PyRx-based Sample Project

A sample project based on PyRx. This project is created for PyRx users, but most of its elements can be used to create a project not based on PyRx. You might feel that I describe overly simple things in many places, but I want this project to help someone completely new get started. Note: Do not treat this project and its elements as "best practices"; I don't even know if they are good practices, but they are the best ones I know :)

Project Structure

The basic structure of a Python project looks as follows (commit):

.
├── .git
├── src/
│   └── pyrx_sample_project/
│       └── __init__.py
├── tests/
│   └── __init__.py
├── .gitignore
├── pyproject.toml
└── README.md

Virtual Environment

It is recommended to create each project in a separate virtual environment. In the project directory, execute:

$ python -m venv venv
$ venv\Scripts\activate.bat
(venv) $ python -V
Python 3.12.7  # ensure the virtual environment has the correct Python version

This will create and activate a virtual environment - the console prompt will display (venv) before the path.

To install the required dependencies (in our case cad-pyrx), execute the following command within the virtual environment:

python -m pip install -e .[dev]

This command will install our package in editable mode. You need to run this command every time new dependencies are added to the project.

Sample Module

(commit)

For demonstration purposes, we will create a module rect.py with the function create_rectangle and a module cmds.py adding the command PYRECT:

rect.py
cmds.py

Additionally, we will create tests:

test_rect.py

We also need to add a module to run the tests:

testrunner.py

This module will add the RUN_TESTS command after being loaded into CAD.

To ensure the testrunner.py module loads automatically into the CAD application, we need to add a file pyrx_onload.py in the project directory:

pyrx_onload.py

Running the CAD Application

For development purposes, the best way to run the host application seems to be using the command line. In the virtual environment, execute:

zwcad /ld venv\Lib\site-packages\pyrx\RxLoaderZ25.0.zrx

• Specify the name of the host application if its exe file is in the search path or provide the full path to the CAD application's exe file,
• Provide the path to the RxLoader file appropriate for your CAD application,
• In AutoCAD, you may also need to specify the /six parameter in the command line.

Distribution

(commit)

In this tutorial, we treat our package as the "final product." However, if we wanted to distribute our package as a library installable via pip, we would need to build a whl distribution. To do this, execute:

(venv) > python -m build

The .whl (and .tar.gz) files will be placed in the dist directory.

As mentioned earlier, we treat our package as the final product, so we will want to create an installer. I use an SFX archive for this purpose. It is not the simplest approach but probably the most flexible.

The process is as follows:

• Build an exe file based on the SFX archive using the build_setup.py module. This module:
  • Builds the whl distribution of our package,
  • Creates an archive containing the files:
    • setup.bat,
    • bootstrap.py,
    • loader.lsp,
    • loader.py,
• When the exe file is run on the user's computer, the archive will unpack into a temporary directory and execute the setup.bat file,
• The setup.bat file:
  • Installs Python (if it doesn't exist) in a global location (%localappdata%\Programs\Python\Python312),
  • Executes the bootstrap.py file located in the archive,
• The bootstrap.py file:
  • Creates an installation directory,
  • Installs our package from the .whl file along with dependencies,
  • Copies the loader.py file,
  • Creates the loader.lsp file,
• The loader.lsp file should be added to the list of scripts executed at the start of the CAD application. This script:
  • Loads the appropriate version of the PyRx module,
  • Loads the loader.py file,
• The loader.py file:
  • Adds our installation directory to Python's search path (sys.path),
  • Loads the commands (cmds.py module).