kamailio/misc/obsolete/cpl-c/doc/functions.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" 
   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<section id="cpl-c.functions" xmlns:xi="http://www.w3.org/2001/XInclude">
    <sectioninfo>
    </sectioninfo>

    <title>Functions</title>

    <section id="cpl_run_script">
	<title>
	    <function>cpl_run_script(type,mode)</function>
	</title>
	<para>
	    Starts the execution of the CPL script. The user name is fetched
	    from new_uri or requested uri or from To header -in this order-
	    (for incoming execution) or from FROM header (for outgoing
	    execution).  Regarding the stateful/stateless message processing,
	    the function is very flexible, being able to run in different modes
	    (see below the"mode" parameter).  Normally this function will end
	    script execution.  There is no guaranty that the CPL script
	    interpretation ended when ser script ended also (for the same
	    INVITE ;-)) - this can happen when the CPL script does a PROXY and
	    the script interpretation pause after proxying and it will be
	    resume when some reply is received (this can happen in a different
	    process of SER).  If the function returns to script, the SIP server
	    should continue with the normal behavior as if no script existed.
	    When some error is returned, the function itself haven't sent any
	    SIP error reply (this can be done from script).
	</para>
	<para>Meaning of the parameters is as follows:</para>
	<itemizedlist>
	    <listitem>
		<para>
		    <emphasis>type</emphasis> - which part of the script should
		    be run; set it to "incoming" for having the incoming part
		    of script executed (when an INVITE is received) or to
		    "outgoing" for running the outgoing part of script (when a
		    user is generating an INVITE - call).
		</para>
	    </listitem>
	    <listitem>
		<para>
		    <emphasis>mode</emphasis> - sets the interpreter mode as
		    stateless/stateful behavior. The following modes are
		    accepted:
		</para>
		<itemizedlist>
		    <listitem>
			<para>
			    <emphasis>IS_STATELESS</emphasis> - the current
				    INVITE has no transaction created yet. All
				    replies (redirection or deny) will be done
				    is a stateless way. The execution will
				    switch to stateful only when proxy is
				    done. So, if the function returns, will be
				    in stateless mode.
			</para>
		    </listitem>
		    <listitem>
			<para>
			    <emphasis>IS_STATEFUL</emphasis> - the current
				    INVITE has already a transaction
				    associated. All signaling operations
				    (replies or proxy) will be done in stateful
				    way.So, if the function returns, will be in
				    stateful mode.
			</para>
		    </listitem>
		    <listitem>
			<para>
			    <emphasis>FORCE_STATEFUL</emphasis> - the current
				    INVITE has no transaction created yet. All
				    signaling operations will be done is a
				    stateful way (on signaling, the transaction
				    will be created from within the
				    interpreter).  So, if the function returns,
				    will be in stateless mode.
			</para>
		    </listitem>
		</itemizedlist>
		<note>
		    <para>
			is_stateful is very difficult to manage from the
			routing script (script processing can continue in
			stateful mode); is_stateless is the fastest and
			consumes less resources (transaction is created only if
			proxying is done), but there is only a minimal
			protection against retransmissions (since replies are
			send statelessly); force_stateful is a good compromise
			- all signaling is done stateful (retransmission
			protection) and in the same time, if returning to
			script, it will be in stateless mode (easy to continue
			the routing script execution)
		    </para>
		</note>
	    </listitem>
	</itemizedlist>
	<example>
	    <title><function>cpl_run_script</function> usage</title>
	    <programlisting>
...
cpl_run_script("incoming","force_stateful");
...
	    </programlisting>
	</example>
    </section>

    <section id="cpl_process_register">
	<title>
	    <function moreinfo="none">cpl_process_register()</function>
	</title>
	<para>
	    This function MUST be called only for REGISTER requests. It checks
	    if the current REGISTER request is related or not with CPL script
	    upload/download/ remove. If it is, all the needed operation will be
	    done. For checking if the REGISTER is CPL related, the function
	    looks fist to "Content-Type" header. If it exists and has a the
	    mime type set to "application/cpl+xml" means this is a CPL script
	    upload/remove operation. The distinction between to case is made by
	    looking at "Content-Disposition" header; id its value is
	    "script;action=store", means it's an upload; if it's
	    "script;action=remove", means it's a remove operation; other values
	    are considered to be errors. If no "Content-Type" header is
	    present, the function looks to "Accept" header and if it contains
	    the "*" or "application/cpl-xml" the request it will be consider
	    one for downloading CPL scripts.  The functions returns to script
	    only if the REGISTER is not related to CPL. In other case, the
	    function will send by itself the necessary replies (stateless -
	    using sl), including for errors.
	</para>
    </section>

</section>