How to use for-each element as parameter to a template - json

Question

I know the title doesn't sound too much descriptive of my problem.Let me explain further more below.
I have a java application that returns a JSON Array, my objectif is to parse this result in a String format to be used in another "C" Application, the only possible communication between these two applications is String format.
I have achieved this using XSLT by hard coding the values that I'm seeking for inside the JSON reponse and here's how i did it.
My XML is :
<?xml version="1.0" encoding="UTF-8"?>
<input>[{"media_key":"1-1UL-12528","media_value":"10 RUE DES TRELISSAC","media_type":"Courrier"},{"media_key":"2-1UL-12528","media_value":"0614263770","media_type":"SMS"}]</input>
and my XSL is :
<?xml version="1.0" encoding="UTF-8" ?>
<xsl:template match="input">
<output>
<xsl:call-template name="print-object-values">
<xsl:with-param name="string" select="."/>
</xsl:call-template>
</output>
</xsl:template>
<!-- Recupere la valeur d'une cle json String de type "key":"val" -->
<xsl:template name="get_string_json">
<xsl:param name = "json" />
<xsl:param name = "key" />
<xsl:variable name="needle">
<xsl:value-of select="concat('"', $key, '":"')" />
</xsl:variable>
<xsl:value-of select="substring-before(substring-after($json, $needle), '"')" />
</xsl:template>
<xsl:template name="print-object-values">
<xsl:param name="string"/>
<xsl:param name="sep_values" select="';'" />
<xsl:if test="contains($string,'media_key')">
<xsl:text>|</xsl:text>
<!-- Partie à modifier en récupérant les valeurs désiré par les fonctions déclarer prècedemment -->
<xsl:call-template name="get_string_json">
<xsl:with-param name="json" select="$string" />
<xsl:with-param name="key" select="'media_key'" />
</xsl:call-template>
<xsl:value-of select="$sep_values" />
<xsl:call-template name="get_string_json">
<xsl:with-param name="json" select="$string" />
<xsl:with-param name="key" select="'media_type'" />
</xsl:call-template>
<xsl:value-of select="$sep_values" />
<xsl:call-template name="get_string_json">
<xsl:with-param name="json" select="$string" />
<xsl:with-param name="key" select="'media_value'" />
</xsl:call-template>
<xsl:call-template name="print-object-values">
<xsl:with-param name="string" select="substring-after($string,'"},{')"/>
</xsl:call-template>
</xsl:if>
</xsl:template>
in my print-object-values template, I use print-object-values to get the value of a specific key in the JSON String.
What i want to do is instead of hard-coding the string that i'm searching for, is there a way to implement this in a variable as a map and then use it in a for-each loop to execute get_string_json ?
EDIT :
here's an example of what i want to achieve
<xsl:template match="input">
<output>
<xsl:variable name="values"> <!-- declaration of the values to search for -->
<value>
<param>media_key</param>
<param>media_type</param>
<param>media_value</param>
</value>
</xsl:variable>
<xsl:call-template name="print-object-values">
<xsl:with-param name="string" select="."/>
</xsl:call-template>
</output>
</xsl:template>
<xsl:template name="get_string_json">
<xsl:param name = "json" />
<xsl:param name = "key" />
<xsl:variable name="needle">
<xsl:value-of select="concat('"', $key, '":"')" />
</xsl:variable>
<xsl:value-of select="substring-before(substring-after($json, $needle), '"')" />
</xsl:template>
<xsl:template name="print-object-values">
<xsl:param name="string"/>
<xsl:param name="sep_values" select="';'" />
<xsl:if test="contains($string,'media_key')">
<xsl:text>|</xsl:text>
<xsl:for-each select= ><!-- select params in the variable values -->
<xsl:call-template name="get_string_json">
<xsl:with-param name="json" select="$string" />
<xsl:with-param name="key" select="" /><!-- pass the value of the param -->
</xsl:call-template>
</xsl:for-each>
<xsl:call-template name="print-object-values">
<xsl:with-param name="string" select="substring-after($string,'"},{')"/>
</xsl:call-template>
</xsl:if>
</xsl:template>

Answer 1

IMPORTANT:
The purpose of this answer is to address only this part of your question:
instead of hard-coding the string that i'm
searching for, is there a way to implement this in a variable as a map
and then use it in a for-each loop to execute get_string_json ?
I found it necessary to make some adjustments to other parts of your XSLT, but I did not examine your method of parsing the JSON.
XSLT 1.0
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:exsl="http://exslt.org/common"
extension-element-prefixes="exsl">
<xsl:output method="xml" encoding="UTF-8" indent="yes" />
<!-- declaration of the values to search for -->
<xsl:variable name="keys">
<key>media_key</key>
<key>media_type</key>
<key>media_value</key>
</xsl:variable>
<xsl:template match="input">
<output>
<xsl:call-template name="print-object-values">
<xsl:with-param name="string" select="."/>
</xsl:call-template>
</output>
</xsl:template>
<xsl:template name="print-object-values">
<xsl:param name="string"/>
<xsl:param name="separator" select="'"},{'" />
<xsl:variable name="object" select="substring-before(concat($string, $separator), $separator)" />
<xsl:text>|</xsl:text>
<!-- HERE IS THE RELEVANT PART -->
<xsl:for-each select="exsl:node-set($keys)/key">
<xsl:call-template name="get_string_json">
<xsl:with-param name="json" select="concat($object, '"')" />
<xsl:with-param name="key" select="." />
</xsl:call-template>
<xsl:if test="position()!=last()">
<xsl:text>;</xsl:text>
</xsl:if>
</xsl:for-each>
<xsl:if test="contains($string, $separator)">
<xsl:call-template name="print-object-values">
<xsl:with-param name="string" select="substring-after($string, $separator)"/>
</xsl:call-template>
</xsl:if>
</xsl:template>
<!-- Recupere la valeur d'une cle json String de type "key":"val" -->
<xsl:template name="get_string_json">
<xsl:param name = "json" />
<xsl:param name = "key" />
<xsl:variable name="needle">
<xsl:value-of select="concat('"', $key, '":"')" />
</xsl:variable>
<xsl:value-of select="substring-before(substring-after($json, $needle), '"')" />
</xsl:template>
</xsl:stylesheet>