PushSubscription.getKey

The getKey() method of the PushSubscription interface returns an ArrayBuffer representing a client public key, which can then be sent to a server and used in encrypting push message data.

Syntax

​var key = subscription.getKey(method);

Parameters

method

The encryption method used to generate the client public key. p256dh is currently the only option. The method value can be:

• p256dh: an Elliptic curve Diffie–Hellman public key on the P-256 curve (that is, the NIST secp256r1 elliptic curve). The resulting key is an uncompressed point in ANSI X9.62 format.

Returns

An ArrayBuffer.

Example

In our Push API demo, we call getKey('p256dh') and PushSubscription.endpoint to get the necessary credentials we need to encrypt push message data, and send push messages from our server to specific subscribers.

reg.pushManager.getSubscription()  
  .then(function(subscription) {  
  // Enable any UI which subscribes / unsubscribes from  
  // push messages.  
 
  subBtn.disabled = false;

  if (!subscription) {  
    console.log('Not yet subscribed to Push')
    // We aren't subscribed to push, so set UI  
    // to allow the user to enable push  
    return;  
  }

  // Set your UI to show they have subscribed for  
  // push messages  
  subBtn.textContent = 'Unsubscribe from Push Messaging';  
  isPushEnabled = true;  
        
  // initialize status, which includes setting UI elements for subscribed status
  // and updating Subscribers list via push
  var endpoint = subscription.endpoint;
  var key = subscription.getKey('p256dh');

    ...

Specifications

Specification	Status	Comment
Push API	Working Draft	This is the Push API spec, but note that getKey() is not currently specified in here. It is currently Firefox-only experimental.

Browser Compatibility

• [1] Push (and Service Workers) have been disabled in the Firefox 45 Extended Support Release (ESR.)
• [2] Push has been enabled by default on Firefox for Android version 48.

See also

• Using the Push API