JSON tips for SOLR

Below given set of configuration tips while working with Solr output as JSON

1 How to set the Solr output to JSON?
set media-type as below.
<xsl:output method="text" indent="no" media-type="application/json"/>

Below line to be added in solrconfig.xml (if multi core configuration, add below line in solrconfig.xml of each core)
<queryResponseWriter name="xslt" class="org.apache.solr.response.XSLTResponseWriter"/>

Given below a sample JSON response writer. Save it in your /core/conf/XSLT folder.
The query should have ‘&wt=xslt&tr=json.xsl’ appended to invoke the required JSON format.

2 How to disable displaying an attribute if its value is zero.
<xsl:if test="articleDate != ''">
<xsl:text>","articleDate":"</xsl:text><xsl:apply-templates
select="str[@name='articleDate']"/>
</xsl:if>

3 How to get the total number of results of search returned
If the XML/JSON returned having nodes, <result>, below expression gives the count

<xsl:variable name="count" select="result/@numFound"/>
Now print the value as
<xsl:value-of select="$count"/></xsl:text>

4 How to add a comma to JSON element except for last element
Check for the position then insert comma using below logic
<xsl:if test="position()!=last()">
<xsl:text>,</xsl:text>
</xsl:if>

5) Check for a value greater than
<xsl:if test="$count &gt; 8">
<xsl:text><xsl:value-of select="$count"/> is greater than 8</xsl:text>
</xsl:if>

6) check if a value exists,
<xsl:if test="str[@name='id']">
<xsl:text> id exists</xsl:text>
</xsl:if>