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Introduction

On Data Store Server (DSS) aggregation/ingestion services based on Jython scripts can be used to extend openBIS by custom services. These services have full access on data store and Application Server (AS).

Often only access on AS is needed. Going over DSS is a detour. For such cases it is better to write an AS core plugin of type services.

How to write a custom AS service core plugin

Here is the recipe to create an AS core plugin of type services:

  1. The folder <core plugin folder>/<module>/<version>/as/services/<core plugin name> has to be created.
  2. In this folder two files have to be created: plugin.properties and script.py. The properties file should contain:

    plugin.properties
    class = ch.ethz.sis.openbis.generic.server.asapi.v3.helper.service.JythonBasedCustomASServiceExecutor
    script-path = script.py
  3. The script file should have the function process with two arguments. The first argument is the context. It contains the methods getSessionToken() and getApplicationService() which returns an instance of ch.ethz.sis.openbis.generic.asapi.v3.IApplicationServerApi. The second argument is a map of key-value pairs. The key is a string and the values is an arbitrary object.

    Anything returned by the script will be returned to the caller of the service. Here is an example of a script which creates a space:

    script.py
    from ch.ethz.sis.openbis.generic.asapi.v3.dto.space.create import SpaceCreation
    
    def process(context, parameters):
        space_creation = SpaceCreation()
        space_creation.code = parameters.get('space_code');
        result = context.applicationService.createSpaces(context.sessionToken, [space_creation]);
        return "Space created: %s" % result

    Note, that all changes on the AS database will be done in one transaction.

How to use a custom AS service

The application API version 3 offers the following method to search for existing services:

SearchResult<CustomASService> searchCustomASServices(String sessionToken, CustomASServiceSearchCriteria searchCriteria,
            CustomASServiceFetchOptions fetchOptions)

The following Java code example returns all available services:

SearchResult<CustomASService> services = service.searchCustomASServices(sessionToken, new CustomASServiceSearchCriteria(), new CustomASServiceFetchOptions());

 

With the following method of the API version 3 a specified service can be executed:

public Object executeCustomASService(String sessionToken, ICustomASServiceId serviceId, CustomASServiceExecutionOptions options);

The serviceId can be obtained from a CustomASService object (as returned by the searchCustomASServices method) by the getter method getCode(). It can also be created as an instance of CustomASServiceCode. Note, that the service code is just the core plugin name.

Parameter bindings (i.e. key-value pairs) are specified in the CustomASServiceExecutionOptions object by invoking for each binding the method withParameter().

Here is a code example:

CustomASServiceExecutionOptions options = new CustomASServiceExecutionOptions().withParameter("space_code", "my-space");
Object result = service.executeCustomASService(sessionToken, new CustomASServiceCode("space-creator"), options);
System.out.println(result);

 

 

 

 

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