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