DynamicDSGenerator.getDataSource() - dsRequest is null

[pavo123]

Hi Isomorphic,

second parameter of DynamicDSGenerator.getDataSource() is "DSRequest dsRequest" (Docs: ...This will be null if the DataSource is not needed in the context of a DSRequest).

Please take a look at this test case (using v12.0p_2019-04-03/PowerEdition Deployment (built 2019-04-03)).

web.xml

    <!-- Rewrite default definiton with this one -->
    <servlet>
        <servlet-name>RESTHandler</servlet-name>
        <servlet-class>com.smartgwt.sample.server.listener.LMSRESTHandler</servlet-class>
       <init-param>
           <param-name>defaultDataFormat</param-name>
           <param-value>json</param-value>
       </init-param>
   </servlet>

    <servlet>
        <servlet-name>RegisterDS</servlet-name>
        <servlet-class>com.smartgwt.sample.server.listener.RegisterDS</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

LMSRESTHandler.java

package com.smartgwt.sample.server.listener;

import com.isomorphic.datasource.DSRequest;
import com.isomorphic.datasource.DSResponse;
import com.isomorphic.datasource.DataSource;
import com.isomorphic.rpc.RPCManager;
import com.isomorphic.servlet.RESTHandler;
import com.isomorphic.servlet.RequestContext;

public class LMSRESTHandler extends RESTHandler {
    private static final long serialVersionUID = -1L;

    @Override
    public void processRestTransaction(RPCManager rpcManager, RequestContext requestContext) throws Exception {
        super.processRestTransaction(rpcManager, requestContext);
    }

    @Override
    public DSResponse handleDSRequest(DSRequest dsRequest, RPCManager rpcManager, RequestContext requestContext) throws Exception {
        DSRequest request = new DSRequest("animals", DataSource.OP_FETCH, rpcManager);
        DSResponse returnResponse = request.execute();
        return returnResponse;
    }
}

RegisterDS.java

package com.smartgwt.sample.server.listener;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;

import com.isomorphic.datasource.DSRequest;
import com.isomorphic.datasource.DataSource;
import com.isomorphic.datasource.DynamicDSGenerator;

public class RegisterDS extends HttpServlet {
    private static final long serialVersionUID = 7849924835392267735L;

    @Override
    public void init() throws ServletException {
        final DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();

        DynamicDSGenerator animalsGenerator = new DynamicDSGenerator() {
            @Override
            public DataSource getDataSource(String id, DSRequest dsRequest) {
                DataSource ds = null;
                try {
                    DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
                    // Document doc = documentBuilder
                    // .parse(getServletContext().getResourceAsStream("war\\ds\\animals.ds.xml"));
                    Document doc = documentBuilder
                            .parse("C:\\Users\\Pavo\\eclipse-workspace\\lib\\smartgwtpower-12.0p\\samples\\built-in-ds\\war\\ds\\animals.ds.xml");
                    //Set a breakpoint on the next line of the code
                    ds = DataSource.fromXML(doc);
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
                return ds;
            }
        };
        DataSource.addDynamicDSGenerator(animalsGenerator, "animals");
    }
}

animals.ds.xml

<DataSource
    ID="animals"
    serverType="sql"
    tableName="animals"
    testFileName="animals.data.xml"
>
    <fields>
        <field name="commonName"      title="Animal"             type="text"/>
        <field name="scientificName"  title="Scientific Name"    type="text"  primaryKey="true"  required="true"/>
        <field name="lifeSpan"        title="Life Span"          type="integer"/>
        <field name="status"          title="Endangered Status"  type="text">
            <valueMap>
                <value>Threatened</value>
                <value>Endangered</value>
                <value>Not Endangered</value>
                <value>Not currently listed</value>
                <value>May become threatened</value>
                <value>Protected</value>
            </valueMap>
        </field>
        <field name="diet"            title="Diet"               type="text"/>
        <field name="information"     title="Interesting Facts"  type="text"  length="1000"/>
        <field name="picture"         title="Picture"            type="image" detail="true"
               imageURLPrefix="/isomorphic/system/reference/inlineExamples/tiles/images/"/>
    </fields>
<serverObject lookupStyle="new" className="com.smartgwt.sample.server.listener.Animals" />
</DataSource>

Animals.java

package com.smartgwt.sample.server.listener;

import javax.servlet.http.HttpServletRequest;

import com.isomorphic.datasource.DSRequest;
import com.isomorphic.datasource.DSResponse;
import com.isomorphic.datasource.DataSource;
import com.isomorphic.tools.DataImport;

public class Animals {
    public DSResponse fetch(DSRequest dsRequest, HttpServletRequest servletRequest) throws Exception {
        DataImport dataImporter = new DataImport();
        dataImporter.setPopulateDisplayFields(true);

        DSRequest addRequest = new DSRequest("animals", DataSource.OP_ADD, dsRequest.getRPCManager());
        //Set a breakpoint on the next line of the code
        addRequest.setValues(dataImporter.importDataSourceRecord(dsRequest.getValues(), dsRequest.getDataSourceName()));
        DSResponse addResponse = addRequest.execute();

        return addResponse;
    }
}

Call:

http://127.0.0.1:8888/builtinds/sc/RESTHandler/employees

If you set a breakpoint in both places where I wrote in the comments, after execution of

addRequest.setValues (dataImporter.importDataSourceRecord (dsRequest.getValues (), dsRequest.getDataSourceName ()));

in Animals.java, "animalsGenerator" is called again but "dsRequest" is null. I don't see a reason why "dsRequest" is null at this point so this could be a bug.

My actual case is a way more complicated but I hope you see the problem.

Best regards
Pavo

[Isomorphic]

Your call to DataImport performs a DataSource operation, and since it is not passed a DataSource, it needs to retrieve one, and since it is not passed a DSRequest, there's no way it can provide a DSRequest when the DataSource is being generated.

This isn't a bug per se, but it's true that right now there's no signature on DataImport that would get you a DSRequest in your DynamicDSGenerator. We'll look at adding one.

[pavo123]

Hi Isomorphic,

thank you very much! That will solve my problem.

Best regards
Pavo

[Isomorphic]

We've just added a new signature of DataImport.importDataSourceRecord() in order to pass it an instance of DataSource, which should solve your issue. The new signature will be available as of tomorrow's builds (October 29th).

So, your code should now be:

addRequest.setValues(dataImporter.importDataSourceRecord(dsRequest.getValues(), dsRequest.getDataSource()));

Regards
Isomorphic Software

[pavo123]

Hi Isomorphic,

that solved my problem, thank you very much!

Best regards
Pavo