119 lines
4.1 KiB
JavaScript
119 lines
4.1 KiB
JavaScript
/* eslint-disable max-classes-per-file */
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import { basicAuth, bearerAuth, encodeBase64Url, topicShortUrl, topicUrlWs } from "./utils";
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const retryBackoffSeconds = [5, 10, 20, 30, 60, 120];
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export class ConnectionState {
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static Connected = "connected";
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static Connecting = "connecting";
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}
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/**
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* A connection contains a single WebSocket connection for one topic. It handles its connection
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* status itself, including reconnect attempts and backoff.
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*
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* Incoming messages and state changes are forwarded via listeners.
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*/
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class Connection {
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constructor(connectionId, subscriptionId, baseUrl, topic, user, since, onNotification, onStateChanged) {
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this.connectionId = connectionId;
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this.subscriptionId = subscriptionId;
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this.baseUrl = baseUrl;
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this.topic = topic;
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this.user = user;
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this.since = since;
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this.shortUrl = topicShortUrl(baseUrl, topic);
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this.onNotification = onNotification;
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this.onStateChanged = onStateChanged;
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this.ws = null;
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this.retryCount = 0;
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this.retryTimeout = null;
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}
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start() {
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// Don't fetch old messages; we do that as a poll() when adding a subscription;
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// we don't want to re-trigger the main view re-render potentially hundreds of times.
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const wsUrl = this.wsUrl();
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console.log(`[Connection, ${this.shortUrl}, ${this.connectionId}] Opening connection to ${wsUrl}`);
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this.ws = new WebSocket(wsUrl);
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this.ws.onopen = (event) => {
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console.log(`[Connection, ${this.shortUrl}, ${this.connectionId}] Connection established`, event);
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this.retryCount = 0;
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this.onStateChanged(this.subscriptionId, ConnectionState.Connected);
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};
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this.ws.onmessage = (event) => {
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console.log(`[Connection, ${this.shortUrl}, ${this.connectionId}] Message received from server: ${event.data}`);
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try {
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const data = JSON.parse(event.data);
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if (data.event === "open") {
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return;
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}
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const relevantAndValid = data.event === "message" && "id" in data && "time" in data && "message" in data;
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if (!relevantAndValid) {
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console.log(`[Connection, ${this.shortUrl}, ${this.connectionId}] Unexpected message. Ignoring.`);
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return;
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}
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this.since = data.id;
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this.onNotification(this.subscriptionId, data);
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} catch (e) {
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console.log(`[Connection, ${this.shortUrl}, ${this.connectionId}] Error handling message: ${e}`);
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}
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};
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this.ws.onclose = (event) => {
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if (event.wasClean) {
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console.log(
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`[Connection, ${this.shortUrl}, ${this.connectionId}] Connection closed cleanly, code=${event.code} reason=${event.reason}`
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);
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this.ws = null;
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} else {
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const retrySeconds = retryBackoffSeconds[Math.min(this.retryCount, retryBackoffSeconds.length - 1)];
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this.retryCount += 1;
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console.log(`[Connection, ${this.shortUrl}, ${this.connectionId}] Connection died, retrying in ${retrySeconds} seconds`);
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this.retryTimeout = setTimeout(() => this.start(), retrySeconds * 1000);
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this.onStateChanged(this.subscriptionId, ConnectionState.Connecting);
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}
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};
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this.ws.onerror = (event) => {
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console.log(`[Connection, ${this.shortUrl}, ${this.connectionId}] Error occurred: ${event}`, event);
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};
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}
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close() {
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console.log(`[Connection, ${this.shortUrl}, ${this.connectionId}] Closing connection`);
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const socket = this.ws;
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const { retryTimeout } = this;
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if (socket !== null) {
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socket.close();
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}
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if (retryTimeout !== null) {
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clearTimeout(retryTimeout);
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}
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this.retryTimeout = null;
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this.ws = null;
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}
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wsUrl() {
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const params = [];
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if (this.since) {
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params.push(`since=${this.since}`);
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}
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if (this.user) {
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params.push(`auth=${this.authParam()}`);
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}
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const wsUrl = topicUrlWs(this.baseUrl, this.topic);
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return params.length === 0 ? wsUrl : `${wsUrl}?${params.join("&")}`;
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}
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authParam() {
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if (this.user.password) {
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return encodeBase64Url(basicAuth(this.user.username, this.user.password));
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}
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return encodeBase64Url(bearerAuth(this.user.token));
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}
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}
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export default Connection;
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