app_jsdt Module

Daniel-Constantin Mierla

   asipto.com

Edited by

Daniel-Constantin Mierla

   <miconda@gmail.com>

   Copyright © 2017 Daniel-Constantin Mierla (asipto.com)
     __________________________________________________________________

   Table of Contents

   1. Admin Guide

        1. Overview
        2. Dependencies

              2.1. Kamailio Modules
              2.2. External Libraries or Applications

        3. Parameters

              3.1. load (str)
              3.2. mode (int)

        4. Functions

              4.1. jsdt_dofile(path)
              4.2. jsdt_dostring(script)
              4.3. jsdt_run(function, params)
              4.4. jsdt_runstring(script)

        5. RPC Commands

              5.1. app_jsdt.reload
              5.2. app_jsdt.api_list

        6. Example of usage

   List of Examples

   1.1. Set load parameter
   1.2. Set mode parameter
   1.3. jsdt_dofile usage
   1.4. jsdt_dostring usage
   1.5. jsdt_run usage
   1.6. jsdt_runstring usage

Chapter 1. Admin Guide

   Table of Contents

   1. Overview
   2. Dependencies

        2.1. Kamailio Modules
        2.2. External Libraries or Applications

   3. Parameters

        3.1. load (str)
        3.2. mode (int)

   4. Functions

        4.1. jsdt_dofile(path)
        4.2. jsdt_dostring(script)
        4.3. jsdt_run(function, params)
        4.4. jsdt_runstring(script)

   5. RPC Commands

        5.1. app_jsdt.reload
        5.2. app_jsdt.api_list

   6. Example of usage

1. Overview

   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'.

   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.

   The module has two JavaScript contexts:
     * first is used for functions jsdt_dofile() and jsdt_dostring().
     * second 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.

2. Dependencies

   2.1. Kamailio Modules
   2.2. External Libraries or Applications

2.1. Kamailio Modules

   The following modules must be loaded before this module:
     * none.

2.2. External Libraries or Applications

   The following libraries or applications must be installed before
   running Kamailio with this module loaded:
     * libm - the math library (part of standard system libraries - it is
       needed to complile embedded Duktape JS interpreter).

3. Parameters

   3.1. load (str)
   3.2. mode (int)

3.1. load (str)

   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.

   Default value is “null”.

   Example 1.1. Set load parameter
...
modparam("app_jsdt", "load", "/usr/local/etc/kamailio/js/myscript.js")
...

3.2. mode (int)

   Control if the API to load JavaScript module (nodejs interface) is
   initialized or not.

   Default value is “1” (initialize).

   Example 1.2. Set mode parameter
...
modparam("app_jsdt", "mode", 0)
...

4. Functions

   4.1. jsdt_dofile(path)
   4.2. jsdt_dostring(script)
   4.3. jsdt_run(function, params)
   4.4. jsdt_runstring(script)

4.1.  jsdt_dofile(path)

   Execute the JavaScript script stored in 'path'. The parameter can be a
   string with pseudo-variables evaluated at runtime.

   Example 1.3. jsdt_dofile usage
...
jsdt_dofile("/usr/local/etc/kamailio/js/myscript.js");
...

4.2.  jsdt_dostring(script)

   Execute the JavaScript script stored in parameter. The parameter can be
   a string with pseudo-variables.

   Example 1.4. jsdt_dostring usage
...
if(!jsdt_dostring('KSR.dbg("test message\n")'))
{
    xdbg("SCRIPT: failed to execute js script!\n");
}
...

4.3.  jsdt_run(function, params)

   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.

   Example 1.5. jsdt_run usage
...
if(!jsdt_run("js_append_fu_to_reply"))
{
    xdbg("SCRIPT: failed to execute js function!\n");
}
...
jsdt_run("js_funcx", "$rU", "2");
...

4.4.  jsdt_runstring(script)

   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.

   Example 1.6. jsdt_runstring usage
...
if(!jsdt_runstring('KSR.dbg("Hello World from $fU\n")'))
{
    xdbg("failed to execute js script!\n");
}
...

5. RPC Commands

   5.1. app_jsdt.reload
   5.2. app_jsdt.api_list

5.1.  app_jsdt.reload

   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.

   Name: app_jsdt.reload

   Parameters: none

   Example:
...
kamcmd app_jsdt.reload
...

5.2.  app_jsdt.api_list

   List the functions available via Kemi framework.

   Name: app_jsdt.api_list

   Parameters: none

   Example:
...
kamcmd app_jsdt.api_list
...

6. Example of usage

   Create your JS script and store it on the file system, say:
   '/usr/local/etc/kamailio/js/myscript.js'.
...
function sr_append_fu_to_reply()
{
        KSR.hdr.append_to_reply("P-From: " + KSR.pv.get("$fu") + "\r\n");
}
...

   Load the script via parameter 'load' and execute function via
   jsdt_run(...).
...
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");
    }
    ...
}
...
