feat: Split up server creation and request handling

This allows us to decouple the WebSocket listening from the HTTP configs,
making these features completely orthogonal.

src/http/UnsecureWebSocketsProtocol.ts

@@ -1,21 +1,27 @@
-import { EventEmitter } from 'events';
+import type { IncomingMessage } from 'http';
 import type { TLSSocket } from 'tls';
 import type { WebSocket } from 'ws';
 import type { SingleThreaded } from '../init/cluster/SingleThreaded';
 import { getLoggerFor } from '../logging/LogUtil';
-import type { HttpRequest } from '../server/HttpRequest';
-import { WebSocketHandler } from '../server/WebSocketHandler';
+import type { ActivityEmitter } from '../server/notifications/ActivityEmitter';
+import { WebSocketServerConfigurator } from '../server/WebSocketServerConfigurator';
+import { createErrorMessage } from '../util/errors/ErrorUtil';
+import type { GenericEventEmitter } from '../util/GenericEventEmitter';
+import { createGenericEventEmitterClass } from '../util/GenericEventEmitter';
 import { parseForwarded } from '../util/HeaderUtil';
 import { splitCommaSeparated } from '../util/StringUtil';
 import type { ResourceIdentifier } from './representation/ResourceIdentifier';
 
 const VERSION = 'solid-0.1';
 
+// eslint-disable-next-line @typescript-eslint/naming-convention
+const WebSocketListenerEmitter = createGenericEventEmitterClass<GenericEventEmitter<'closed', () => void>>();
+
 /**
  * Implementation of Solid WebSockets API Spec solid-0.1
  * at https://github.com/solid/solid-spec/blob/master/api-websockets.md
  */
-class WebSocketListener extends EventEmitter {
+class WebSocketListener extends WebSocketListenerEmitter {
   private host = '';
   private protocol = '';
   private readonly socket: WebSocket;
@@ -30,7 +36,7 @@ class WebSocketListener extends EventEmitter {
     socket.addListener('message', (message: string): void => this.onMessage(message));
   }
 
-  public start({ headers, socket }: HttpRequest): void {
+  public start({ headers, socket }: IncomingMessage): void {
     // Greet the client
     this.sendMessage('protocol', VERSION);
 
@@ -105,7 +111,7 @@ class WebSocketListener extends EventEmitter {
       this.logger.debug(`WebSocket subscribed to changes on ${url}`);
     } catch (error: unknown) {
       // Report errors to the socket
-      const errorText: string = (error as any).message;
+      const errorText: string = createErrorMessage(error);
       this.sendMessage('error', errorText);
       this.logger.warn(`WebSocket could not subscribe to ${path}: ${errorText}`);
     }
@@ -120,11 +126,11 @@ class WebSocketListener extends EventEmitter {
  * Provides live update functionality following
  * the Solid WebSockets API Spec solid-0.1
  */
-export class UnsecureWebSocketsProtocol extends WebSocketHandler implements SingleThreaded {
-  private readonly logger = getLoggerFor(this);
+export class UnsecureWebSocketsProtocol extends WebSocketServerConfigurator implements SingleThreaded {
+  protected readonly logger = getLoggerFor(this);
   private readonly listeners = new Set<WebSocketListener>();
 
-  public constructor(source: EventEmitter) {
+  public constructor(source: ActivityEmitter) {
     super();
 
     this.logger.warn('The chosen configuration includes Solid WebSockets API 0.1, which is unauthenticated.');
@@ -133,8 +139,8 @@ export class UnsecureWebSocketsProtocol extends WebSocketHandler implements Sing
     source.on('changed', (changed: ResourceIdentifier): void => this.onResourceChanged(changed));
   }
 
-  public async handle(input: { webSocket: WebSocket; upgradeRequest: HttpRequest }): Promise<void> {
-    const listener = new WebSocketListener(input.webSocket);
+  protected async handleConnection(webSocket: WebSocket, upgradeRequest: IncomingMessage): Promise<void> {
+    const listener = new WebSocketListener(webSocket);
     this.listeners.add(listener);
     this.logger.info(`New WebSocket added, ${this.listeners.size} in total`);
 
@@ -142,7 +148,7 @@ export class UnsecureWebSocketsProtocol extends WebSocketHandler implements Sing
       this.listeners.delete(listener);
       this.logger.info(`WebSocket closed, ${this.listeners.size} remaining`);
     });
-    listener.start(input.upgradeRequest);
+    listener.start(upgradeRequest);
   }
 
   private onResourceChanged(changed: ResourceIdentifier): void {