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import { getLogger } from '../logging';
import { PendingRequest } from './PendingRequest';
import {
isErrorResponse,
isOkResponse,
isPushMessage,
IXtextWebRequest,
} from './xtextMessages';
const XTEXT_SUBPROTOCOL_V1 = 'tools.refinery.language.web.xtext.v1';
const WEBSOCKET_CLOSE_OK = 1000;
const RECONNECT_DELAY_MS = 1000;
const log = getLogger('XtextWebSocketClient');
type ReconnectHandler = () => void;
type PushHandler = (resourceId: string, stateId: string, service: string, data: unknown) => void;
export class XtextWebSocketClient {
nextMessageId = 0;
closing = false;
connection!: WebSocket;
pendingRequests = new Map<string, PendingRequest>();
onReconnect: ReconnectHandler;
onPush: PushHandler;
reconnectTimeout: NodeJS.Timeout | null = null;
constructor(onReconnect: ReconnectHandler, onPush: PushHandler) {
this.onReconnect = onReconnect;
this.onPush = onPush;
this.reconnect();
}
get isOpen(): boolean {
return this.connection.readyState === WebSocket.OPEN;
}
private reconnect() {
this.reconnectTimeout = null;
const webSocketServer = window.origin.replace(/^http/, 'ws');
const webSocketUrl = `${webSocketServer}/xtext-service`;
this.connection = new WebSocket(webSocketUrl, XTEXT_SUBPROTOCOL_V1);
this.connection.addEventListener('open', () => {
if (this.connection.protocol !== XTEXT_SUBPROTOCOL_V1) {
log.error('Unknown subprotocol', this.connection.protocol, 'selected by server');
this.forceReconnectDueToError();
return;
}
log.info('Connected to xtext web services');
this.onReconnect();
});
this.connection.addEventListener('error', (event) => {
log.error('Unexpected websocket error', event);
this.forceReconnectDueToError();
});
this.connection.addEventListener('message', (event) => {
this.handleMessage(event.data);
});
this.connection.addEventListener('close', (event) => {
if (!this.closing || event.code !== WEBSOCKET_CLOSE_OK) {
log.error('Websocket closed undexpectedly', event.code, event.reason);
}
this.cleanupAndMaybeReconnect();
});
}
private cleanupAndMaybeReconnect() {
this.pendingRequests.forEach((pendingRequest) => {
pendingRequest.reject(new Error('Websocket closed'));
});
this.pendingRequests.clear();
if (this.closing) {
return;
}
if (this.reconnectTimeout !== null) {
clearTimeout(this.reconnectTimeout);
}
this.reconnectTimeout = setTimeout(() => {
log.info('Attempting to reconnect websocket');
this.reconnect();
}, RECONNECT_DELAY_MS);
}
public forceReconnectDueToError(): void {
this.closeConnection();
this.cleanupAndMaybeReconnect();
}
send(request: unknown): Promise<unknown> {
if (!this.isOpen) {
throw new Error('Connection is not open');
}
const messageId = this.nextMessageId.toString(16);
if (messageId in this.pendingRequests) {
log.error('Message id wraparound still pending', messageId);
this.rejectRequest(messageId, new Error('Message id wraparound'));
}
if (this.nextMessageId >= Number.MAX_SAFE_INTEGER) {
this.nextMessageId = 0;
} else {
this.nextMessageId += 1;
}
const message = JSON.stringify({
id: messageId,
request,
} as IXtextWebRequest);
return new Promise((resolve, reject) => {
this.connection.send(message);
this.pendingRequests.set(messageId, new PendingRequest(resolve, reject));
});
}
private handleMessage(messageStr: unknown) {
if (typeof messageStr !== 'string') {
log.error('Unexpected binary message', messageStr);
this.forceReconnectDueToError();
return;
}
log.trace('Incoming websocket message', messageStr);
let message: unknown;
try {
message = JSON.parse(messageStr);
} catch (error) {
log.error('Json parse error', error);
this.forceReconnectDueToError();
return;
}
if (isOkResponse(message)) {
this.resolveRequest(message.id, message.response);
} else if (isErrorResponse(message)) {
this.rejectRequest(message.id, new Error(`${message.error} error: ${message.message}`));
if (message.error === 'server') {
log.error('Reconnecting due to server error: ', message.message);
this.forceReconnectDueToError();
}
} else if (isPushMessage(message)) {
this.onPush(message.resource, message.stateId, message.service, message.push);
} else {
log.error('Unexpected websocket message', message);
this.forceReconnectDueToError();
}
}
private resolveRequest(messageId: string, value: unknown) {
const pendingRequest = this.pendingRequests.get(messageId);
this.pendingRequests.delete(messageId);
if (pendingRequest) {
pendingRequest.resolve(value);
return;
}
log.error('Trying to resolve unknown request', messageId, 'with', value);
}
private rejectRequest(messageId: string, reason?: unknown) {
const pendingRequest = this.pendingRequests.get(messageId);
this.pendingRequests.delete(messageId);
if (pendingRequest) {
pendingRequest.reject(reason);
return;
}
log.error('Trying to reject unknown request', messageId, 'with', reason);
}
private closeConnection() {
if (this.connection && this.connection.readyState !== WebSocket.CLOSING
&& this.connection.readyState !== WebSocket.CLOSED) {
log.info('Closing websocket connection');
this.connection.close();
}
}
close(): void {
this.closing = true;
this.closeConnection();
}
}
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