Solr - How to get search result in specific format

Question

While exploring example for indexing wikipedia data in Solr, how can we get the expected result (i.e. same as data imported)?

Is there any process that we can achieve it through configurations not from group query, because I have data which having lots of inner tags.

I explored xslt result transformation, but i am looking for json response.

imported doc:

<page>
<title>AccessibleComputing</title>
    <ns>0</ns>
    <id>10</id>
    <redirect title="Computer accessibility" />
    <revision>
    <id>381202555</id>
    <parentid>381200179</parentid>
    <timestamp>2010-08-26T22:38:36Z</timestamp>
    <contributor>
         <username>OlEnglish</username>
         <id>7181920</id>
    </contributor>
</revision>
</page>

solrConfig.xml:

<dataConfig>
        <dataSource type="FileDataSource" encoding="UTF-8" />
        <document>
        <entity name="page"
                processor="XPathEntityProcessor"
                stream="true"
                forEach="/mediawiki/page/"
                url="data/enwiki-20130102-pages-articles.xml"
                transformer="RegexTransformer,DateFormatTransformer"
                >
            <field column="id"        xpath="/mediawiki/page/id" />
            <field column="title"     xpath="/mediawiki/page/title" />
            <field column="revision"  xpath="/mediawiki/page/revision/id" />
            <field column="user"      xpath="/mediawiki/page/revision/contributor/username" />
            <field column="userId"    xpath="/mediawiki/page/revision/contributor/id" />
            <field column="text"      xpath="/mediawiki/page/revision/text" />
            <field column="timestamp" xpath="/mediawiki/page/revision/timestamp" dateTimeFormat="yyyy-MM-dd'T'hh:mm:ss'Z'" />
            <field column="$skipDoc"  regex="^#REDIRECT .*" replaceWith="true" sourceColName="text"/>
       </entity>
       </document>
</dataConfig>

Response by solr query:

  "response": {
    "numFound": 1,
    "start": 0,
    "docs": [
      {
        "id": "10",
        "timestamp": "2010-08-26T17:08:36Z",
        "revision": 381202555,
        "titleText": "AccessibleComputing",
        "userId": 7181920,
        "user": "OlEnglish"
      }
    ]
  }

expected response:

"response": {
    "numFound": 1,
    "start": 0,
    "docs": [
      {
        "id": "10",
        "timestamp": "2010-08-26T17:08:36Z",
        "revision": 381202555,
        "titleText": "AccessibleComputing",
        "contributor": [{
            "userId": 7181920,
            "user": "OlEnglish"
        }]
      }
    ]
  }

Answer 1

If you don't like the idea of using XsltResponseWriter (which can help int outputting the results in JSON as well), you can create your own SearchComponent, which will modify the output. When you use a custom SearchComponent you can apply different ResponseWriters to the output (xml, json, csv, xslt, etc.).

You can learn how to create a custom SearchComponent in this article, for example.

To use XsltResponseWriter, add this code to solrconfig.xml:

<queryResponseWriter name="xslt" class="org.apache.solr.response.XSLTResponseWriter"/>

Add a json.xsl file to conf/xslt folder, which has transformation rules for your XML output (when you use wt=xml in your query), something like this:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

  <xsl:strip-space elements="*"/>
  <xsl:output method="text" indent="no" media-type="application/json"/>

  <xsl:template match="result">
    <xsl:text>{"response":{"docs":[</xsl:text>
    <xsl:apply-templates select="doc"/>
    <xsl:text>]}}</xsl:text>
  </xsl:template>

  <xsl:template match="doc">
    <xsl:if test="position() &gt; 1">
      <xsl:text>,</xsl:text>
    </xsl:if>
    <xsl:text>{"contributor": [{"userId": </xsl:text><xsl:value-of select="userId"/><xsl:text>, "user": "</xsl:text><xsl:value-of select="user"/><xsl:text>"}]}</xsl:text>
  </xsl:template>

</xsl:stylesheet>

Then you can get this response using a url like:

http://localhost:8983/solr/select/?q=id:10&wt=xslt&tr=json.xsl