Feature Pack System
How packs are discovered, loaded, ordered, and invoked.
Feature Packs are the capability decomposition mechanism in Ghost Downloader. app/services/feature_service.py scans the features directory for subdirectories containing manifest.toml, reads the entry file and dependencies, and then instantiates the matching pack class.
API Stability
This page documents internal implementation details, not a stable external plugin API. app/feature_pack and features/*_pack may still change together with the task model.
Loading Flow
| Step | Description |
|---|---|
| Discovery | Find features/<pack>/manifest.toml. |
| Manifest read | Load entry and dependencies from [pack]. |
| Dependency ordering | Load packs in dependency order, for example media features may depend on FFmpeg. |
| Instantiation | Import the Feature Pack class from the entry module. |
| UI registration | Load settings cards if the pack provides any. |
| URL matching | Ask packs whether they can handle the current input during parsing. |
Implementation Checklist
| Checklist Item | Where It Lands |
|---|---|
| Input coverage | canHandle or payload-based task creation logic. |
| Pack dependencies | dependencies in manifest.toml. |
| Task type | Task subclass, pause/resume behavior, persistence fields. |
| User config | PackConfig, settings cards, defaults, and validators. |
| Error messages | Readable failure messages for parse failures, missing dependencies, or network errors. |
Minimal Manifest Example
[pack]
entry = "pack.py"
dependencies = ["http_pack"]A pack directory usually contains at least manifest.toml and an entry file. More complex packs may also include task.py, config.py, runtime helpers, or UI setting cards. In a PR, explain supported inputs, dependencies, pause support, and failure scenarios.
Related Entry Points
| Entry Point | Purpose |
|---|---|
app/services/feature_service.py | Discover and load packs. |
app/feature_pack | Current shared Feature Pack base capabilities. |
features/http_pack | The easiest simple protocol pack to start reading. |
features/m3u8_pack | A more complex pack that depends on external runtimes. |
deploy.py | Copies Feature Packs into build outputs and currently excludes jack_yao. |