✨ Add ws client with connect and disconnect interface

elements/lisk-api-client/package.json

@@ -38,8 +38,10 @@
 	"dependencies": {
 		"@liskhq/lisk-codec": "^0.1.0-alpha.0",
 		"@liskhq/lisk-cryptography": "^3.0.0-alpha.0",
+		"isomorphic-ws": "4.0.1",
 		"pm2-axon": "4.0.0",
-		"pm2-axon-rpc": "0.6.0"
+		"pm2-axon-rpc": "0.6.0",
+		"ws": "7.4.0"
 	},
 	"devDependencies": {
 		"@liskhq/lisk-chain": "^0.2.0-alpha.2",

elements/lisk-api-client/src/create_ws_client.ts

@@ -0,0 +1,26 @@
+/*
+ * Copyright © 2020 Lisk Foundation
+ *
+ * See the LICENSE file at the top-level directory of this distribution
+ * for licensing information.
+ *
+ * Unless otherwise agreed in a custom licensing agreement with the Lisk Foundation,
+ * no part of this software, including this file, may be copied, modified,
+ * propagated, or distributed except according to the terms contained in the
+ * LICENSE file.
+ *
+ * Removal or modification of this copyright notice is prohibited.
+ *
+ */
+
+import { WSClient } from './ws_client';
+
+export const createWSClient = async (url: string, autoConnect = true): Promise<WSClient> => {
+	const client = new WSClient(url);
+
+	if (autoConnect) {
+		await client.connect();
+	}
+
+	return client;
+};

elements/lisk-api-client/src/index.ts

@@ -12,6 +12,7 @@
  * Removal or modification of this copyright notice is prohibited.
  *
  */
-export { createWSClient } from './ws_client';
+
 export { createClient } from './client';
 export { createAPIClient } from './create_api_client';
+export { createWSClient } from './create_ws_client';

elements/lisk-api-client/src/ws_client.ts

@@ -13,15 +13,65 @@
  *
  */
 
-import { APIClient } from './api_client';
-import { Channel } from './types';
-
-export const createWSClient = async (url: string): Promise<APIClient> => {
-	// FIXME: requires real implementation
-	const channel = ({ url } as unknown) as Channel;
-	await channel.connect();
-	const client = new APIClient(channel);
-	await client.init();
-
-	return client;
-};
+import * as WebSocket from 'isomorphic-ws';
+
+const CONNECTION_TIMEOUT = 2000;
+const ACKNOWLEDGMENT_TIMEOUT = 2000;
+
+const timeout = async (ms: number, message?: string): Promise<void> =>
+	new Promise((_, reject) => {
+		const id = setTimeout(() => {
+			clearTimeout(id);
+			reject(message ?? `Timed out in ${ms}ms.`);
+		}, ms);
+	});
+
+export class WSClient {
+	public isAlive = false;
+	private readonly _url: string;
+	private _ws?: WebSocket;
+
+	public constructor(url: string) {
+		this._url = url;
+	}
+
+	public async connect(): Promise<void> {
+		this._ws = new WebSocket(this._url);
+
+		const connect = new Promise<void>(resolve => {
+			this._ws?.on('open', () => {
+				this.isAlive = true;
+				resolve();
+			});
+		});
+
+		this._ws.on('ping', () => {
+			this.isAlive = true;
+		});
+
+		return Promise.race([
+			connect,
+			timeout(CONNECTION_TIMEOUT, `Could not connect in ${CONNECTION_TIMEOUT}ms`),
+		]);
+	}
+
+	public async disconnect(): Promise<void> {
+		if (!this._ws) {
+			return Promise.resolve();
+		}
+
+		return new Promise<void>(resolve => {
+			this._ws?.on('close', () => {
+				this.isAlive = false;
+				this._ws = undefined;
+				resolve();
+			});
+			this._ws?.close();
+		});
+	}
+
+	// public async invoke<T>(actionName: string, params?: Record<string, unknown>): Promise<T> {
+	// }
+
+	// public subscribe(eventName: string, cb: EventCallback): void {}
+}

yarn.lock

@@ -6807,6 +6807,11 @@ isobject@^3.0.0, isobject@^3.0.1:
   resolved "https://registry.yarnpkg.com/isobject/-/isobject-3.0.1.tgz#4e431e92b11a9731636aa1f9c8d1ccbcfdab78df"
   integrity sha1-TkMekrEalzFjaqH5yNHMvP2reN8=
 
+isomorphic-ws@4.0.1:
+  version "4.0.1"
+  resolved "https://registry.yarnpkg.com/isomorphic-ws/-/isomorphic-ws-4.0.1.tgz#55fd4cd6c5e6491e76dc125938dd863f5cd4f2dc"
+  integrity sha512-BhBvN2MBpWTaSHdWRb/bwdZJ1WaehQ2L1KngkCkfLUGF0mAWAT1sQUQacEmQ0jXkFw/czDXPNQSL5u2/Krsz1w==
+
 isstream@~0.1.2:
   version "0.1.2"
   resolved "https://registry.yarnpkg.com/isstream/-/isstream-0.1.2.tgz#47e63f7af55afa6f92e1500e690eb8b8529c099a"
@@ -12258,6 +12263,11 @@ ws@7.3.1:
   resolved "https://registry.yarnpkg.com/ws/-/ws-7.3.1.tgz#d0547bf67f7ce4f12a72dfe31262c68d7dc551c8"
   integrity sha512-D3RuNkynyHmEJIpD2qrgVkc9DQ23OrN/moAwZX4L8DfvszsJxpjQuUq3LMx6HoYji9fbIOBY18XWBsAux1ZZUA==
 
+ws@7.4.0:
+  version "7.4.0"
+  resolved "https://registry.yarnpkg.com/ws/-/ws-7.4.0.tgz#a5dd76a24197940d4a8bb9e0e152bb4503764da7"
+  integrity sha512-kyFwXuV/5ymf+IXhS6f0+eAFvydbaBW3zjpT6hUdAh/hbVjTIB5EHBGi0bPoCLSK2wcuz3BrEkB9LrYv1Nm4NQ==
+
 ws@^7.2.3:
   version "7.3.0"
   resolved "https://registry.yarnpkg.com/ws/-/ws-7.3.0.tgz#4b2f7f219b3d3737bc1a2fbf145d825b94d38ffd"