Channels

Channels are named streams. A client opens one WebSocket connection to Vask, then subscribes that connection to one or more channels.

Use the same channel names and SDK calls you would use with Pusher Channels. Connect to wss://wss.vask.dev/app/{app_key} and use your Vask app_key as the SDK key.

#Channel types

Type	Prefix	Auth required	Tracks members	Notes
Public	none	No	No	Any connected client with the `app_key` can subscribe.
Private	`private-`	Yes	No	Your app signs each subscription.
Presence	`presence-`	Yes	Yes	Like private channels, plus member roster and join/leave events.
Cache	`cache-`	No	No	Replays the last server-triggered event to new subscribers.
Private cache	`private-cache-`	Yes	No	Private channel behavior plus cache replay.
Presence cache	`presence-cache-`	Yes	Yes	Presence channel behavior plus cache replay.
Encrypted	`private-encrypted-`	Yes	No	Private channel behavior plus SDK-managed encryption.
Encrypted cache	`private-encrypted-cache-`	Yes	No	Encrypted channel behavior plus cache replay.

#Public channels

Public channels do not call your auth endpoint. Use them only for data that can be read by anyone who knows the channel name.

const pusher = new Pusher('app_key', {
    wsHost: 'wss.vask.dev',
    wsPort: 443,
    forceTLS: true,
    enabledTransports: ['ws', 'wss'],
});

const channel = pusher.subscribe('public-feed');
channel.bind('message.created', (event) => {
    console.log(event);
});

#Private channels

Private channels require a server-side authorization response. The SDK posts socket_id and channel_name to your auth endpoint, then sends the returned auth value in the pusher:subscribe frame.

const channel = pusher.subscribe('private-dashboard.42');

channel.bind('metric.updated', (event) => {
    console.log(event);
});

Your auth endpoint decides whether the current user can subscribe.

{
    "auth": "app_key:hmac_signature"
}

#Presence channels

Presence channels use the same authorization flow as private channels, but the response also includes JSON-encoded channel_data.

{
    "auth": "app_key:hmac_signature",
    "channel_data": "{\"user_id\":\"user-123\",\"user_info\":{\"name\":\"Ada\"}}"
}

The user_id is the identity Vask uses for the roster. If the same user has several tabs open, they count as one presence member.

const room = pusher.subscribe('presence-room.42');

room.bind('pusher:subscription_succeeded', (members) => {
    console.log(members);
});

room.bind('pusher:member_added', (member) => {
    console.log(member.id);
});

room.bind('pusher:member_removed', (member) => {
    console.log(member.id);
});

#Naming rules

Channel names should be stable ASCII strings. Keep names short and application scoped.

public-feed
private-user.123
presence-document.456
cache-market-data.BTCUSD
private-encrypted-chat.789

Do not put secrets in channel names. Private and presence channels enforce access through the auth signature, not through obscurity.

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