Allow different host executable file extension, not only .exe

[tansautn]

I'm developing small extension with NHM. I used .bat file for NHM entry point.

Here is log from NMD:

18:12:56:7651 - I am [z2dlp_host.proxy.bat.exe:16772], launched by [cmd:20152].
18:12:56:7661 - GetStartupInfo() says dwFlags=0x0, excludes STARTF_USESTDHANDLES; stdin=0xffffffffffffffff; stdout=0xffffffffffffffff; stderr=0xffffffffffffffff.
18:12:56:7671 - GetStdHandle() says stdin=(0x8, FileTypePipe); stdout=(0xc, FileTypePipe); stderr=(0x0, FileTypeUnknownHandleInvalid).
18:12:56:7671 - extension: chrome-extension://pedcomindcpbnadoenfgnjandcieiani/
18:12:56:7671 - parent-window: 001213bc 
18:12:56:7671 - Listening for messages...
18:12:56:7981 - Checking for D:\Z-Data\git\qt-apps\yt-2dlp-ext\native_host\z2dlp_host.bat.exe...
18:12:56:7981 - Did not find any likely nativeHost for pedcomindcpbnadoenfgnjandcieiani. If you are using this tool as a mock,
the Injector tab allows sending messages to the browser.
18:12:56:7981 - GetStdHandle() says stdin=(0x8, FileTypePipe); stdout=(0xc, FileTypePipe); stderr=(0x0, FileTypeUnknownHandleInvalid).
18:12:56:8091 - {"action":"ping"}
18:13:06:2561 - Injecting message to extension '{"example_1": "to browser", "field_2": 2, "field_3":false}'
18:13:13:5834 - Got EOF while trying to read message size from (Extension); got only 0 bytes. Disconnecting.

Here is host manifest (proxied)

{
  "name": "z2dlp_host",
  "description": "z2dlp Native Messaging Host",
  "path": "D:\\Z-Data\\git\\qt-apps\\yt-2dlp-ext\\native_host\\z2dlp_host.proxy.bat.exe",
  "type": "stdio",
  "allowed_origins": [
    "chrome-extension://pedcomindcpbnadoenfgnjandcieiani/",
    "chrome-extension://edcocgnlkdijkkiebalenphmfakmmoif/"
  ],
  "allowed_extensions": ["z2dlp_ext@zuko.pro"]
}

The real path of NHM is D:\\Z-Data\\git\\qt-apps\\yt-2dlp-ext\\native_host\\z2dlp_host.bat

I also tried "path": "D:\\Z-Data\\git\\qt-apps\\yt-2dlp-ext\\native_host\\z2dlp_host.bat.proxy.exe",

but chrome give

[296:15180:0115/182248.856:WARNING:launch_context.cc(195)] Found manifest, but not the binary for native messaging host z2dlp_host. Host path specified in the manifest: D:\Z-Data\git\qt-apps\yt-2dlp-ext\native_host\z2dlp_host.bat.proxy.exe
[296:17800:0115/182248.856:INFO:CONSOLE(554)] "Native host test error: Error: Specified native messaging host not found.", source: chrome-extension://pedcomindcpbnadoenfgnjandcieiani/options/options.js (554)

Then i rename NMD to z2dlp_host.bat.proxy.exe, doing test again. We back to Did not find any likely nativeHost for situation

[ericlaw1979]

Thanks for reporting!

I used .bat file for NHM entry point.

Fascinating. I'm a bit shocked that ever works, and it will not work with this extension, which I wrote with the expectation that it be used with a .exe backed native host. I'd love to see what your batch file looks like to understand how this scenario is implemented.

There are definitely configurations where I wouldn't expect a batch file to work in the real-world (e.g. if the system has CMD disabled) even without the debugger.

[tansautn]

Thank you, I just hope that more people can access this useful debugging tool.

For me, compiling the host into a .exe file isn't too difficult or time-consuming. However, using a .bat launcher is a much more time- and effort-saving approach for me. That's why I chose to use it.
And if I remember correctly, on MDN (Mozilla), their guide on NHM also uses a .bat file as the entry point.

Below is my .bat script. It's simply a Python launcher—nothing mysterious here.

@echo off
setlocal DisableDelayedExpansion
set "SCRIPT_PATH=%~f0"
set "START_DIR=%~dp0"
for %%I in ("%SCRIPT_PATH%") do set "PROJECT_DIR=%%~dpI..\"

:: Check if .git exists in the parent directory
if not exist "%PROJECT_DIR%.git" (
    echo This file is only for development purposes.
    echo It should not be used in production.
    pause
    exit /b 1
)

:: Check if the virtual environment exists
if not exist "%PROJECT_DIR%venv\Scripts\activate.bat" (
    echo Virtual environment not found. Make sure it's named "venv".
    pause
    exit /b 1
)

:: Activate the virtual environment
call "%PROJECT_DIR%venv\Scripts\activate.bat"
timeout /t 2 /nobreak > nul

:: Run the Python script
python "z2dlp_host.py" %*
exit /b