const sourcesByUrl = {};const sourcesByPort = {}; class Source { constructor(url) { this.url = url; this.eventSource = new EventSource(url); this.listening = {}; this.clients = []; this.listen('open'); this.listen('close'); this.listen('logout'); this.listen('notification-count'); this.listen('stopwatches'); this.listen('error'); } register(port) { if (this.clients.includes(port)) return; this.clients.push(port); port.postMessage({ type: 'status', message: `registered to ${this.url}`, }); } deregister(port) { const portIdx = this.clients.indexOf(port); if (portIdx === -1) { return this.clients.length; } this.clients.splice(portIdx, 1); return this.clients.length; } close() { if (!this.eventSource) return; this.eventSource.close(); this.eventSource = null; } listen(eventType) { if (this.listening[eventType]) return; this.listening[eventType] = true; this.eventSource.addEventListener(eventType, (event) => { this.notifyClients({ type: eventType, data: event.data, }); }); } notifyClients(event) { for (const client of this.clients) { client.postMessage(event); } } status(port) { port.postMessage({ type: 'status', message: `url: ${this.url} readyState: ${this.eventSource.readyState}`, }); }} self.addEventListener('connect', (e) => { for (const port of e.ports) { port.addEventListener('message', (event) => { if (!self.EventSource) { // some browsers (like PaleMoon, Firefox<53) don't support EventSource in SharedWorkerGlobalScope. // this event handler needs EventSource when doing "new Source(url)", so just post a message back to the caller, // in case the caller would like to use a fallback method to do its work. port.postMessage({type: 'no-event-source'}); return; } if (event.data.type === 'start') { const url = event.data.url; if (sourcesByUrl[url]) { // we have a Source registered to this url const source = sourcesByUrl[url]; source.register(port); sourcesByPort[port] = source; return; } let source = sourcesByPort[port]; if (source) { if (source.eventSource && source.url === url) return; // How this has happened I don't understand... // deregister from that source const count = source.deregister(port); // Clean-up if (count === 0) { source.close(); sourcesByUrl[source.url] = null; } } // Create a new Source source = new Source(url); source.register(port); sourcesByUrl[url] = source; sourcesByPort[port] = source; } else if (event.data.type === 'listen') { const source = sourcesByPort[port]; source.listen(event.data.eventType); } else if (event.data.type === 'close') { const source = sourcesByPort[port]; if (!source) return; const count = source.deregister(port); if (count === 0) { source.close(); sourcesByUrl[source.url] = null; sourcesByPort[port] = null; } } else if (event.data.type === 'status') { const source = sourcesByPort[port]; if (!source) { port.postMessage({ type: 'status', message: 'not connected', }); return; } source.status(port); } else { // just send it back port.postMessage({ type: 'error', message: `received but don't know how to handle: ${event.data}`, }); } }); port.start(); }});
const sourcesByUrl = {};
const sourcesByPort = {};
class Source {
constructor(url) {
this.url = url;
this.eventSource = new EventSource(url);
this.listening = {};
this.clients = [];
this.listen('open');
this.listen('close');
this.listen('logout');
this.listen('notification-count');
this.listen('stopwatches');
this.listen('error');
}
register(port) {
if (this.clients.includes(port)) return;
this.clients.push(port);
port.postMessage({
type: 'status',
message: `registered to ${this.url}`,
});
}
deregister(port) {
const portIdx = this.clients.indexOf(port);
if (portIdx === -1) {
return this.clients.length;
}
this.clients.splice(portIdx, 1);
return this.clients.length;
}
close() {
if (!this.eventSource) return;
this.eventSource.close();
this.eventSource = null;
}
listen(eventType) {
if (this.listening[eventType]) return;
this.listening[eventType] = true;
this.eventSource.addEventListener(eventType, (event) => {
this.notifyClients({
type: eventType,
data: event.data,
});
});
}
notifyClients(event) {
for (const client of this.clients) {
client.postMessage(event);
}
}
status(port) {
port.postMessage({
type: 'status',
message: `url: ${this.url} readyState: ${this.eventSource.readyState}`,
});
}
}
self.addEventListener('connect', (e) => {
for (const port of e.ports) {
port.addEventListener('message', (event) => {
if (!self.EventSource) {
// some browsers (like PaleMoon, Firefox<53) don't support EventSource in SharedWorkerGlobalScope.
// this event handler needs EventSource when doing "new Source(url)", so just post a message back to the caller,
// in case the caller would like to use a fallback method to do its work.
port.postMessage({type: 'no-event-source'});
return;
}
if (event.data.type === 'start') {
const url = event.data.url;
if (sourcesByUrl[url]) {
// we have a Source registered to this url
const source = sourcesByUrl[url];
source.register(port);
sourcesByPort[port] = source;
return;
}
let source = sourcesByPort[port];
if (source) {
if (source.eventSource && source.url === url) return;
// How this has happened I don't understand...
// deregister from that source
const count = source.deregister(port);
// Clean-up
if (count === 0) {
source.close();
sourcesByUrl[source.url] = null;
}
}
// Create a new Source
source = new Source(url);
source.register(port);
sourcesByUrl[url] = source;
sourcesByPort[port] = source;
} else if (event.data.type === 'listen') {
const source = sourcesByPort[port];
source.listen(event.data.eventType);
} else if (event.data.type === 'close') {
const source = sourcesByPort[port];
if (!source) return;
const count = source.deregister(port);
if (count === 0) {
source.close();
sourcesByUrl[source.url] = null;
sourcesByPort[port] = null;
}
} else if (event.data.type === 'status') {
const source = sourcesByPort[port];
if (!source) {
port.postMessage({
type: 'status',
message: 'not connected',
});
return;
}
source.status(port);
} else {
// just send it back
port.postMessage({
type: 'error',
message: `received but don't know how to handle: ${event.data}`,
});
}
});
port.start();
}
});