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In the example project, The “ReplaceUrlUpdateProcessorFactory” simply retrieves the parameters specified in the configuration (if any) and pass passes them on to the “ReplaceUrlUpdateProcessor” constructor. The “ReplaceUrlUpdateProcessor” searches for a field named as specified by the ‘source.field’ parameter (if any), if it exists, its value is extracted and will override the value of the field ‘url’. This algorithm is performed for each document about to be indexed.
Now let us see how to declare and use a custom update processor:
Each Solr core manage manages its own java libraries. Therefore, so, in order to use an Update Processor in a specific core, you will need first to add the Custom Update Processor’s Processor classes to the classpath of the target core. By compiling the example project, you will obtain a jar file named “CustomUpdateProcessor-0.0.1-SNAPSHOT.jar”. Hopefully for you, Datafari is designed to facilitate the implementation of custom update processors in its main core ‘FileShare’. So you will only need to put the jar into DATAFARI_HOME/solr/solrcloud/FileShare/lib/custom and to add read permissions on the jar file to the ‘datafari’ user.
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Datafari is configured to call each custom update processor factories specified in this file (in the order they are declared) at the very end of the update processors chain. So it This guarantees that what will do the update processors will not be override by a Datafari core code !Once that your custom update processors are actually executed, once all of the actions from the Datafari core code have already been executed.
Once this is done, you will need to restart Datafari, then push and apply the new configuration thanks to the System Configuration Manager (Zookeeper) .
Then voilà, on the next crawl, every indexed document will see have their ‘url’ replaced by the value of the field specified by the source.field parameter (if that field exists in the document)
So by Through this example, you should have understood the bases : how to use parameters for an update processor, how to use and how works a custom update processor. You can now use the example update processor to develop your own.