UpdateRequestProcessor

Solr1.3

The UpdateRequestProcessor defines how an update request is processed. By default, this converts each request into an UpdateCommand and sends it to the UpdateHandler. (see SOLR-269)

Before 1.3 is released, we should make sure this is something we want to live with publicly. It exposes the UpdateCommand family in a way I don't think it was designed for.

Configuring UpdateRequestProcessors

solrconfig.xml will load a UpdateRequestProcessors

 <updateRequestProcessorChain>                                               
    <processor class="solr.CustomUpdateRequestProcessorFactory" >
   <lst name="name">
     <str name="n1">x1</str>
     <str name="n2">x2</str>
   </lst>
  </processor>
                                    
   <processor class="solr.RunUpdateProcessorFactory" />                    
   <processor class="solr.LogUpdateProcessorFactory" />                  
 </updateRequestProcessorChain>

Implementing a conditional copyField

Here is a quick example that adds the 'cat' 'popular' if the value of 'popularity' is > 5

package my.solr;

import java.io.IOException;

import org.apache.solr.common.SolrInputDocument;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.request.SolrQueryResponse;
import org.apache.solr.update.AddUpdateCommand;
import org.apache.solr.update.processor.UpdateRequestProcessor;
import org.apache.solr.update.processor.UpdateRequestProcessorFactory;

public class ConditionalCopyProcessorFactory extends UpdateRequestProcessorFactory 
{
  @Override
  public UpdateRequestProcessor getInstance(SolrQueryRequest req, SolrQueryResponse rsp, UpdateRequestProcessor next) 
  {
    return new ConditionalCopyProcessor(next);
  }
}

class ConditionalCopyProcessor extends UpdateRequestProcessor 
{
  public ConditionalCopyProcessor( UpdateRequestProcessor next) {
    super( next );
  }
  
  @Override
  public void processAdd(AddUpdateCommand cmd) throws IOException {
    SolrInputDocument doc = cmd.getSolrInputDocument();
    
    Object v = doc.getFieldValue( "popularity" );
    if( v != null ) {
      int pop = Integer.parseInt( v.toString() );
      if( pop > 5 ) {
        doc.addField( "cat", "popular" );
      }
    }
    
    // pass it up the chain
    super.processAdd(cmd);
  }
}