jQuery, you probably want to use the jso_getToken(providerid, scopes) function.

	var accesstoken = jso_getToken("facebook", "read_stream");

	var authzheader = "Authorization: Authorization " + accesstoken;
	// Perform the Cross site AJAX request using this custom header with your
	// preferred AJAX library.

Using JSO With Phonegap

Normal use of JSO involves JSO redirecting to the OAuth authorization endpoint for authentication and authorization, then the user is redirected back to the callback url where JSO autoamtically inspects the hash for an access token, and caches it.

When using JSO with phonegap (or similar libraries), you would not perform a normal redirect, but instead open a childbrowser. And when the user returns you would need to tell JSO what URL the childbrowser ended up on.

Register a custom URL redirect handler

	jso_registerRedirectHandler(function(url) {
		console.log("About to redirect the user to ", url);
		console.log("Instead we can do whatever we want, such as opening a child browser");

		// Open a child browser or similar.
	});

Please help! I have not used phonegap my self, and if someone could provide exact code examples for use with phonegap I would appreciate that.

Tell JSO about the return URL

Use the following function providing the url of the callback page, including the parameters in the hash: jso_checkfortoken(providerid, url)

The provided parameters might be like this:

• jso_checkfortoken('facebook', 'https://yourservice.org/callback#accesstoken=lsdkfjldkfj')

Some convenient debugging functions

For debugging, open the javascript console. And you might type:

	jso_dump();

to list all cached tokens, and

	jso_wipe();

to remove all tokens.

Upgrade

This section will contain useful information if you have been using JSO already, and would like to update to the latest version. API and configuration changes will be listed here.