Difference between revisions of "GIS Publisher Service"
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** Streamed geospatial objects (see [[The_Streams_Library | gCube Streams Library]]) | ** Streamed geospatial objects (see [[The_Streams_Library | gCube Streams Library]]) | ||
** GISFile (i.e. CSquareCode CSV File, NetCDF etc.) | ** GISFile (i.e. CSquareCode CSV File, NetCDF etc.) | ||
+ | |||
+ | The following snippet shows how to publish a stream of geospatial objects (in this case cSquarePoints) | ||
+ | |||
+ | <source lang="java"> | ||
+ | //Static import according to CL conventions | ||
+ | |||
+ | import static org.gcube.data.publishing.gis.publisher.client.plugins.AbstractPlugin.publisher; | ||
+ | .... | ||
+ | |||
+ | |||
+ | //The actual execution code | ||
+ | |||
+ | Publisher publisher=publisher().build(); | ||
+ | final ResultWrapper<CSquarePoint> rs=new ResultWrapper<CSquarePoint>(GCUBEScope.getScope(<SCOPE>)); | ||
+ | Thread t=new Thread(){ | ||
+ | @Override | ||
+ | public void run() { | ||
+ | try { | ||
+ | for(...){ | ||
+ | // Read and instantiate points from file or other source | ||
+ | rs.add(toSendPoint); | ||
+ | } | ||
+ | }catch(...){ | ||
+ | }finally{ | ||
+ | rs.close(); | ||
+ | } | ||
+ | } | ||
+ | }; | ||
+ | |||
+ | Stream<CSquarePoint> stream=pipe(convert(new URI(rs.getLocator())).of(GenericRecord.class).withDefaults()).through(new ResultGenerator<CSquarePoint>()); | ||
+ | t.start(); | ||
+ | |||
+ | // Generate Style configuration | ||
+ | |||
+ | StyleGenerationRequest styleReq=new StyleGenerationRequest(); | ||
+ | .... | ||
+ | |||
+ | // Generate Layer configuration | ||
+ | |||
+ | LayerGenerationRequest layerReq= new LayerGenerationRequest(); | ||
+ | .... | ||
+ | |||
+ | // RequestConfiguration Object to be passed along streamed data | ||
+ | |||
+ | GISRequestConfiguration config=new GISRequestConfiguration(); | ||
+ | config.setRepositoryDestination(GISRepositoryType.GEOSERVER); | ||
+ | ... | ||
+ | config.getToGenerateLayers().add(layerReq); | ||
+ | config.getToGenerateStyles().add(styleReq); | ||
+ | |||
+ | // Sending syncronous publish request | ||
+ | |||
+ | PublishingReport report=publisher.publishData(new StreamedGISData<CSquarePoint>(stream, CSquarePoint.class), config); | ||
+ | |||
+ | System.out.println(report); | ||
+ | |||
+ | </source> | ||
==GIS Publisher Framework Library== | ==GIS Publisher Framework Library== | ||
=== Implementing a plugin === | === Implementing a plugin === | ||
=== Available plugins === | === Available plugins === |
Revision as of 16:04, 8 May 2013
The GIS Publisher service manages geospatial data and metadata in a gCube based infrastructure. It relies on the gCube information system to gather information on which platforms are available in the current scope, balancing the load between the different platform instances. Its goal is to deal with the heterogeneous GIS platforms offering a common interface to other gCube services / application which need to publish geospatial data. Since each platform has a different approach on how to manage data, the GIS Publisher service is designed as a pluggable service, delegating to each plugin the platform specific interaction to third party software. Other than abstracting from specific GIS platform implementations, the GIS Publisher balances the load between the platform instances, and manages the replicas of the same services.
Overall Design
Applications which need to publish geospatial data can interact with the service via the [GIS Publisher CL]. A GISRequestConfiguration object is sent to the service, specifying :
- The GISData to publish
- The destination platform type
- Information to generate layers
The service enqueues every received request, assigning it a unique identifier. When a request is handled, the appropriate plugin is selected and invoked. At the end of the process a publish operation object is returned to the client, reporting information on :
- Published data references
- Published metadata
- Error messages (in case some of the operations fail)
CSquare codes Handling
CSquare codes referenced data are commonly used in geospatial applications, but they are not ready to be stored and published on GISServices as geospatial data. In fact they need to be coupled with appropriate geometries. Since this is a common logic in publishing csquarecoded data, the GISPublisher itself implement this, offering facilities to transform these data to the various plugins. The CSquareCodeDB is a postgis database containing various tables, each one representing csquarecodes as geometries in different resolutions.
Modules
The service is distributed as a set of maven artifacts:
- org.gcube.data.publishing.gis-publisher, parent for service and stubs implementation.
- org.gcube.data.publishing.gis-publisher-service, service implementation.
- org.gcube.data.publishing.gis-publisher-stubs, service stubs.
- org.gcube.data.publishing.gis-publisher-plugin-framework, library with common data model and plugin interfaces definition.
- org.gcube.data.publishgin.gis-publisher-client-library, client library to interact with the service.
GIS Publisher CL
Client library is developed on top of gCube CL Framework. It exposes synchronous and asynchronous methods to interact with the service.
Publising data
To publish data, callers need to specify two objects:
- GISRequestConfiguration object : among the other information, this object states
- destination platform type (i.e GeoServer,THREDDS)
- to generate styles definition : styles to generate prior layer generation
- to generate layers definition : information to publish layers based on the passed data
- GISData object : the actual data to publish, it can be one of the following types
- Streamed geospatial objects (see gCube Streams Library)
- GISFile (i.e. CSquareCode CSV File, NetCDF etc.)
The following snippet shows how to publish a stream of geospatial objects (in this case cSquarePoints)
//Static import according to CL conventions import static org.gcube.data.publishing.gis.publisher.client.plugins.AbstractPlugin.publisher; .... //The actual execution code Publisher publisher=publisher().build(); final ResultWrapper<CSquarePoint> rs=new ResultWrapper<CSquarePoint>(GCUBEScope.getScope(<SCOPE>)); Thread t=new Thread(){ @Override public void run() { try { for(...){ // Read and instantiate points from file or other source rs.add(toSendPoint); } }catch(...){ }finally{ rs.close(); } } }; Stream<CSquarePoint> stream=pipe(convert(new URI(rs.getLocator())).of(GenericRecord.class).withDefaults()).through(new ResultGenerator<CSquarePoint>()); t.start(); // Generate Style configuration StyleGenerationRequest styleReq=new StyleGenerationRequest(); .... // Generate Layer configuration LayerGenerationRequest layerReq= new LayerGenerationRequest(); .... // RequestConfiguration Object to be passed along streamed data GISRequestConfiguration config=new GISRequestConfiguration(); config.setRepositoryDestination(GISRepositoryType.GEOSERVER); ... config.getToGenerateLayers().add(layerReq); config.getToGenerateStyles().add(styleReq); // Sending syncronous publish request PublishingReport report=publisher.publishData(new StreamedGISData<CSquarePoint>(stream, CSquarePoint.class), config); System.out.println(report);