GET /datastores/{datastore_id}/datasources: Get all
            datasources within a given datastore.

def index(self, datastore_id=None):
        """ GET /datastores/{datastore_id}/datasources: Get all
            datasources within a given datastore."""
        datastore = self._get_datastore_by_id(datastore_id)
        if datastore is None:
            abort(404)
        discovery_result = discover_datasources(datastore.ogrstring)
        for datasource in discovery_result:
            datasource['href'] = h.url_for(controller="datasources", action="show", datastore_id=datastore_id, datasource_id=datasource['id'])
        # prevent JSON Array Cross-site Exploits (XSRF/CSRF)
        return {'datasources': discovery_result}