From ad6b0b181ab7259c34b3c3d0c89155a8f036e488 Mon Sep 17 00:00:00 2001
From: Darien Pardinas Diaz <dpar39@gmail.com>
Date: Wed, 28 Aug 2024 21:57:41 -0400
Subject: [PATCH] 0.0.12 - Bug Fix: When executing command "Developer: Reload
 Window", the previous TCP port could not be reused because the old extension
 process was not kill. Now it saves the PID and kills it the next time the
 extension is activated.

---
 CHANGELOG.md     |  4 ++++
 package.json     |  2 +-
 src/extension.ts | 52 ++++++++++++++++++++++++++++++++++++++++++------
 3 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b5530fe..e6bc12b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Change Log
 
+## [0.0.12]
+
+- Bug Fix: When executing command "Developer: Reload Window", the previous TCP port could not be reused because the old extension process was not kill. Now it saves the PID and kills it the next time the extension is activated.
+
 ## [0.0.11]
 
 - Bug Fix for `Access-Control-Allow-Origin: *` response header to allow calling VSCode REST Control from web browsers.
diff --git a/package.json b/package.json
index 80ef86f..5976c39 100644
--- a/package.json
+++ b/package.json
@@ -4,7 +4,7 @@
   "description": "This extension allows you to remotely control Visual Studio Code via a REST endpoint, taking automation to the next level.",
   "publisher": "dpar39",
   "license": "MIT",
-  "version": "0.0.11",
+  "version": "0.0.12",
   "engines": {
     "vscode": "^1.55.0"
   },
diff --git a/src/extension.ts b/src/extension.ts
index b4e488f..23c44ce 100644
--- a/src/extension.ts
+++ b/src/extension.ts
@@ -1,12 +1,12 @@
 import * as vscode from "vscode";
 import * as tcpPorts from "tcp-port-used";
+import * as fs from "fs";
 import { Logger } from "./services/logger";
-import { IncomingMessage, ServerResponse } from "http";
-import * as http from "http";
+import { IncomingMessage, ServerResponse, Server, createServer } from "http";
 import { AddressInfo } from "net";
 import { processRemoteControlRequest } from "./services/requestProcessor";
 
-let server: http.Server;
+let server: Server;
 let statusbar: vscode.StatusBarItem;
 
 export const EXTENSION_ID: string = "dpar39.vscode-rest-control";
@@ -108,7 +108,7 @@ const startHttpServer = async (
     });
   };
   // Start the HTTP server
-  server = http.createServer(requestHandler);
+  server = createServer(requestHandler);
 
   server.listen(isInUse ? 0 : port, host, () => {
     const address = server.address();
@@ -116,6 +116,7 @@ const startHttpServer = async (
     const listeningMessage = `REST Control: Listening on "http://${host}:${verifiedPort}"`;
 
     Logger.info(listeningMessage);
+    saveTcpPortProcessPid(context, verifiedPort);
     // set the remote control port as an environment variable
     setRemoteControlEnvironmentVariable(context, verifiedPort);
     statusbar.text = `$(plug) RC Port: ${verifiedPort}`;
@@ -138,16 +139,55 @@ function getDefaultPortForWorkspace(): number {
   return port;
 }
 
+function httpPortToPid(context: vscode.ExtensionContext, port: number): string {
+  const cacheDir = context.globalStorageUri.fsPath;
+  if (!fs.existsSync(cacheDir)) {
+    fs.mkdirSync(cacheDir, { recursive: true });
+  }
+  return cacheDir + "/" + port + ".pid";
+}
+
+function killPreviousProcessIfUsingTcpPort(
+  context: vscode.ExtensionContext,
+  port: number | undefined
+) {
+  Logger.info(`Checking if we need to kill previous process using port = ${port}`);
+  if (!port) {
+    return;
+  }
+  const portFile = httpPortToPid(context, port!);
+  if (fs.existsSync(portFile)) {
+    try {
+      const pid = fs.readFileSync(portFile, "utf-8");
+      Logger.info(`Found previous PID=${pid} for HTTP port ${port}`);
+      process.kill(parseInt(pid));
+    } catch (e) {
+      Logger.warning(`Unable to kill process specified in ${portFile}`);
+    }
+    fs.unlinkSync(portFile);
+  }
+}
+function saveTcpPortProcessPid(context: vscode.ExtensionContext, port: number | undefined) {
+  if (!port) {
+    Logger.warning(`HTTP port is ${port} - a port should have been selected.`);
+  }
+  const pid = process.pid;
+  Logger.info(`Saving PID=${pid} as currently using HTTP port ${port}`);
+  const portFile = httpPortToPid(context, port!);
+  fs.writeFileSync(portFile, pid.toString());
+}
+
 function setupRestControl(context: vscode.ExtensionContext) {
   const config = vscode.workspace.getConfiguration(SETTINGS_NAME);
   const enabled = config.get<number | null>("enable");
   if (enabled) {
-    const port = config.get<number | null>("port");
+    const port = config.get<number | null>("port") || getDefaultPortForWorkspace();
+    killPreviousProcessIfUsingTcpPort(context, port);
     const fallbackPorts = config.get<number[] | null>("fallbacks");
     startHttpServer(
       context,
       "127.0.0.1",
-      port || getDefaultPortForWorkspace(),
+      port,
       (fallbackPorts || []).filter((p: number) => p !== port)
     );
     Logger.info("VSCode REST Control is now active!");