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İlkin Presence göndərmək

Presence information is a core functionality of the XMPP protocol. It allows users to broadcast their availability status to others on the network. When communicating over XMPP, it is often necessary to send presence notifications to inform others (usually contacts in your roster) about your current status, such as whether you're online, offline, away, or busy. These presence updates help users know when they can interact with one another in real-time.

In XMPP, presence information is typically sent to all users in your roster by default, but it can also be targeted to specific individuals or groups. The presence status is represented by different states, such as:

  • Available: Indicates that the user is online and ready for communication.
  • Away: Shows that the user is online but currently idle or away from their device.
  • Do Not Disturb (DND): Signals that the user is online but does not want to be interrupted.
  • Offline: Indicates that the user is not connected to the XMPP server.

XMPP uses presence to manage resources when a user is logged in from multiple devices (e.g., desktop and mobile) and to route messages accordingly.

In Whixp, sending a presence message is straightforward and can be triggered once the XMPP stream is negotiated. After a successful connection and stream negotiation, the client can notify other users of its presence status by sending a presence stanza:

whixp.addEventHandler('streamNegotiated', (_) => whixp.sendPresence());

When you send a presence message, you can observe the log output generated by Whixp, showing both the sent and received presence stanzas. Here’s an example of what you might see in the log:

[Whixp] SEND: <presence/>
[Whixp] RECEIVED: <presence xml:lang='en' to='vsevolod@localhost/desktop' from='vsevolod@localhost/desktop' xmlns="jabber:client"><x xmlns='vcard-temp:x:update'/></presence>

In Whixp, you have the flexibility to send different types of presence messages depending on your current availability. This is done by specifying the presence type when sending the message.

For example, if you want to notify your contacts that you are "away", you can specify this status using the show attribute when calling the sendPresence() method:

whixp.addEventHandler(
    'streamNegotiated',
    (_) => whixp.sendPresence(show: 'away'),
  );

The result of the sent stanza can be shown in the outputs log:


[Whixp] SEND: <presence><show>away</show></presence>
[Whixp] RECEIVED: <presence xml:lang='en' to='vsevolod@localhost/desktop' from='vsevolod@localhost/desktop' xmlns="jabber:client"><x xmlns='vcard-temp:x:update'/><show>away</show></presence>

Detailed presence​

In Whixp, you can send more detailed presence messages by specifying various parameters such as the recipient, availability status, nickname, custom status messages, and priority. This flexibility allows you tailor your prseence notifications according to your needs.

whixp.sendPresence(
      to: JabberID('alyosha@localhost'),
      show: 'away',
      nick: 'vsevex',
      status: 'I am away',
      priority: 1,
);

Breakdown of parameters:​

  • to: This parameter specifies the recipient of the presence message. In this case, it’s sent to the Jabber ID of a specific user (alyosha@localhost). This allows you to target presence updates to particular contacts rather than broadcasting to everyone in your roster.
  • show: This indicates the user's current status. By setting it to away, you are informing the recipient that you are currently not at your device, but you are still online.
  • nick: This parameter sets the nickname to be displayed along with the presence message. This can be useful for users who have different display names or want to differentiate themselves in group chats or multi-user environments.
  • status: This custom status message provides additional context about your availability.
  • priority: The priority parameter determines the importance of the presence message. It allows the server to manage multiple presence messages from the same user (e.g., from different devices). A higher priority value indicates a more preferred presence status. In this case, a priority of 1 suggests that the user wants this presence to be recognized, but it can be adjusted depending on the user's needs.

Handler​

You can add a presence handler in Whixp to accept and process incoming presence stanzas according to your requirements. This functionality allows you to implement various features, such as filtering presence types, managing user availability based on the sender, or bypassing redundant presence messages sent by the server.

Here’s an example of how to implement a presence handler:

whixp.addEventHandler<Presence>('presence', (presence) {
    if (presence == null) return; // Check if the presence stanza is null
    final from = presence.from?.bare;  // Get the bare JID of the sender

    log('Presence from: $from');
  });
məlumat

In upcoming updates, Whixp will enhance its handling of presence information by automatically managing user availability based on roster information and handling necessary roster updates according to the presence types received. For now, however, you will need to manage this information manually within your application logic.