signaling Module

Anca-Maria Vamanu

Edited by

Anca-Maria Vamanu

   Copyright © 2008 FhG FOKUS
   Revision History
   Revision $Revision: 5901 $ $Date$
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   Table of Contents

   1. Admin Guide

        1.1. Overview
        1.2. Dependencies

              1.2.1. OpenSIPS Modules
              1.2.2. External Libraries or Applications

        1.3. Exported Parameters
        1.4. Exported Functions

              1.4.1. send_reply(code, reason)

   List of Examples

   1.1. sl_send_reply usage

Chapter 1. Admin Guide

1.1. Overview

   The SIGNALING module comes as a wrapper over tm and sl modules
   and offers one function to be called by the modules that want
   to send a reply.

   The logic behind the module is to first search if a transaction
   is created and if so, send a state full reply, using tm module,
   otherwise send a stateless reply with the function exported by
   sl. In this way, the script writer still has the call on how
   the transaction should be handled, state full or stateless and
   the reply is send accordingly to his choice.

   For example, if you do a t_newtran() in the script before doing
   save() (for registration), the function will automatically send
   the reply in stateful mode as a transaction is available. If no
   transaction is done, the reply will be sent in stateless way
   (as now).

   By doing this, we have the possibility to have same module
   sending either stateful either stateless replies, by just
   controlling this from the script (if we create or not a
   transaction). So, the signalling will be more coherent as the
   replies will be sent according to the transaction presence (or
   not).

   Moreover, this module offers the possibility of loading only
   one of the module, sl or tm, and send reply using only the
   module that is loaded. This is useful as not in all cases a
   user desires to send stateful or stateless replies and he
   should not be forced to load the module only because the send
   reply interface requires it.

1.2. Dependencies

1.2.1. OpenSIPS Modules

   At least one of the following modules must be loaded before
   this module:
     * sl.
     * tm.

1.2.2. External Libraries or Applications

   The following libraries or applications must be installed
   before running OpenSIPS with this module loaded:
     * None.

1.3. Exported Parameters

     * None.

1.4. Exported Functions

1.4.1.  send_reply(code, reason)

   For the current request, a reply is sent back having the given
   code and text reason. The reply is sent stateless or statefull
   depending on which module is loaded and if a transaction was
   created, as explained above.

   Meaning of the parameters is as follows:
     * code - Return code.
     * reason - Reason phrase.

   This function can be used from REQUEST_ROUTE, ERROR_ROUTE.

   Example 1.1. sl_send_reply usage
...
send_reply("404", "Not found");
...
send_reply("$err.rcode", "$err.rreason");
...
