Python Console Mod

Python Console mod allows you to programatically interact with Cities:Skylines game engine through an easy-to-learn python interface. User documentation can be found on wiki. See the mod in Steam Workshop.

Developer isntructions

After first build:

• Open build folder PythonConsole\SkylinesRemotePythonDotnet\bin\Debug
• Open mod target folder C:\Users\<Username>\AppData\Local\Colossal Order\Cities_Skylines\Addons\Mods\PythonConsole
• Create a zip file SkylinesRemotePython.zip containing the contents of the build folder and move it to the mod target folder
  • For next builds you might copy only the SkylinesRemotePythonDotnet.exe to the zip file (if it has changed)
• Download PyPy 2.7, navigate to lib-python\2.7, copy the content to a new folder pypy and put it to SkylinesRemotePython.zip
• Open example scripts folder PythonConsole\PythonConsole\Resource\Examples
• Create a zip file ExamplePythonScripts.zip containing the contents of the folder and move it to the mod target folder
  • You need to repeat this only if you change any of the example script files
• The mod target folder should now contain these 4 files: ExamplePythonScripts.zip, PythonConsole.dll, SkylinesPythonShared.dll, SkylinesRemotePython.zip
• You can skip some of these steps by copying the files directly from Steam Worksop release of the mod

How does this mod work?

The mod consists of 3 different parts:

• The Cities:Skylines mod itself (PythonConsole.dll)
• External application that runs the IronPython engine
  • Unfortunately the engine cannot run directly inside the game, as it requires dotnet framework 4.0 or higher (C:S runs on mono version 3.5)
• Shared library that contains messaging protocol and shared logic

How does it all work together?

• The external application is shipped in a zip file with the mod
• After the mod loads, the application is unzipped in Cities_Skylines\SkylinesRemotePython folder and launched
• The application creates a tcp server to which the mod then connects

How to develop the mod locally?

• You can run and debug the extarnal Python application directly from Visual Studio
• Go to mod settings in game and enable Debug: Do not launch remote python console server option
  • This will prevent the mod from launching its own instance of Python server
• Now you can start the server in VS and the game will automatically connect to it after you open the Python Console dialog window
• If you want to debug the PythonConsole.dll itself (within Cities:Skylines application domain), you need to attach a dnSpy debugger to the game

How to expose a new API to the Python engine?

• Define a new contract in SkylinesPythonShared/Protocol/Contracts.cs
• Implement the API in PythonConsole/PythonAPI/GameAPI.cs
  • Create a new static fuction with the same name as the contract
  • The contract will be automatically linked to its implementation
• Expose the API in SkylinesRemotePythonDotnet/PythonAPI/GameAPI.cs or wherever else you need

Credits

This mod contains source code from Move It and ModTools