The game Factorio uses a custom binary file format to save certain game data, including the mod-settings.dat file. While these settings may be modified via the in-game UI, this isn't possible when running a dedicated server: the mod-settings.dat file must be pre-loaded with the correct values during world generation.
This repository contains a codec for Factorio game data (implemented in Python) that can convert the mod-settings.dat file to JSON and back, making it possible to adjust the settings without having to create and upload a local world or hex-edit the file.
To decode the settings, run in Command Prompt or PowerShell:
> python factorio_data.py c:\...\mods\mod-settings.dat
Reading DAT file 'c:\...\mods\mod-settings.dat'...
Writing JSON file 'c:\...\mods\mod-settings.json'...
Edit the mod-settings.json file in Notepad or any other text editor.
To re-encode the settings, run in Command Prompt or PowerShell:
> python factorio_data.py c:\...\mods\mod-settings.json
Reading JSON file 'c:\...\mods\mod-settings.json'...
Writing DAT file 'c:\...\mods\mod-settings.dat'...
If no modifications were made, the resulting DAT file must be bit-for-bit identical to the original DAT file. (If it is not, please file an issue on this repository, and attach the problematic DAT file for investigation.)
On Windows, running the python command may cause Windows Store to open and prompt you to install Python. Do so. Otherwise, if you don't have Python installed, download and install it first.
The mod-settings.dat file format is very similar to several other Factorio file formats, including the level-init.dat and script.dat files from saved games. However, these files contain additional data that isn't handled by this codec, and so it cannot decode them to JSON.