Send user_agent in HEAD calls (#1854)

* Send user_agent in HEAD calls + add get_hf_file_metadata to HfApi + test

* docstring

src/huggingface_hub/file_download.py

@@ -75,6 +75,7 @@
     tqdm,
     validate_hf_hub_args,
 )
+from .utils._deprecation import _deprecate_method
 from .utils._headers import _http_user_agent
 from .utils._runtime import _PY_VERSION  # noqa: F401 # for backward compatibility
 from .utils._typing import HTTP_METHOD_T
@@ -345,6 +346,7 @@ def filename_to_url(
     return url, etag
 
 
+@_deprecate_method(version="0.22.0", message="Use `huggingface_hub.utils.build_hf_headers` instead.")
 def http_user_agent(
     *,
     library_name: Optional[str] = None,
@@ -1249,6 +1251,9 @@ def hf_hub_download(
                     token=token,
                     proxies=proxies,
                     timeout=etag_timeout,
+                    library_name=library_name,
+                    library_version=library_version,
+                    user_agent=user_agent,
                 )
             except EntryNotFoundError as http_error:
                 # Cache the non-existence of the file and raise
@@ -1595,6 +1600,9 @@ def get_hf_file_metadata(
     token: Union[bool, str, None] = None,
     proxies: Optional[Dict] = None,
     timeout: Optional[float] = DEFAULT_REQUEST_TIMEOUT,
+    library_name: Optional[str] = None,
+    library_version: Optional[str] = None,
+    user_agent: Union[Dict, str, None] = None,
 ) -> HfFileMetadata:
     """Fetch metadata of a file versioned on the Hub for a given url.
 
@@ -1612,12 +1620,20 @@ def get_hf_file_metadata(
             `requests.request`.
         timeout (`float`, *optional*, defaults to 10):
             How many seconds to wait for the server to send metadata before giving up.
+        library_name (`str`, *optional*):
+            The name of the library to which the object corresponds.
+        library_version (`str`, *optional*):
+            The version of the library.
+        user_agent (`dict`, `str`, *optional*):
+            The user-agent info in the form of a dictionary or a string.
 
     Returns:
         A [`HfFileMetadata`] object containing metadata such as location, etag, size and
         commit_hash.
     """
-    headers = build_hf_headers(token=token)
+    headers = build_hf_headers(
+        token=token, library_name=library_name, library_version=library_version, user_agent=user_agent
+    )
     headers["Accept-Encoding"] = "identity"  # prevent any compression => we want to know the real size of the file
 
     # Retrieve metadata

src/huggingface_hub/hf_api.py

@@ -92,6 +92,7 @@
 )
 from .constants import (
     DEFAULT_ETAG_TIMEOUT,
+    DEFAULT_REQUEST_TIMEOUT,
     DEFAULT_REVISION,
     DISCUSSION_STATUS,
     DISCUSSION_TYPES,
@@ -106,10 +107,7 @@
     DiscussionStatusFilter,
     DiscussionTypeFilter,
 )
-from .file_download import (
-    get_hf_file_metadata,
-    hf_hub_url,
-)
+from .file_download import HfFileMetadata, get_hf_file_metadata, hf_hub_url
 from .repocard_data import DatasetCardData, ModelCardData, SpaceCardData
 from .utils import (  # noqa: F401 # imported for backward compatibility
     BadRequestError,
@@ -4614,6 +4612,48 @@ def delete_folder(
             parent_commit=parent_commit,
         )
 
+    @validate_hf_hub_args
+    def get_hf_file_metadata(
+        self,
+        *,
+        url: str,
+        token: Union[bool, str, None] = None,
+        proxies: Optional[Dict] = None,
+        timeout: Optional[float] = DEFAULT_REQUEST_TIMEOUT,
+    ) -> HfFileMetadata:
+        """Fetch metadata of a file versioned on the Hub for a given url.
+
+        Args:
+            url (`str`):
+                File url, for example returned by [`hf_hub_url`].
+            token (`str` or `bool`, *optional*):
+                A token to be used for the download.
+                    - If `True`, the token is read from the HuggingFace config
+                    folder.
+                    - If `False` or `None`, no token is provided.
+                    - If a string, it's used as the authentication token.
+            proxies (`dict`, *optional*):
+                Dictionary mapping protocol to the URL of the proxy passed to `requests.request`.
+            timeout (`float`, *optional*, defaults to 10):
+                How many seconds to wait for the server to send metadata before giving up.
+
+        Returns:
+            A [`HfFileMetadata`] object containing metadata such as location, etag, size and commit_hash.
+        """
+        if token is None:
+            # Cannot do `token = token or self.token` as token can be `False`.
+            token = self.token
+
+        return get_hf_file_metadata(
+            url=url,
+            token=token,
+            proxies=proxies,
+            timeout=timeout,
+            library_name=self.library_name,
+            library_version=self.library_version,
+            user_agent=self.user_agent,
+        )
+
     @validate_hf_hub_args
     def hf_hub_download(
         self,

tests/test_file_download.py

@@ -41,6 +41,7 @@
     _create_symlink,
     _get_pointer_path,
     _normalize_etag,
+    _request_wrapper,
     _to_local_dir,
     cached_download,
     filename_to_url,
@@ -388,6 +389,50 @@ def test_hf_hub_download_offline_no_refs(self):
                     cache_dir=cache_dir,
                 )
 
+    def test_hf_hub_download_with_user_agent(self):
+        """
+        Check that user agent is correctly sent to the HEAD call when downloading a file.
+
+        Regression test for #1854.
+        See https://github.com/huggingface/huggingface_hub/pull/1854.
+        """
+
+        def _check_user_agent(headers: dict):
+            assert "user-agent" in headers
+            assert "test/1.0.0" in headers["user-agent"]
+            assert "foo/bar" in headers["user-agent"]
+
+        with SoftTemporaryDirectory() as cache_dir:
+            with patch("huggingface_hub.file_download._request_wrapper", wraps=_request_wrapper) as mock_request:
+                # First download
+                hf_hub_download(
+                    DUMMY_MODEL_ID,
+                    filename=CONFIG_NAME,
+                    cache_dir=cache_dir,
+                    library_name="test",
+                    library_version="1.0.0",
+                    user_agent="foo/bar",
+                )
+                calls = mock_request.call_args_list
+                assert len(calls) == 3  # HEAD, HEAD, GET
+                for call in calls:
+                    _check_user_agent(call.kwargs["headers"])
+
+            with patch("huggingface_hub.file_download._request_wrapper", wraps=_request_wrapper) as mock_request:
+                # Second download: no GET call
+                hf_hub_download(
+                    DUMMY_MODEL_ID,
+                    filename=CONFIG_NAME,
+                    cache_dir=cache_dir,
+                    library_name="test",
+                    library_version="1.0.0",
+                    user_agent="foo/bar",
+                )
+                calls = mock_request.call_args_list
+                assert len(calls) == 2  # HEAD, HEAD
+                for call in calls:
+                    _check_user_agent(call.kwargs["headers"])
+
     def test_hf_hub_url_with_empty_subfolder(self):
         """
         Check subfolder arg is processed correctly when empty string is passed to