bevy-dlc 1.18.6

DLC (downloadable content) management for Bevy games
Documentation

Crates.io docs.rs License: MIT

Encrypt and ship your DLC! Create your DLC logic and assets and securely unlock it at runtime with signed licenses (generated using bevy-dlc CLI).

Works with Bevy's asset pipeline.

Features

  • Pack assets into encrypted .dlcpack containers
  • Sign licenses with Ed25519 (private key embeds the symmetric encryption key)
  • Verify signatures at runtime and unlock encrypted content
  • Lazy loading of labeled assets (e.g. pack.dlcpack#sprites/player.png)
  • Product binding — prevent token reuse across games
  • Security checks to prevent common mistakes like packing executables or other packs

Install

Add to your Cargo.toml:

cargo add bevy-dlc

[!NOTE] bevy-dlc will always be compatible with Bevy 1.## with the minor version being used for bug fixes and new features. So bevy-dlc = "1.18" will also work and automatically get you any compatible bug fixes.

To use the CLI tool:

cargo install bevy-dlc

Then bevy-dlc --help for available commands.

Quick Start

Generate a license

bevy-dlc generate -o keys/ my-game dlcA

This will generate two files in keys/:

  • dlcA.slicense — a secure license token that can be safely embedded in your game binary (e.g. with secure::include_secure_str_aes!()) or stored securely on disk. This token contains the encrypted symmetric key needed to unlock the DLC, but can't be decrypted without the private key.
  • dlcA.pubkey — the public key that your game uses to verify the license and extract the symmetric key to unlock the DLC.

Create a pack

bevy-dlc pack --product my-game dlcA -o dlc -- assets/dlcA
  • --product — binds the pack to a product name
  • assets/dlcA — directory or file(s) to pack
  • dlcA — DLC ID (used in licenses to unlock this pack)
  • -o dlc — output path for the generated .dlcpack
  • --types — optional list of asset type paths to include in the pack index (e.g. bevy::prelude::Image), otherwise all assets will be indexed with their full type paths. This can be used to normalize type paths across different versions of Bevy or your game. The types you specify are fuzzy matched against the actual asset types in the pack, so you can just specify assets::MyAsset and it will match my_game::assets::MyAsset in the pack if that's the actual type.

This creates dlcA.dlcpack and prints a signed license token.

Alternatively you can use bevy-dlc generate --help to review how to generate a signed license without packing, or bevy-dlc validate --help to verify it.

[!NOTE] bevy-dlc help <command> for detailed usage of each CLI command.

Edit a pack

You can edit the contents of a .dlcpack with bevy-dlc edit:

bevy-dlc edit <my_dlc>.dlcpack

This opens an interactive REPL where you can add/remove files, list contents, or even merge entries from another .dlcpack (use merge <other-pack>). Changes are saved back to the .dlcpack when you save and if you forget and exit, REPL will ask you. REPL is not a AI.

Use help within the REPL for available commands.

Usage

Review the examples for a complete example (run with cargo run --release --example <example>).

API Overview

  • DlcLoader is a low‑level loader that decrypts an individual file extracted from a .dlcpack container and then forwards the resulting bytes to whatever concrete loader would normally handle that extension. It’s largely a pass‑through wrapper, and DlcPackLoader uses it under the hood when you load a full .dlcpack with entries (pack.dlcpack#entry.png).
  • DlcPack is a custom Bevy Asset that represents a loaded DLC pack, and contains the decrypted asset data and metadata. You can load it directly with AssetServer::load("my_pack.dlcpack").
  • DlcPackEntry represents a single asset within a pack, and can be loaded with AssetServer::load("my_pack.dlcpack#path/to/asset.png") (note the # separator). You can also query the DlcPack directly for its entries.
  • Events are emitted when packs and entries are loaded, so you can react to them with Bevy's event system.
    • DlcPackLoaded — emitted when a pack is loaded and decrypted, contains the DlcId and DlcPack.
  • Finally, DlcPlugin is the main plugin that sets up the DLC system. It requires a DlcKey::Public and SignedLicense to verify and unlock packs.

Helper macros

The crate exports a few convenient macros to reduce boilerplate when dealing with DLC packs and assets. They are defined in src/macros.rs and available at the crate root:

  • pack_items! – build a Vec<PackItem> from literal path/bytes pairs, with optional ext= or type= metadata.
  • dlc_register_types!(app, ..) – call register_dlc_type for multiple types at once.
  • dlc_simple_asset!(Asset, Loader, Plugin, "ext"...) – define a simple text-like asset type, its loader, and a Bevy plugin that registers both. The examples use this macro to keep the sample assets minimal. (best for testing quickly, not recommended for production use)

This convenience tooling is mostly useful for tests and small examples, but can also speed up rapid prototyping in your own games.

Suggestions and Contributions

Contributions are very welcome! Please open an issue or submit a pull request with any improvements, bug fixes, or new features.

License

MIT