Wabbajack - An automated modlist installer for TES/Fallout games

The general idea behind this program is fairly simple. Given a Mod Organizer 2 folder and profile, generate list of instructions that will allow a program to automatically recreate the contents of the folder on another machine. Think of it as replication, but without ever distributing copyrighted files or syncing data between the source and destination machine. The end result is a program that recreate a modlist on a computer while respecting the rights of the game publisher and the mod authors.

Social Links

• Discord
• [Patreon] (https://www.patreon.com/user?u=11907933) Check this page for updates and to vote on features

How it works

At a technical level the process is as follows.

1. Hash and cache the contents of every archive in the \downloads folder. This lets Wabbajack know of all the possible locations where you could have installed mods
2. Apply the resolution stack to every file in both the game's root folder and in the MO2 folder.
3. Take the install directives and required archives and write their metadata to a JSON file.
4. Attach the JSON file to Wabbajack itself, creating a new Auto-installer for the profile

The Resolution Stack

Every file analyzed by Wabbajack is passed through a stack of rules. The first rule to match the file creates a Install Directive or a instruction on how to install that specific file.

Currently the Resolution stack looks like this:

1. Ignore the contents of logs\
2. Ignore the contents of downloads\
3. Ignore the contents of webcache\
4. Ignore the contents of overwrite\
5. Ignore .pyc files
6. Ignore any files in profiles that are not for the selected MO2 profile
7. Ignore any disabled mods
8. Include any profile settings for the selected profile by including them directly in the modlist
9. Ignore "ModOrganizer.ini", it will be re-created when MO2 starts on the new machine
10. Ignore "Data" in the Game directly (in your Steam folder)
11. Ignore "Papyrus Compiler" in the game folder
12. Ignore the "Skyrim" folder in the game folder
13. Ignore any BSAs in the game folder
14. Include all meta.ini files from all (selected) mods
15. Include archive and file meta information for any file that matches a file in an archive directly via a SHA256 comparison
16. Generate patches for files that may have been modified after being installed from an archive (see section on Patching for more info)
17. Deconstruct BSAs to see if they can be created by generating a BSA from assembing files and patches from archives
18. Ignore files in the game directory
19. Ignore .ini files
20. Ignore .html files (normally these are logs)
21. Ignore .txt files
22. Ignore HavockBehaviourPostProcess.exe this seems to get copied around by tools for some reason
23. Error for any file that survives to this point.

So as you can see we handle a lot of possible install situations. See the section on Creating a Modpack for information on working with the installer

Patches

Wabbajack can create binary patches for files that have been modified after installation. This could be .esp files that have been cleaned or patched. Or it could be meshes and textures that have been optimized to work better in a given game. In any case a BSDiff file is generated. The output of this process is copied directly into the modlist instructions. However! It is important to note that the patch file is 100% useless without the source file. So original + patch = final_file without the original file, the final file cannot be recrated. This allows us to distribute arbitrary changes without violating copyrights as we do not copy copyrighted material. Instead we copy instructions on how to modify the copyrighted material.

Archive Sources

Wabbajack can currently install from many different file hosting sources. Currently these consist of:

• Nexus Mods - Only Premium accounts, this restriction will not change. They host a lot of files and support the community, respect the service they provide.
• HTTP Servers - Bare HTTP downloads are supported, additional headers can also be passed to the server
• Dropbox
• Google Drive
• MEGA
• ModDB

FAQ

Why does each modpack install another copy of Mod Organizer 2

Self-contained folders are a cleaner abstraction than dumping tons of modlists into the same set of folders. It's easy to uninstall a modlist (simply delete the folder), and MO2 really isn't designed to support lots of disparate modlists. For example if two modlists both wanted a given texture mod, but different options they would somehow have to keep the names of their mods separate. MO2 isn't that big of an app, so there's really no reason not to install a new copy for each modlist.

License & Copyright

All original code in Wabbajack is given freely via the GPL3 license. Parts of Wabbajack use libraries that carry their own Open Sources licenses, those parts retain their original copyrights. Note: Wabbajack installers contain code from Wabbajack. Therefore, selling of modlist files is strictly forbidden. As is hosting the files behind any sort of paywall. You recieved this tool free of charge, respect this by giving freely as you were given.