bonnet

bonnet is a Windows program that allows you to open a webpage into a self-hosted window and, optionally, to launch a backend process.

Installation

bonnet is just an executable that depends on:

• Visual C++ runtime
• WebView2 runtime

Be sure you have both installed on your system to use bonnet.

Usage details

By default, bonnet displays the help on a 1024x768 window.

Available options:

Launch your front-end and back-end with a single command
Usage:
  bonnet [OPTION...]

      --help                 Display this help
      --width arg            Window width (default: 700)
      --height arg           Window height (default: 600)
      --title arg            Window title (default: bonnet)
      --icon arg             Window icon path (default: "")
      --kiosk-mode           Fullscreen borderless mode
      --maximize             Maximize window
      --url arg              Navigation url (default: "")
      --backend arg          Backend process (default: "")
      --backend-workdir arg  Backend process working dir (default: "")
      --backend-args arg     Backend process arguments (default: "")
      --backend-console      Show console of backend process
      --backend-no-log       Disable backend output to file
      --debug                Enable build tools
      --no-log               Disable all logs to file

By default, bonnet creates a log file bonnet.txt on the current directory. To disable logging, you can add --no-log.

Some examples:

Customize window

bonnet --width 500 --height 500 --title "Italian C++ Community" --icon c:\icons\myicon.ico

Webpage kiosk-mode

To lock down user experience on fullscreen and bordeless window, use --kiosk-mode:

bonnet --kiosk-mode --url https://italiancpp.org

Enable developer tools

Use --debug to enable developer tools:

bonnet --fullscreen --url https://italiancpp.org --debug

Custom backend process

bonnet can optionally launch and hold a process in background. This feature is useful when you need to pair the front-end window with a backend process.

Here is an example:

bonnet --fullscreen --url https://your-frontend --backend your-exe.exe

Backend arguments might be added with --backend-args=arg1,arg2,...:

bonnet --fullscreen --url https://italiancpp.org --backend your-exe.exe --backend-args=arg1,arg2

By default, bonnet redirects backend's standard output into the log file bonnet.txt. To disable such a redirection, launch the program with backend-no-log.

Sometimes, you might want to show the backend process into its own console (and in this case, standard output won't be logged to file). Then, use --backend-console:

bonnet --fullscreen --url https://italiancpp.org --backend your-exe.exe --backend-args=arg1,arg2 --backend-console

You can even customize the backend process working directory with backend-workdir path.

Last but not least, when bonnet's window is closed, the backend process will receive a CTRL+C. Thus, for correctly handling this graceful shutdown, it's mandatory that your backend process is a console application and that you don't launch bonnet with START /B.

Backend process management

As briefly described above, bonnet can optionally launch a process in background. We call this process backend.

The backend process is simply launched and then managed as follows:

• if the window (the frontend) is closed then bonnet sends a graceful shutdown (CTRL+C) to the backend (if the backend doesn't exit within 2 seconds, it gets killed);
• on the other hand, if the backend process exits (either successfully or not) then bonnet closes the window and exits the program as well.

A typical use case is when you have a kiosk-mode application that does not allow the user to close the window by hand but, instead, you let the backend receive a command and shutdown.

Development

The idea of bonnet comes from gimmi. I am merely the programmer who has implemented it in C++20 with the support of:

• cxxopts
• webview
• tiny-process
• WebView2 nuget package

For simplicity, the latter only is installed as a Nuget package into the project, the others are stored in deps/. A few changes have been made to webview and tiny-process to accommodate our needs (search the code for ilpropheta: for details).

The name bonnet is an idea of mine who sometimes wants to name things after famous pirates. As Stede Bonnet tried with might and main turning to piracy despite his lack of sailing experience, here I am developing a WebView2 program without any previous experience with that technology!