app_sqlang 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)

        4. Functions

              4.1. sqlang_dofile(path)
              4.2. sqlang_dostring(script)
              4.3. sqlang_run(function [, params])
              4.4. sqlang_runstring(script)

        5. RPC Commands

              5.1. app_sqlang.reload
              5.2. app_sqlang.api_list

        6. Example of usage

   List of Examples

   1.1. Set load parameter
   1.2. sqlang_dofile usage
   1.3. sqlang_dostring usage
   1.4. sqlang_run usage
   1.5. sqlang_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)

   4. Functions

        4.1. sqlang_dofile(path)
        4.2. sqlang_dostring(script)
        4.3. sqlang_run(function [, params])
        4.4. sqlang_runstring(script)

   5. RPC Commands

        5.1. app_sqlang.reload
        5.2. app_sqlang.api_list

   6. Example of usage

1. Overview

   This module allows executing Squirrel Language (SQLang) scripts from
   config file. It exports all KEMI functions to SQLang in order to access
   the current processed SIP message. These functions are within SQLang
   object 'KSR' (a table object).

   It includes the Squirrel Language engine
   (http://www.squirrel-lang.org). Exported API from SIP router to SQLang
   is documented in the dokuwiki.

   The module has two SQLang contexts:
     * first is used for functions sqlang_dofile() and sqlang_dostring().
     * second is used for function sqlan_run() and parameter 'load'.
       Therefore sqlang_run() cannot execute functions from scripts loaded
       via sqlang_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:
     * none

3. Parameters

   3.1. load (str)

3.1. load (str)

   Set the path to the SQLang file to be loaded at startup. Then you can
   use sqlang_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_sqlang", "load", "/usr/local/etc/kamailio/sqlang/myscript.sq")
...

4. Functions

   4.1. sqlang_dofile(path)
   4.2. sqlang_dostring(script)
   4.3. sqlang_run(function [, params])
   4.4. sqlang_runstring(script)

4.1.  sqlang_dofile(path)

   Note: not implemented yet.

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

   Example 1.2. sqlang_dofile usage
...
sqlang_dofile("/usr/local/etc/kamailio/sqlang/myscript.sq");
...

4.2.  sqlang_dostring(script)

   Note: not implemented yet.

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

   Example 1.3. sqlang_dostring usage
...
if(!sqlang_dostring('KSR.dbg("test message\n")'))
{
    xdbg("SCRIPT: failed to execute squirrel script!\n");
}
...

4.3.  sqlang_run(function [, params])

   Execute the Squirrel 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 1.4. sqlang_run usage
...
if(!sqlang_run("sqlang_append_fu_to_reply"))
{
    xdbg("SCRIPT: failed to execute squirrel function!\n");
}
...
sqlang_run("sqlang_funcx", "$rU", "2");
...

4.4.  sqlang_runstring(script)

   Note: not implemented yet.

   Execute the SQLang 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 1.5. sqlang_runstring usage
...
if(!sqlang_runstring('KSR.dbg("Hello World from $fU\n")'))
{
    xdbg("failed to execute squirrel script!\n");
}
...

5. RPC Commands

   5.1. app_sqlang.reload
   5.2. app_sqlang.api_list

5.1.  app_sqlang.reload

   Marks the need to reload the SQLang script pointed by 'load' parameter.
   The actual reload is done by every working process when the next call
   to sqlang_run() function or KEMI config is executed.

   Name: app_sqlang.reload

   Parameters: none

   Example:
...
kamcmd app_sqlang.reload
...

5.2.  app_sqlang.api_list

   List the functions available via Kemi framework.

   Name: app_sqlang.api_list

   Parameters: none

   Example:
...
kamcmd app_sqlang.api_list
...

6. Example of usage

   Create your SQLang script and stored on file system, say:
   '/usr/local/etc/kamailio/sqlang/myscript.sq'.
...
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
   sqlang_run(...).
...
modparam("app_sqlang", "load", "/usr/local/etc/kamailio/sqlang/myscript.sq")
...
request_route {
    ...
    if(!sqlang_run("sr_append_fu_to_reply"))
    {
        xdbg("SCRIPT: failed to execute squirrel function!\n");
    }
    ...
}
...
