Add foreground service, some cleanup, and start websocket server

src/http/lifecycle/Request.ts

@@ -107,7 +107,7 @@ export class Request extends ScopedContainer implements DataContainer {
         protected clientRequest: IncomingMessage,
 
         /** The native Node.js response. */
-        protected serverResponse: ServerResponse,
+        protected serverResponse?: ServerResponse,
     ) {
         super(Container.getContainer())
         this.registerSingletonInstance(Request, this)

src/http/lifecycle/Response.ts

@@ -66,7 +66,7 @@ export class Response {
         public readonly request: Request,
 
         /** The native Node.js ServerResponse. */
-        protected readonly serverResponse: ServerResponse,
+        protected readonly serverResponse?: ServerResponse,
     ) { }
 
     protected get logging(): Logging {
@@ -173,6 +173,11 @@ export class Response {
      */
     public sendHeaders(): this {
         this.logging.verbose(`Sending headers...`)
+        if ( !this.serverResponse ) {
+            throw new ErrorWithContext('Unable to send headers: Response has no underlying connection.', {
+                suggestion: 'This usually means the Request was created by an alternative server, like WebsocketServer. You should use that server to handle the request.',
+            })
+        }
         const headers = {} as any
 
         const setCookieHeaders = this.cookies.getSetCookieHeaders()
@@ -220,8 +225,14 @@ export class Response {
      * @param data
      */
     public async write(data: string | Buffer | Uint8Array | Readable): Promise<void> {
-        this.logging.verbose(`Writing headers & data to response... (destroyed? ${this.serverResponse.destroyed})`)
+        this.logging.verbose(`Writing headers & data to response... (destroyed? ${!this.serverResponse || this.serverResponse.destroyed})`)
         return new Promise<void>((res, rej) => {
+            if ( !this.serverResponse ) {
+                throw new ErrorWithContext('Unable to write response: Response has no underlying connection.', {
+                    suggestion: 'This usually means the Request was created by an alternative server, like WebsocketServer. You should use that server to handle the request.',
+                })
+            }
+
             if ( this.responseEnded || this.serverResponse.destroyed ) {
                 throw new ErrorWithContext('Tried to write to Response after lifecycle ended.')
             }
@@ -274,7 +285,7 @@ export class Response {
      * or the connection has been destroyed.
      */
     public canSend(): boolean {
-        return !(this.responseEnded || this.serverResponse.destroyed)
+        return !(this.responseEnded || !this.serverResponse || this.serverResponse.destroyed)
     }
 
     /**
@@ -286,7 +297,7 @@ export class Response {
         }
 
         this.sentHeaders = true
-        this.serverResponse.end()
+        this.serverResponse?.end()
         return this
     }