add hf_xet as an optional dependency

setup.py

@@ -55,6 +55,7 @@ def get_version() -> str:
     "keras<3.0",
 ]
 
+extras["hf_xet"] = ["hf_xet"]
 
 extras["testing"] = (
     extras["cli"]

src/huggingface_hub/constants.py

@@ -233,3 +233,15 @@ def _as_int(value: Optional[str]) -> Optional[int]:
     "stanza",
     "timm",
 ]
+
+# Xet constants
+
+# TODO: xetpoc - change this to the production endpoint
+_XET_CAS_DEFAULT_SANDBOX_ENDPOINT = "http://cas-server.us.dev.moon.huggingface.tech/"
+XET_ENDPOINT = os.getenv("HF_XET_CAS_ENDPOINT") or _XET_CAS_DEFAULT_SANDBOX_ENDPOINT
+
+HUGGINGFACE_HEADER_X_XET_ENDPOINT = "X-Xet-Cas-Url"
+HUGGINGFACE_HEADER_X_XET_ACCESS_TOKEN = "X-Xet-Access-Token"
+HUGGINGFACE_HEADER_X_XET_EXPIRATION = "X-Xet-Token-Expiration"
+HUGGINGFACE_HEADER_X_XET_HASH = "X-Xet-Hash"
+HUGGINGFACE_HEADER_X_XET_REFRESH_ROUTE = "X-Xet-Refresh-Route"

src/huggingface_hub/utils/_runtime.py

@@ -151,6 +151,15 @@ def get_hf_transfer_version() -> str:
     return _get_version("hf_transfer")
 
 
+# xet
+def is_xet_available() -> bool:
+    return is_package_available("hf_xet")
+
+
+def get_xet_version() -> str:
+    return _get_version("hf_xet")
+
+
 # keras
 def is_keras_available() -> bool:
     return is_package_available("keras")
@@ -357,6 +366,7 @@ def dump_environment_info() -> Dict[str, Any]:
     info["numpy"] = get_numpy_version()
     info["pydantic"] = get_pydantic_version()
     info["aiohttp"] = get_aiohttp_version()
+    info["hf_xet"] = get_xet_version()
 
     # Environment variables
     info["ENDPOINT"] = constants.ENDPOINT