app_sqlang Module

Daniel-Constantin Mierla

asipto.com

Edited by

Daniel-Constantin Mierla


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_swlang.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

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

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)

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 requited 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)

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_swlang.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");
    }
    ...
}
...