From d9b23c17dbaefa3b4b0fd3faee5f81c289a9629d Mon Sep 17 00:00:00 2001
From: myst <chr.kellner@live.de>
Date: Mon, 4 Nov 2024 18:42:29 +0100
Subject: [PATCH] feat(backend): enabled status requests on demand

---
 .../models/telnet-status-subnogiation.ts      |  3 ++
 backend/src/features/telnet/telnet-client.ts  | 39 +++++++++++++++++++
 .../telnet/utils/handle-status-option.ts      |  8 ----
 3 files changed, 42 insertions(+), 8 deletions(-)
 create mode 100644 backend/src/features/telnet/models/telnet-status-subnogiation.ts

diff --git a/backend/src/features/telnet/models/telnet-status-subnogiation.ts b/backend/src/features/telnet/models/telnet-status-subnogiation.ts
new file mode 100644
index 0000000..f57e1b9
--- /dev/null
+++ b/backend/src/features/telnet/models/telnet-status-subnogiation.ts
@@ -0,0 +1,3 @@
+export enum TelnetStatusSubnogiation {
+  STATUS_SEND = 1,
+}
diff --git a/backend/src/features/telnet/telnet-client.ts b/backend/src/features/telnet/telnet-client.ts
index f17f242..27aabc2 100644
--- a/backend/src/features/telnet/telnet-client.ts
+++ b/backend/src/features/telnet/telnet-client.ts
@@ -5,6 +5,7 @@ import tls from 'tls';
 
 import { logger } from '../../shared/utils/logger.js';
 import { TelnetOptions } from './models/telnet-options.js';
+import { TelnetStatusSubnogiation } from './models/telnet-status-subnogiation.js';
 import { TelnetControlSequences } from './types/telnet-control-sequences.js';
 import { TelnetNegotiations } from './types/telnet-negotiations.js';
 import { TelnetOptionHandler } from './types/telnet-option-handler.js';
@@ -99,12 +100,50 @@ export class TelnetClient extends EventEmitter<TelnetClientEvents> {
     this.telnetSocket.on('data', (chunkData: string | Buffer) => {
       this.emit('data', chunkData);
     });
+
+    this.on('negotiationChanged', (negotiation) => {
+      // Request initial status data after negotiation - we use TTYPE since this is subnegotiated the last
+      // Todo[myst]: Find a better way to do this but its not that easy, since everything is async
+      if (negotiation.option === TelnetOptions.TELOPT_TTYPE) {
+        this.requestStatus();
+      }
+    });
   }
 
   public sendMessage(data: string): void {
     this.telnetSocket.write(data);
   }
 
+  public requestStatus(): void {
+    const buffer = Buffer.from([TelnetStatusSubnogiation.STATUS_SEND]);
+
+    if (!this.connected) {
+      return;
+    }
+
+    const clientOption =
+      this._negotiations[TelnetOptions.TELOPT_STATUS]?.client;
+
+    const serverOption =
+      this._negotiations[TelnetOptions.TELOPT_STATUS]?.server;
+
+    if (
+      clientOption === undefined ||
+      clientOption !== TelnetControlSequences.DO
+    ) {
+      return;
+    }
+
+    if (
+      serverOption === undefined ||
+      serverOption !== TelnetControlSequences.WILL
+    ) {
+      return;
+    }
+
+    this.telnetSocket.writeSub(TelnetOptions.TELOPT_STATUS, buffer);
+  }
+
   public disconnect(): void {
     logger.info(`[Telnet-Client] Disconnect`);
 
diff --git a/backend/src/features/telnet/utils/handle-status-option.ts b/backend/src/features/telnet/utils/handle-status-option.ts
index 206f752..eb2f0eb 100644
--- a/backend/src/features/telnet/utils/handle-status-option.ts
+++ b/backend/src/features/telnet/utils/handle-status-option.ts
@@ -5,10 +5,6 @@ import { TelnetControlSequences } from '../types/telnet-control-sequences.js';
 import { TelnetOptionHandler } from '../types/telnet-option-handler.js';
 import { TelnetOptionResult } from '../types/telnet-option-result.js';
 
-enum TelnetStatusSubnogiation {
-  STATUS_SEND = 1,
-}
-
 const handleStatusDo = (socket: TelnetSocket) => (): TelnetOptionResult => {
   socket.writeWill(TelnetOptions.TELOPT_STATUS);
 
@@ -24,10 +20,6 @@ const handleStatusDont = (socket: TelnetSocket) => (): TelnetOptionResult => {
 const handleStatusWill = (socket: TelnetSocket) => (): TelnetOptionResult => {
   socket.writeDo(TelnetOptions.TELOPT_STATUS);
 
-  const buffer = Buffer.from([TelnetStatusSubnogiation.STATUS_SEND]);
-
-  socket.writeSub(TelnetOptions.TELOPT_STATUS, buffer);
-
   return { controlSequence: TelnetControlSequences.DO };
 };