stac-asset

Download STAC Assets using a variety of authentication schemes.

Installation

python -m pip install stac-asset

To use the command-line interface (CLI):

python -m pip install 'stac-asset[cli]'

Usage

We have a Python API and a command-line interface (CLI).

API

Here's how to download a STAC Item and all of its assets to the current working directory. The correct client will be guessed from the assets' href. Each asset's href will be updated to point to the local file.

import pystac
import stac_asset
import asyncio

async def main():
    href = "https://raw.githubusercontent.com/radiantearth/stac-spec/master/examples/simple-item.json"
    item = pystac.read_file(href)
    item = await stac_asset.download_item(item, ".")
    return item

asyncio.run(main())

If you're working in a fully synchronous application, you can use our blocking interface:

import stac_asset.blocking
href = "https://raw.githubusercontent.com/radiantearth/stac-spec/master/examples/simple-item.json"
item = pystac.read_file(href)
item = stac_asset.blocking.download_item(item, ".")

Note that the above will not work in some environments like Jupyter notebooks which already have their own asyncio loop running. To get around this, you can use nest_asyncio. Simply run the following before using any functions from stac_asset.blocking.

import nest_asyncio
nest_asyncio.apply()

CLI

To download an item using the command line:

stac-asset download \
    https://raw.githubusercontent.com/radiantearth/stac-spec/master/examples/simple-item.json

To download all assets from the results of a pystac-client search, and save the item collection to a file named item-collection.json:

stac-client search https://planetarycomputer.microsoft.com/api/stac/v1 \
        -c landsat-c2-l2 \
        --max-items 1 | \
    stac-asset download > item-collection.json

If you'd like to only download certain assets, e.g. a preview image, you can use the include -i flag:

stac-client search https://planetarycomputer.microsoft.com/api/stac/v1 \
        -c landsat-c2-l2 \
        --max-items 1 | \
    stac-asset download -i rendered_preview -q

By default, all assets are stored in a folder named after the item ID. To change this, you can use the -p flag and specify a path template using PySTAC layout template variables:

stac-client search https://planetarycomputer.microsoft.com/api/stac/v1 \
        -c landsat-c2-l2 \
        --max-items 1 | \
    stac-asset download -i rendered_preview -p '${collection}'

See the documentation for more examples and complete API and CLI documentation.

Clients

This library comes with several clients, each tailored for a specific data provider model and authentication scheme. Some clients require some setup before use; they are called out in this table, and the details are provided below.

Name	Description	Notes
HttpClient	Simple HTTP client without any authentication
S3Client	Simple S3 client	Use requester_pays=True in the client initializer to enable access to requester pays buckets, e.g. USGS landsat's public AWS archive
FilesystemClient	Moves files from place to place on a local filesystem	Mostly used for testing
PlanetaryComputerClient	Signs urls with the Planetary Computer Authentication API	No additional setup required, works out of the box
EarthdataClient	Uses a token-based authentication to download data, from some Earthdata providers, e.g. DAACs	Requires creation of a personal access token, see docs

For information about configuring each client, see the API documentation for that client.

Versioning

This project does its best to adhere to semantic versioning. Any module, class, constant, or function that does not begin with a _ is considered part of our public API for versioning purposes. Our command-line interface (CLI) is NOT considered part of our public API, and may change in breaking ways at any time. If you need stability promises, use our API.

Contributing

Use Github issues to report bugs and request new features. Use Github pull requests to fix bugs and propose new features.

Developing

Install uv. Then clone, sync, and install pre-commit:

git clone [email protected]:stac-utils/stac-asset.git
cd stac-asset
uv sync
pre-commit install

Testing

Some network-touching tests are disabled by default. To enable these tests:

uv run pytest --network-access

Some tests are client-specific and need your environment to be configured correctly. See each client's documentation for instructions on setting up your environment for each client.

Docs

To build:

make -C docs html && open docs/_build/html/index.html

It can be handy to use sphinx-autobuild if you're doing a lot of doc work:

uv pip install sphinx-autobuild
sphinx-autobuild --watch src docs docs/_build/html

License

Apache-2.0