cors-light
v1.0.1
Published
Secure, shared local storage across domains
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Readme
cors-light
Secure, shared local storage across domains.
Usage
Client
The client sends requests to a cors-light server to get, set, and unset key-values in the server's store.
<!doctype html>
<html>
<head>
<title>Client</title>
<meta charset="utf-8">
<script src="client.js"></script>
</head>
<body>
<!-- Should run on leftdomain.com/client.html -->
<script>
var client = new CorsLight.Client('http://centraldomain.com/server.html');
client.get('infos').then(function(result) {
// result.value contains the value for "infos"
})
.catch(function(err) {
// In case something went wrong
});
</script>
</body>
</html>Server
The server is responsible for centralized local storage and fielding requests from cors-light clients. The server is opened in a hidden <iframe> by each client.
<!doctype html>
<html>
<head>
<title>Server</title>
<meta charset="utf-8">
<script src="server.js"></script>
</head>
<body>
<!-- Should run on centraldomain.com/server.html -->
<script>
new CorsLight.Server('usage', {
// The key "infos" is accessible by only clients on leftdomain.com and rightdomain.com
infos: ['leftdomain.com', 'rightdomain.com']
});
</script>
</body>
</html>API
new CorsLight.Client(uri, [errorHandler])
Creates a new cors-light client where,
uri- a URI pointing to a page running a cors-light server.errorHandler(err)- an optional callback where errors that are not tied to particular requests will be funneled.
client.get(key, [callback])
Obtains a cross-domain store where,
key- the key of the requested store.callback(err, store)- an optional callback returning the store for the givenkey. When not present,client.get()will instead return a promise. If an error occurs, it will be placed inerr. Thestoreis an object with the following key/values,value- the stored value.expire- a timestamp indicating when this store is scheduled to expire,falseif it is not scheduled to expire, or not present when the store is piggy-backing a session.session- if this store is using a cookie-bound session for expiration, this will be present with an id for the session.
client.set(key, value, [ttl], [callback])
Sets a cross-domain store where,
key- the key of the store being set.value- the value to assign to the store.ttl- an optional time-to-live for the store, specified in milliseconds. If set to'session', the store will instead expire with the user's browser session. Iffalseor not specified, the store will be scheduled to expire.callback(err)- an optional callback to indicate success or failure of setting the store. When not present,client.set()will instead return a promise.
client.unset(key, [callback])
Unsets a cross-domain store where,
key- the key of the store being unset.callback(err)- an optional callback to indicate success or failure of unsetting the store. When not present,client.unset()will instead return a promise.
new CorsLight.Server([namespace], manifest)
Creates a new cors-light server where,
namespace- an optional string used to namespace storage associated with this server. Defaults to'cl'.manifest- an object where each key is a storage key name and each value is a hostname or array of hostnames that can access (set, get, and unset) that key. For example,{ username: ['trixel.io', 'altered.io'] }
Extras
This project is inspired by (and effectively forked from) the late XAuth, which pioneered the technique used in cors-light to create a client-server model by posting messages between iframes, backed by local storage. The original technique dates back to 2010.