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The Heliophysics Data Application Programmer’s Interface (HAPI) specification is a time series download and streaming format specification. A 1-page summary is given in HAPI_OnePager.pdf. A more detailed overview is given in the JGR article Weigel et al., 2021 and the presentation by Vandegriff et al. (pdf|YouTube video).
The HAPI specification was recommended by COSPAR in 2018 as the common data access API for space science and space weather data.
A list of HAPI-compliant data servers is available at http://hapi-server.org/servers/.
The hapi-server GitHub project contains a collection of repositories for HAPI–related software and documentation, including client and server libraries and code for verifying and testing a HAPI server.
Use the interface at http://hapi-server.org/servers/ to download data from your browser, generate ~10-line wget/curl/IDL/MATLAB/Python scripts to download data, or create preview plots.
A demonstration of using 5 different clients to access data from a HAPI server is shown in a YouTube video.
All software related to the HAPI specification is available from its GitHub project page. Software includes clients, servers, and a server verifier/validator.
The HAPI specification describes a minimum set of capabilities needed for a server to allow access to the time series data values within one or more data collections.
Prior to writing server-side software, we suggest trying the generic stand-alone HAPI server. If you can generate HAPI ASCII of your datasets with a command line program, you can use this server to quickly get a HAPI-compliant server running on your site.
User-contributed source code for servers in various languages is available at at GitHub. This contributed code is typically not up-to-date or generalized but it may be useful for getting started.
See the server-ui repository for a basic server entry/overview page template for a HAPI server. Code is also available for a web interface for generating URLs to download data, plotting data from a HAPI server, and generating scripts that read and plot the selected parameter (the code used by http://hapi-server.org/servers/).
Server developers can test their server for HAPI-compliance using the HAPI server verification service.
If you have developed a HAPI server and it is ready for production and would like to make it automatically visible to existing software in the HAPI ecosystem, see https://github.com/hapi-server/servers