HAPI Client for Python

Basic usage examples for various HAPI servers are given in hapi_demo.py. See also

Examples section of a Jupyter Notebook hosted on Google Colab: .
PyHC Summer School tutorials

Installation

pip install hapiclient --upgrade
# or
pip install 'git+https://github.com/hapi-server/client-python' --upgrade

The optional hapiplot package provides basic preview plotting capabilities of data from a HAPI server. The Plotting section of the hapiclient Jupyter Notebook shows how to plot the output of hapiclient using many other plotting libraries.

To install hapiplot, use

python -m pip install hapiplot --upgrade
# or
python -m pip install 'git+https://github.com/hapi-server/plot-python' --upgrade

See the Appendix for a fail-safe installation method.

Basic Example

# Get Dst index from CDAWeb HAPI server
from hapiclient import hapi

# See http://hapi-server.org/servers/ for a list of
# other HAPI servers and datasets.
server     = 'https://cdaweb.gsfc.nasa.gov/hapi'
dataset    = 'OMNI2_H0_MRG1HR'
start      = '2003-09-01T00:00:00'
stop       = '2003-12-01T00:00:00'
parameters = 'DST1800'
opts       = {'logging': True}
# See misc/hapi_logging_demo.py for example of using conventional Python logging.

# Get data
data, meta = hapi(server, dataset, parameters, start, stop, **opts)
print(meta)
print(data)

# Plot all parameters
from hapiplot import hapiplot
hapiplot(data, meta)

Documentation

Basic usage examples for various HAPI servers are given in hapi_demo.py and the Examples section of a Jupyter Notebook hosted on Google Colab.

See http://hapi-server.org/servers/ for a list of HAPI servers and datasets.

All of the features are extensively demonstrated in hapi_demo.ipynb, a Jupyter Notebook that can be viewed an executed on Google Colab.

Metadata Model

See also the examples in the Metadata Model section of the hapiclient Jupyter Notebook.

The HAPI client metadata model is intentionally minimal and closely follows that of the HAPI metadata model. We expect that another library will be developed that allows high-level search and grouping of information from HAPI servers. See also issue #106.

Data Model and Time Format

See also the examples in the Data Model section of the hapiclient Jupyter Notebook. The examples include

Fast and well-tested conversion from ISO 8601 timestamp strings to Python datetime objects
Putting the content of data in a Pandas DataFrame object
Creating an Astropy NDArray

A request for data of the form

data, meta = hapi(server, dataset, parameters, start, stop)

returns the Numpy N-D array data and a Python dictionary meta from a HAPI-compliant data server server. The structure of data and meta mirrors the structure of a response from a HAPI server.

The HAPI client data model is intentionally basic. There is an ongoing discussion of a data model for Heliophysics data among the PyHC community. When this data model is complete, a function that converts data and meta to that data model will be included in the hapiclient package.

Development and Testing

Testing Python versions available with tox-env

As of 2026-04-14, Python 3.8+ is available with tox-env.

git clone https://github.com/hapi-server/client-python
cd client-python; python -m pip install -e .

# Run a specific test on current Python version (default is log_level=INFO
# for hapiclient logger and test logger when executed this way).
python test/test_hapi_data_requests.py

# Run a specific test on a specific Python version with all logging
tox -e py311 -- test/test_hapi_data_requests.py
# Set log level for test logger
tox -e py311 -- test/test_hapi_data_requests.py --log-level=INFO

# Run a specific test on all Python versions set by tox.ini `envlist`
tox -- test/test_hapi_data_requests.py

# Run all tests in ./test
tox

# Run long-running tests
tox -e long-test

# Run long-running tests on a specific Python version
tox -e long-test --override testenv:long-test.basepython=python3.11

Testing Python versions available with Anaconda

As of 2026-04-14, Python 3.5+ is available with Anaconda.

git clone https://github.com/hapi-server/client-python
cd client-python; python -m pip install -e .

or, create an isolated Anaconda installation (downloads and installs latest Miniconda3) using

make install PYTHON=python3.6
# Execute command displayed to activate isolated environment

The command pip install -e . creates symlinks so that the local package is used instead of an installed package. You may need to execute python -m pip uninstall hapiclient to ensure the local package is used. To check the version installed, use python -m pip list | grep hapiclient.

To run tests before a commit, execute

make repository-test

To run an individual unit test in a Python session, use, e.g.,

cd test; python test_hapitime_reformat.py

Contact

Submit bug reports and feature requests on the repository issue tracker.

Before submitting a pull request, please post an issue with the proposed changes for discussion prior to developing the pull request.