With the introduction of the 4D Debugger extension for Visual Studio Code, developers can now debug 4D applications more efficiently. A key part of this setup is the launch.json file, which allows you to customize how VS Code interacts with your 4D Server. Here’s how to configure it for optimal debugging.

Understanding launch.json in 4D Debugger

The launch.json file is used to configure how the debugger attaches to or launches a 4D Server. Depending on your workflow, you can use one of the following approaches:

• Attach: Connect to a running 4D Server instance.


• Attach and Run: Attach to an active 4D Server and execute a specific 4D method.
  


• Launch: Start a new 4D Server instance before debugging.


• Launch and Run: Launch a 4D Server, attach the debugger, and run a predefined method.

Essential launch.json configuration

Below is a sample configuration that includes both launching a new server and attaching to an existing one:

{
 "version": "0.2.0",
 "configurations": [
 {
   "type":"4d",
   "request":"launch",
   "name":"Launch 4D Server",
   "project":"${workspaceFolder}/Project/${workspaceFolderBasename}.4DProject",
   "program": "${workspaceFolder}/Sources/MainMethod.4dm",
   "execArgs": ["--debug"],
   "exec": "C:/Program Files/4D/4D Server/4DServer.exe",
   "port": 19815 // server port + 2
 },
 {
   "type": "4d",
   "request": "attach",
   "name": "Attach to Running 4D Server",
   "port": 19815, // server port + 2
   "program": "${file}"
  }
  ]
}

Best Practices for launch.json

• Use the Right request Type: If your 4D Server is already running, use "attach" instead of "launch" to prevent conflicts.


• Define the program Property: For "Attach and Run" or "Launch and Run" modes, specify the 4D method to execute immediately upon debugging.


• Customize execArgs: Add debugging options like "--debug" for more verbose output.


• Set the exec Path When Needed: If you’re working with multiple 4D Server versions, define the absolute path in the exec property.


• Check the Port Configuration: The default port is 19815, but it’s determined dynamically based on your 4D Server configuration (Application Server port + 2).

Final insights

By fine-tuning your `launch.json`, you can streamline your debugging workflow and eliminate unnecessary setup time. Whether you’re launching a new instance or attaching to an active one, properly configuring this file ensures smooth debugging in VS Code.

For more details, refer to the official : 4D Debugger documentation