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Prototype HAPI Web Services

The Heliophysics Application Programming Interface (HAPI) provides a standard way to access Heliophysics data. See the HAPI Specification for more details. Client software to access a HAPI server is available here.

This implementation provides access to a subset of the data available from CDAWeb and SSCWeb.

Note

The official, HAPI-compliant implementation for CDAWeb data is available https://cdaweb.gsfc.nasa.gov/hapi. That is the implementation most people should use.

Description

...

Network Protocol Support

The following web services are currently available over HTTPS and over both IPv4 and IPv6. Additional information about accessing these web services over HTTPS is available at HTTPS SPDF web services.

Example Requests

• about
• capabilities
• catalog
• info for ACE Magnetic Field 16-Second Level 2 Data.
• info for RBSP A satellite position and magnetic field model information.
• data for ACE Magnetic Field 16-Second Level 2 Data (variable-oriented JSON).
• data for ACE Magnetic Field 16-Second Level 2 Data (record-oriented JSON).
• data for Polar Fast Plasma Analyzer 13.8 second Resolution Electron Differential Energy Flux Data.
• data for Geotail satellite position and magnetic field model information (SSC).

IDL Example

An example IDL program that calls these web services is available at hapicdawebexample.pro.

jQuery Example

An example jQuery client that calls these web services is available at client.

Known Issues

The following are some of the known issues/limitations with the current implementation:

1. This is a prototype implementation which may change or be eliminated at any time.
2. Only CDAWeb and SSCWeb datasets that are sufficiently described by Space Physics Archive Search and Extract (SPASE) descriptions in the Heliophysic Data Portal (HDP) database are available.
   1. Generic NumericalData descriptions that represent multiple CDAWeb datasets will not be available. That is, an HDP dataset identified by a single spase:ResourceID cannot be associated with multiple CDAWeb datasets. Such NumericalData descriptions will not be included in the HAPI catalog.
   2. This implementation is optimized for SSCWeb datasets whose SPASE descriptions were automatically generated from responses from the SSC Web services. Such SSC SPASE descriptions contain a comment after the <Description> element stating Automatically generated from SSC on date. SSC SPASE descriptions produced by other means may not work as well.
3. The metadata returned by info and data may be different. The difference is due to the info values coming from SPASE descriptions of the data which may not be accurate. The values returned by a data request are more accurate because they come from the data itself.
4. The only format currently supported in a data response is JSON. The three data JSON formats (x_spdf_json, x_json1 and x_json2) do not conform to the HAPI specification. This implementation is unlikely to ever support the HAPI JSON format since its JSON has no corresponding XML representation and this implementation is fundamentally XML based. CSV may be supported in the future if a missing feature in a third-party serialization library is ever implemented. Binary is unlikely to ever be supported.
5. This implementation supports application/json and application/xml representations for all responses. Additionally, /info supports a text/html response representation. The representation used is based upon the HTTP Accept header value in the request. application/json is the default if the request lacks an Accept header.

Questions/Comments

Questions or comments concerning these Web services should be sent to HAPI Feedback.