cached-path

A file utility library that provides a unified, simple interface for accessing both local and remote files. This can be used behind other APIs that need to access files agnostic to where they are located.

Quick links

• Documentation
• PyPI Package
• Contributing
• License

Installation

cached-path requires Python 3.7 or later.

Installing with pip

cached-path is available on PyPI. Just run

pip install cached-path

Installing from source

To install cached-path from source, first clone the repository:

git clone https://github.com/allenai/cached_path.git
cd cached_path

Then run

pip install -e .

Usage

from cached_path import cached_path

Given something that might be a URL or local path, cached_path() determines which. If it's a remote resource, it downloads the file and caches it to the cache directory, and then returns the path to the cached file. If it's already a local path, it makes sure the file exists and returns the path.

For URLs, http://, https://, s3:// (AWS S3), gs:// (Google Cloud Storage), and hf:// (HuggingFace Hub) are all supported out-of-the-box. Optionally beaker:// URLs in the form of beaker://{user_name}/{dataset_name}/{file_path} are supported, which requires beaker-py to be installed.

For example, to download the PyTorch weights for the model epwalsh/bert-xsmall-dummy on HuggingFace, you could do:

cached_path("hf://epwalsh/bert-xsmall-dummy/pytorch_model.bin")

For paths or URLs that point to a tarfile or zipfile, you can also add a path to a specific file to the url_or_filename preceeded by a "!", and the archive will be automatically extracted (provided you set extract_archive to True), returning the local path to the specific file. For example:

cached_path("model.tar.gz!weights.th", extract_archive=True)

Using custom headers for HTTP requests

You can provide custom headers for HTTP requests, which is useful for accessing private resources that require authentication:

# Using an API token for private resources (e.g. Hugging Face)
headers = {"Authorization": f"Bearer {hf_token}"}
cached_path("https://huggingface.co/api/models/private-model/resolve/main/model.bin", headers=headers)

This is particularly useful for downloading private files from services like Hugging Face, GitHub, or any other API that uses Bearer token authentication.

Cache directory

By default the cache directory is ~/.cache/cached_path/, however there are several ways to override this setting:

• set the environment variable CACHED_PATH_CACHE_ROOT,
• call set_cache_dir(), or
• set the cache_dir argument each time you call cached_path().

Team

cached-path is developed and maintained by the AllenNLP team, backed by the Allen Institute for Artificial Intelligence (AI2). AI2 is a non-profit institute with the mission to contribute to humanity through high-impact AI research and engineering. To learn more about who specifically contributed to this codebase, see our contributors page.

License

cached-path is licensed under Apache 2.0. A full copy of the license can be found on GitHub.