WebSocket
Tvheadend has a WebSocket interface on port 9981. It is used by the UI to provide 'live' actions and updates, avoiding the need to refresh the screen.
Example Code
The example below creates a WebSocket connection to the Tvheadend server and listens for updates.
<!DOCTYPE html>
<html lang="">
<head>
<meta charset="utf-8">
<title>Websocket Test</title>
<script>
let socket = new WebSocket("ws://192.168.0.1:9981/comet/ws");
socket.onmessage = function(event) {
let message = event.data;
let messageElem = document.createElement('div');
messageElem.textContent = message;
document.getElementById('messages').prepend(messageElem);
}
</script>
</head>
<body>
<header></header>
<main>
<div id="messages"></div>
</main>
<footer></footer>
</body>
</html>Output
Tvheadend transmits messages on the Websocket interface asynchronously, when either an event occurs or in some cases at scheduled intervals. The output format is JSON.
Each message contains a key "messages" whose value is an array of message objects. Each message object contains a key "notificationClass" which specifies the source of the message, and a series of message-specific key-value pairs.
Object Changes
Some "notificationClass" messages may optionally contain one or more of the following arrays: "create", "change" and "delete". When present, these arrays will contain lists of UUIDs that have been created, modified or deleted as part of the scope of the current notification.
When a "notificationClass" is "epg", the arrays described above will contain EventIds rather than UUIDs and the 'update" array will be present rather than "change". Two additional arrays ('dvr_delete' and 'dvr_update') may also be present to indicate a change in recording status of the EPG event.
With regards to "create" and "change"/"update" notifications, the UUID/EventID will need to be explicitly fetched to obtain the new object property values.
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