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<!-- Module User's Guide -->

<chapter>

    <title>&adminguide;</title>

    <section>
	<title>Overview</title>
	<para>
		This module allows executing JavaScript scripts from the Kamailio
		configuration file.
		It exports all KEMI functions to JavaScript in order to access the
		currently processed SIP message. These functions are named within
		the JavaScript object 'KSR'.
	</para>
	<para>
		The module is based on the Duktape JavaScript engine (http://www.duktape.org),
		which is a fast and easy to embed JavaScript interpreter. The exported API
		from Kamailio to JavaScript is documented in the wiki.
	</para>
	<para>
		The module has two JavaScript contexts:
    	<itemizedlist>
	    <listitem>
		<para>
			<emphasis>first</emphasis> is used for functions jsdt_dofile()
			and jsdt_dostring().
		</para>
	    </listitem>
	    <listitem>
		<para>
		    <emphasis>second</emphasis> is used for function jsdt_run()
			and parameter 'load'. Therefore jsdt_run() cannot execute functions
			from scripts loaded via jsdt_dofile() in config. This is kind of
			caching mode, avoiding reading file every time, but you must be sure
			you do not have something that is executed by default and requires
			access to SIP message. This environment is also used by KEMI
			framework for the config SIP routing functions.
		</para>
	    </listitem>
    	</itemizedlist>
	</para>
    </section>
    <section>
	<title>Dependencies</title>
	<section>
	    <title>&kamailio; Modules</title>
	    <para>
		The following modules must be loaded before this module:
	    	<itemizedlist>
		    <listitem>
			<para>
			    <emphasis>none</emphasis>.
			</para>
		    </listitem>
	    	</itemizedlist>
	    </para>
	</section>
	<section>
	    <title>External Libraries or Applications</title>
	    <para>
		The following libraries or applications must be installed before running
		&kamailio; with this module loaded:
	    	<itemizedlist>
		    <listitem>
			<para>
				<emphasis>libm</emphasis> - the math library (part of standard
				system libraries - it is needed to complile embedded Duktape JS
				interpreter).
			</para>
		    </listitem>
	    	</itemizedlist>
	    </para>
	</section>
    </section>
    <section>
	<title>Parameters</title>
	<section id="app_jsdt.p.load">
	    <title><varname>load</varname> (str)</title>
	    <para>
			Set the path to the JavaScript file to be loaded at startup. Then you
			can use jsdt_run(function, params) to execute a function from the
			script at runtime. If you use it for KEMI configuration,
			then it has to include the required functions.
	    </para>
	    <para>
		<emphasis>
		    Default value is <quote>null</quote>.
		</emphasis>
	    </para>
	    <example>
		<title>Set <varname>load</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("app_jsdt", "load", "/usr/local/etc/kamailio/js/myscript.js")
...
</programlisting>
	    </example>
	</section>
	<section id="app_jsdt.p.mode">
	    <title><varname>mode</varname> (int)</title>
	    <para>
			Control if the API to load JavaScript module (nodejs interface) is
			initialized or not.
	    </para>
	    <para>
		<emphasis>
		    Default value is <quote>1</quote> (initialize).
		</emphasis>
	    </para>
	    <example>
		<title>Set <varname>mode</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("app_jsdt", "mode", 0)
...
</programlisting>
	    </example>
	</section>
	</section>

    <section>
	<title>Functions</title>
 	<section id="app_jsdt.f.jsdt_dofile">
	    <title>
		<function moreinfo="none">jsdt_dofile(path)</function>
	    </title>
	    <para>
		Execute the JavaScript script stored in 'path'. The parameter can be
		a string with pseudo-variables evaluated at runtime.
	    </para>
		<example>
		<title><function>jsdt_dofile</function> usage</title>
		<programlisting format="linespecific">
...
jsdt_dofile("/usr/local/etc/kamailio/js/myscript.js");
...
</programlisting>
	    </example>
	</section>

