class Subscriber {

constructor(sseClient, allTargetsAuthorized, authorizedTargets, topics, lastEventId) {

this.sseClient = sseClient;

this.allTargetsAuthorized = allTargetsAuthorized;

this.authorizedTargets = authorizedTargets;

this.topics = topics; // URI templates (RFC 6570)

this.lastEventId = lastEventId;

}

toValue() {

return {

topics: this.topics.map(t => t.toString()),

ip: this.sseClient.req.socket.localAddress,

all: this.allTargetsAuthorized,

last: this.lastEventId,

authorized: this.authorizedTargets

}

}

send(update) {

this.sseClient.send(update.event);

}

async sendAsync(update) {

this.sseClient.send(update.event);

}

closeConnection() {

// Ends the response.

this.sseClient.close();

// Manually closes the connection.

this.sseClient.res.emit('close');

}

canReceive(update) {

return this.isAuthorized(update) && this.isSubscribed(update);

}

isAuthorized(update) {

// Check if the subscriber's JWT claims a target '*' and/or wants public updates.

if (this.allTargetsAuthorized || this.authorizedTargets.length === 0) {

// Either :

// - the subscriber is authorized to receive updates destined for all targets

// - the subscriber is authorized to receive public updates

// => Allow all updates.

return true;

}

if (update.targets === null) {

// The update can be sent to all subscribers.

return true;

}

return this.authorizedTargets.some(target => update.targets.includes(target));

}

isSubscribed(update) {

for (const subscriberTopic of this.topics) {

for (const updateTopic of update.topics) {

if (subscriberTopic.test(updateTopic)) {

return true;

}

}

}

return false;

}

}

module.exports = Subscriber;