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

<chapter>
    
    <title>&adminguide;</title>
    
    <section>
	<title>Overview</title>
	<para>
		This module allows the execution of assemblies of managed code, among 
		the most popular of which is C# (.NET).
		It uses the Mono project (http://www.mono-project.com/) to embed the managed
		code interpreter inside the SIP server, providing fast execution.
	</para>
	<para>
		Besides C#, other languages can be used to build managed assemblies,
		such as: Java, Python, VisualBasic.NET, JavaScript. For more details on 
		what kind of languages can be used to build managed
		assemblies, see: http://www.mono-project.com/Languages
	</para>
	<para>
		A managed assembly can get access to any &kamailio; config variables
		and set them.  It can also perform many other functions implemented inside
		&kamailio; itself, allowing easier handling of SIP from managed code.
	</para>
	<para>
		There are two ways to execute managed code assemblies: load the code at
		startup and only execute at runtime, or load and execute at runtime. Only
		one mode at a time may be used.  The mode is determined by the 'load' 
		parameter and the function used to execute the code.
	</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>mono-devel</emphasis> - Mono devel toolkit.
			</para>
		    </listitem>
	    	</itemizedlist>
	    </para>
	</section>
    </section>
    <section>
	<title>Parameters</title>
	<section>
	    <title><varname>load</varname> (string)</title>
	    <para>
			Set the path to the Mono assembly to be loaded at startup.  You
			can use mono_run(param) to execute the assembly at runtime.
	    </para>
	    <para>
		<emphasis>
		    Default value is <quote>null</quote>.
		</emphasis>
	    </para>
	    <example>
		<title>Set <varname>load</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("app_mono", "load", "/usr/local/etc/kamailio/mono/myscript.exe")
...
</programlisting>
	    </example>
	</section>
	</section>
	
    <section>
	<title>Functions</title>
 	<section>
	    <title>
		<function moreinfo="none">mono_exec(path [, param])</function>
	    </title>
	    <para>
		Execute the managed code assembly stored in 'path'. The path can be
		a string with pseudo-variables evaluated at runtime. A second parameter
		can optionally be provided; it will be passed to the assembly.
	    </para>
		<para>
		Note that the assembly is loaded every time from the file, so any change
		to it is immediately live. This function cannot be used if 'load'
		parameter is set.
		</para>
		<example>
		<title><function>mono_exec</function> usage</title>
		<programlisting format="linespecific">
...
mono_exec("/usr/local/etc/kamailio/mono/myscript.exe");
...
</programlisting>
	    </example>
	</section>
	
	<section>
	    <title>
		<function moreinfo="none">mono_run([param])</function>
	    </title>
	    <para>
		Execute the assembly specified by 'load' module parameter. The assembly
		is loaded at startup, so changes to it will be effective only after &kamailio;
		restart.
	    </para>
	    <para>
			An optional parameter can be given and it will be passed over to the
			assembly. It can be a string with pseudo-variables; these will be
			evaluated at runtime.
	    </para>
		<example>
		<title><function>mono_run</function> usage</title>
		<programlisting format="linespecific">
...
if(!mono_run("myparam"))
{
    xdbg("SCRIPT: failed to execute mono assembly!\n");
}
...
</programlisting>
	    </example>
	</section>
	</section>
	
    <section>
	<title>Usage</title>
	<para>
	First, create a library from the 'SR.cs' file provided
	in the folder 'modules/app_mono/lib/'. The examples uses the folder
	/usr/local/etc/kamailio/mono/ to store the Mono-specific assemblies
	to be used by &kamailio;.
	</para>
<programlisting format="linespecific">
...
mkdir -p /usr/local/etc/kamailio/mono/
cp modules/app_mono/lib/SR.cs /usr/local/etc/kamailio/mono/
gmcs -t:library SR.cs
...
</programlisting>
	<para>
	You should see the 'SR.dll' file generated.
	</para>
    <para>
	Create your application in C#/.NET and save it
	in the same folder with SR.dll. You have to use the SR package in your
	managed source code file -- say you named MySRTest.cs. Also, be
	aware that the Main() function from the managed assembly is executed;
	thus, be sure that you have it defined.
    </para>
<programlisting format="linespecific">
...
using SR;

namespace MySRTest {
	class Test {
		static int Main(string[] args) {
			SR.Core.Log(1, "Kamailio API Version: " + SR.Core.APIVersion() + "\n");
			if (args.Length == 1) {
				SR.Core.Log(1, "Parameter from Kamailio config: "
					+ args[0] + "\n");
			}
			SR.Core.Dbg("Request URI is: " + SR.PV.GetS("$ru") + "\n");
			SR.PV.SetS("$rU", "123");
			SR.HDR.AppendToReply("My-Mono-Hdr: ok\r\n");
			SR.Core.ModF("sl_reply_error");
			return 1;
		}
	}
}
...
</programlisting>
	<para>
	You have to compile the 'SR.dll' file generated.
	</para>
<programlisting format="linespecific">
...
$ gmcs -r:SR.dll MySRTest.cs
...
</programlisting>
    <para>
		You should see the file 'MySRTest.exe' generated in the folder.
    </para>
    <para>
		In the &kamailio; config file, load the app_mono.so module and use
		its functions inside the routing blocks.
    </para>
<programlisting format="linespecific">
...
loadmodule "app_mono.so"
...
route {
    ...
    mono_exec("/usr/local/etc/kamailio/mono/MySRTest.exe");
    ...
}
...
</programlisting>
    <para>
		The API exported by the SR package to Mono applications is documented
		on the &kamailio; wiki site. Also, it is easy to figure out by looking
		in the source code tree inside the file modules/app_mono/lib/SR.cs.
    </para>
    </section>
</chapter>