 	<section id="app_jsdt.f.jsdt_dostring">
	    <title>
		<function moreinfo="none">jsdt_dostring(script)</function>
	    </title>
	    <para>
		Execute the JavaScript script stored in parameter. The parameter can be
		a string with pseudo-variables.
	    </para>
		<example>
		<title><function>jsdt_dostring</function> usage</title>
		<programlisting format="linespecific">
...
if(!jsdt_dostring('KSR.dbg("test message\n")'))
{
    xdbg("SCRIPT: failed to execute js script!\n");
}
...
</programlisting>
	    </example>
	</section>

	<section id="app_jsdt.f.jsdt_run">
	    <title>
		<function moreinfo="none">jsdt_run(function, params)</function>
	    </title>
	    <para>
		Execute the JS function 'func' giving params as parameters. There
		can be up to 3 string parameters. The function must exist in the
		script loaded at startup via parameter 'load'. Parameters can be
		strings with pseudo-variables that are evaluated at runtime.
	    </para>
		<example>
		<title><function>jsdt_run</function> usage</title>
		<programlisting format="linespecific">
...
if(!jsdt_run("js_append_fu_to_reply"))
{
    xdbg("SCRIPT: failed to execute js function!\n");
}
...
jsdt_run("js_funcx", "$rU", "2");
...
</programlisting>
	    </example>
	</section>

	<section id="app_jsdt.f.jsdt_runstring">
	    <title>
		<function moreinfo="none">jsdt_runstring(script)</function>
	    </title>
	    <para>
		Execute the JS script stored in parameter. The parameter can be
		a string with pseudo-variables. The script is executed in JS context
		specific to loaded JS files at startup.
	    </para>
		<example>
		<title><function>jsdt_runstring</function> usage</title>
		<programlisting format="linespecific">
...
if(!jsdt_runstring('KSR.dbg("Hello World from $fU\n")'))
{
    xdbg("failed to execute js script!\n");
}
...
</programlisting>
	    </example>
	</section>

    </section>

    <section>
        <title>RPC Commands</title>
        <section id="app_jsdt.r.reload">
            <title>
            <function moreinfo="none">app_jsdt.reload</function>
            </title>
            <para>
            Marks the need to reload the js script.
            The actual reload is done by every working process when the next
            call to jsdt_run() function or KEMI config is executed.
            </para>
            <para>
            Name: <emphasis>app_jsdt.reload</emphasis>
            </para>
            <para>Parameters: <emphasis>none</emphasis></para>
            <para>
            Example:
            </para>
            <programlisting  format="linespecific">
...
&kamcmd; app_jsdt.reload
...
            </programlisting>
        </section>
       <section id="app_jsdt.r.api_list">
            <title>
            <function moreinfo="none">app_jsdt.api_list</function>
            </title>
            <para>
			List the functions available via Kemi framework.
            </para>
            <para>
            Name: <emphasis>app_jsdt.api_list</emphasis>
            </para>
            <para>Parameters: <emphasis>none</emphasis></para>
            <para>
            Example:
            </para>
            <programlisting  format="linespecific">
...
&kamcmd; app_jsdt.api_list
...
            </programlisting>
        </section>
    </section>

    <section>
	<title>Example of usage</title>
    <para>
		Create your JS script and store it on the file system,
		say: '/usr/local/etc/kamailio/js/myscript.js'.
    </para>
<programlisting format="linespecific">
...
function sr_append_fu_to_reply()
{
	KSR.hdr.append_to_reply("P-From: " + KSR.pv.get("$fu") + "\r\n");
}
...
</programlisting>
    <para>
		Load the script via parameter 'load' and execute function
		via jsdt_run(...).
    </para>
<programlisting format="linespecific">
...
modparam("app_jsdt", "load", "/usr/local/etc/kamailio/js/myscript.js")
...
request_route {
    ...
    if(!jsdt_run("sr_append_fu_to_reply"))
    {
        xdbg("SCRIPT: failed to execute js function!\n");
    }
    ...
}
...
</programlisting>
    </section>
</chapter>

