Windows Executable Shims

This project allows the creation of Windows "executable shims" - exe files that when run, execute a defined command, passing the command line arguments on to the subcommand.

They are similar to the shims used by the Python launcher for Windows, the "pyzzer" Python wrapper project, and the "chocolatey" project.

Usage

Create a shim as follows:

mkshim.py -f filename.exe -c "a command"

This will generate an executable, filename.exe, which when run, will execute a command. So, for example:

filename a b c

runs

a command a b c

Note that there is no requirement for the command to be just an executable name. A common usage might be to run py C:\Some\Python\Script.py.

It is possible to have the supplied arguments inserted somewhere other than at the end of the line, by including %s in the command string. The arguments will be inserted in place of the %s.

Technical Details

The command is executed using the Windows CreateProcess API, so file associations will not be considered when running the subcommand.

The stub executable is built from the stub.c source. The compile command is simply cl /Festub.exe stub.c. The script is built from template.py and the stub exe using build.py.

If you want to use a different stub when building a shim (for example, when testing a change to the stub code) you can use the --stub argument to specify the name of the sub exe directly.

Current WIP changes (undocumented)

The stub now works by taking an appended UTF8 text file. There's a sample in the file "footer". There's a wait element to determine whether to wait for the subcommand, but it defaults to true for a console shim and false for a gui one, so it should never need setting manually.

The command element supports %% (%) %a (the arg list) and %d (the directory of the shim) substitutions.

The "subsystem.py" script is the beginnings of a subsystem editing utility. Comments in the source include the relevant bits of the Windows headers.

With the new system, I'm less sure how useful mkshim/template is. You can create a shim just by writing the footer and doing copy /b stub.exe+footer shim.exe.

Future Possibilities

1. Enhance the command template syntax, for example a %-directive to mean the directory of the stub (to allow running programs relative to the stub).
2. Additional control over the subprocess - altered environment, run in a specific directory, ...?