PushMessageData

The PushMessageData interface of the Push API provides methods which let you retrieve the push data sent by a server in various formats.

Unlike the similar methods in the Fetch API, which only allow the method to be invoked once, these methods can be called multiple times.

Properties

None.

Methods

PushMessageData.arrayBuffer()

Extracts the data as an ArrayBuffer object.

PushMessageData.blob()

Extracts the data as a Blob object.

PushMessageData.json()

Extracts the data as a JSON object.

PushMessageData.text()

Extracts the data as a plain text string.

Examples

In our Push API Demo, we send JSON objects via push messages from our server by first converting them to strings via JSON.stringify() (see server.js example):

webPush.sendNotification(subscriber[2], 200, obj.key, JSON.stringify({
  action: 'chatMsg',
  name: obj.name,
  msg: obj.msg
}));

When the message reaches the service worker, we convert the data back to a JSON object using PushMessageData.json() before working out what to do with it next:

self.addEventListener('push', function(event) {
  var obj = event.data.json();

  if(obj.action === 'subscribe' || obj.action === 'unsubscribe') {
    fireNotification(obj, event);
    port.postMessage(obj);
  } else if(obj.action === 'init' || obj.action === 'chatMsg') {
    port.postMessage(obj);
  }
});

Specifications

Specification	Status	Comment
Push API The definition of 'PushMessageData' in that specification.	Working Draft	Initial definition.

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