Add Apache Solr-Based Indexing

WSO2 API Manager has Apache Solr based indexing for API documentation content. It provides both the API Publisher and Store a full-text search facility to search through the API documentation, and find the documents and related APIs. The search syntax is doc:keyword. The search criteria looks for the keyword in any word/phrase in the documentation content and returns both the matching documents and associated APIs.

The following media types have Apache Solr based indexers by default, which are configured using the <Indexers> element in <APIM_HOME>/repository/conf/registry.xml file.

Text : text/plain
PDF : application/pdf
MS word : application/msword
MS Powerpoint : application/vnd.ms-powerpoint
MS Excel : application/vnd.ms-excel
XML : application/xml

Writing a custom index

In addition to the default indexes, you can write your own indexer implementation and register it as follows:

Write a custom indexer.
The following is the sample indexer code.

package org.wso2.indexing.sample;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Arrays;
import org.apache.solr.common.SolrException;
import org.wso2.carbon.registry.core.exceptions.RegistryException;
import org.wso2.carbon.registry.core.utils.RegistryUtils;
import org.wso2.carbon.registry.indexing.IndexingConstants;
import org.wso2.carbon.registry.indexing.AsyncIndexer.File2Index;
import org.wso2.carbon.registry.indexing.indexer.Indexer;
import org.wso2.carbon.registry.indexing.solr.IndexDocument;

public class PlainTextIndexer implements Indexer {
    public IndexDocument getIndexedDocument(File2Index fileData) throws SolrException,
            RegistryException {
             
             /* Create index document with resource path and raw content*/
             IndexDocument indexDoc = new IndexDocument(fileData.path, RegistryUtils.decodeBytes(fileData.data), null);
             
             /* You can specify required field/value pairs for this indexing document.
              * When searching we can query on these fields  */
             Map<String, List<String>> fields = new HashMap<String, List<String>>();
             fields.put("path", Arrays.asList(fileData.path));
                                     
             if (fileData.mediaType != null) {
                         fields.put(IndexingConstants.FIELD_MEDIA_TYPE, Arrays.asList(fileData.mediaType));
             } else {
                         fields.put(IndexingConstants.FIELD_MEDIA_TYPE, Arrays.asList("text/plain"));
             }
             
             /* set fields for index document*/
             indexDoc.setFields(fields);             
             return indexDoc;
    }    
}

Add the custom indexer JAR file to the <API-M_HOME>/repository/components/lib directory.
Update the <Indexers> element in the <API-M_HOME>/repository/conf/registry.xml file with the new indexer.
The content is indexed using this media type. For example,
```
<indexers>
     <indexer class="org.wso2.indexing.sample.PlainTextIndexer" mediaTypeRegEx="text/plain" profiles="default,api-store,api-publisher"/>
</indexers>
```
The attributes of the above configuration are described below:
class Java class name of the indexer.
mefiaTypeRegEx A regular expression (regex) pattern to match the media type.
profiles API-M profiles in which the indexer is available.
Restart the server.
Add the API documentation using the new media type and thereafter search some term in the documentation using the syntax (doc:keyword).
You can now see how the documentation has got indexed according to the media type.

`class`	Java class name of the indexer.
`mefiaTypeRegEx`	A regular expression (regex) pattern to match the media type.
`profiles`	API-M profiles in which the indexer is available.