classLoader

class Loader(

version: str,

minecraft: str,

)

A specific mod loader version. Subclass it to support another loader.

version

The loader version.

Type:

str

minecraft

The Minecraft version it targets.

Type:

str

kind

The name it is registered under, such as neoforge.

Type:

ClassVar[str]

classmethod available(

minecraft: str,

*,

session: Session | None = None,

) → list[LoaderVersion]

List this loader’s versions for a Minecraft version, newest first.

Override it so versions and recommended can offer the loader.

Parameters:

• minecraft (str) – The Minecraft version.

• session (Session | None) – The session to use. A temporary one is created if omitted.

Returns:

The versions, empty if the loader does not support that Minecraft version. At most one is marked recommended.

Raises:

• UnsupportedError – The loader cannot list its versions. That is the default.

• NetworkError – The loader’s version list could not be fetched.

Return type:

list[LoaderVersion]

classmethod from_version(

version: Version,

minecraft: str,

) → Self | None

Recognise this loader in an installed version JSON.

Override it so detect can find the loader in game directories.

Parameters:

• version (Version) – One version JSON of an installed version, which may inherit from others.

• minecraft (str) – The Minecraft version at the root of its inheritance.

Returns:

The loader, or None if the version JSON is not this loader’s. That is the default.

Return type:

Self | None

abstractmethod version_id(

*,

session: Session | None = None,

cache_dir: Path | None = None,

) → str

Return the id this loader installs under in the versions directory.

Parameters:

• session (Session | None) – The session to use. A temporary one is created if omitted.

• cache_dir (Path | None) – The cache directory. Defaults to the per-user cache.

Returns:

The version id.

Return type:

str

abstractmethod install(

game: GameDir,

*,

java: Path | None = None,

cache_dir: Path | None = None,

session: Session | None = None,

progress: Callable[[Progress], None] | None = None,

cancel: CancelToken | None = None,

) → str

Install into game if needed and return the version id.

Parameters:

• game (GameDir) – The game directory.

• java (Path | None) – The Java binary to use, if the loader needs one.

• cache_dir (Path | None) – The cache directory. Defaults to the per-user cache.

• session (Session | None) – The session to use. A temporary one is created if omitted.

• progress (Callable[[Progress], None] | None) – Receives updates for each stage.

• cancel (CancelToken | None) – Stops the install.

Returns:

The installed version id.

Return type:

str

expected_id() → str | None

Return the version id this loader should have, without any network use.

Returns:

The version id, or None if it cannot be known in advance. That is the default, and version_id is used instead.

Return type:

str | None

is_installed(

game: GameDir,

*,

session: Session | None = None,

cache_dir: Path | None = None,

) → bool

Return whether this loader is already installed in game.

The built-in loaders answer this from local files, with no network use.

Parameters:

• game (GameDir) – The game directory.

• session (Session | None) – The session to use, if the loader has to ask a service.

• cache_dir (Path | None) – The cache directory. Defaults to the per-user cache.

Returns:

True if its version JSON exists.

Return type:

bool