[freeswitch development practice] user defined module creation and use

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What you want to say to yourself in the future

Intermittent efforts and muddle through , It's all about clearing the previous efforts

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Preface

stay FreeSwitch In the framework of , There are many modules or interfaces , stay FreeSwitch called app and api, If the commonly used answer module answer、 Hang up the module hangup、 Sleep module sleep、 Echo module echo etc. , There are a lot of them , these app and api Together FreeSwitch At the heart of . However ,FreeSwitch It also provides the function of custom module , Developers can implement one by themselves according to the standard interface app, Then use , Greatly expand FreeSwitch The ability of , It is also convenient to realize specific functions in actual business .

> Introducing `FreeSwitch` Before customizing the module , First look at a complete ` Custom module ` Example , Then introduce the custom module for the code example ：

#include <switch.h>

SWITCH_MODULE_SHUTDOWN_FUNCTION(mod_myapp_shutdown);

SWITCH_MODULE_LOAD_FUNCTION(mod_myapp_load);

// Module definition , Module loading 、 Module uninstall 
SWITCH_MODULE_DEFINITION(mod_myapp, mod_myapp_load, mod_myapp_shutdown, NULL);

SWITCH_STANDARD_APP(myapp_function);

// Module loading 
SWITCH_MODULE_LOAD_FUNCTION(mod_myapp_load)
{
    
    switch_application_interface_t *app_interface;
   
    *module_interface = switch_loadable_module_create_module_interface(pool, modname);
    
    switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "myapp mod loaded.\n");
    
    SWITCH_ADD_APP(app_interface, "myapp", "myapp", "myapp", myapp_function, "", SAF_NONE);

    return SWITCH_STATUS_SUCCESS;
}

// Module uninstall 
SWITCH_MODULE_SHUTDOWN_FUNCTION(mod_myapp_shutdown)
{
    
	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "myapp shutdown\n");
	return SWITCH_STATUS_SUCCESS;
}

//myapp  Execute function 
SWITCH_STANDARD_APP(myapp_function)
{
    
    switch_status_t status;
    
    if (session == NULL)
        return;

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "myapp function start\n");
    
	return;
}

One 、 Custom module loading and unloading

Through the code example of the above custom module , You can see that the custom module should at least be implemented 3 A standard interface ：

1. Module loading
   SWITCH_MODULE_LOAD_FUNCTION(mod_myapp_load)
2. Module uninstall
   SWITCH_MODULE_SHUTDOWN_FUNCTION(mod_myapp_shutdown)

The macro is defined as follows ：

So the complete definition of module loading and unloading is as follows ：
Module loading

switch_status_t mod_myapp_load(switch_loadable_module_interface_t **module_interface, switch_memory_pool_t *pool)

Module uninstall

switch_status_t mod_myapp_unload(void)

Two 、 Custom module "app" The creation of

Here's the key , Really usable app This interface implements ：

switch_application_interface_t *app_interface;
SWITCH_ADD_APP(app_interface, "myapp", "myapp", "myapp", myapp_function, "", SAF_NONE);

It is the same as the creation and uninstallation of modules ,app Interface is also a macro definition :

Parameter description ：

app_int	app Interface handle
int_name`	app name
short_descript	app Short description
long_descript	app Long description
funcptr	app Callback function
syntax_string	app Format string
app_flags	app sign

app Callback function

SWITCH_STANDARD_APP(myapp_function)
{
    
    switch_status_t status;
    
    if (session == NULL)
        return;

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "myapp function start\n");
    
	return;
}

As above, let's first look at the macro definition ：

#define SWITCH_STANDARD_APP(name) static void name (switch_core_session_t *session, const char *data)

Parameter description ：

session	conversation session
data	app Parameters , Every app Can pass parameters

app Callback functions can realize business specific functions , Such as ：

• Start business thread
• add to media bug, Get the call voice stream
• Realize business cycle , For example, start. ASR/TSS

3、 ... and 、 Add a custom module to the dial plan app

Add the following code to FreeSwitch Catalog conf/dialplan/default.xml

<extension name="myapp-diaplan">
  <condition field="destination_number" expression="^123$">
	<action application="answer"/>
	<action application="myapp"/>
	<action application="echo" data=""/>
	<action application="hangup" data=""/>
  </condition>
</extension>

explain ：

• destination_number Dial plan expression string , Dial now “123” number , You can do it condition Dial up configuration
• answer Answer
  -myapp This is the custom module we created earlier app
  -echo echo app, because myapp Not blocking function , So want to use echo Program to block calls , Achieve the purpose of uninterrupted call
  -hangup Hang up

Four 、 Call test

start-up FreeSwitch, Use Yate register 1000 number , First look at the custom module myapp Load output ：

Dial command ：

originate user/1000 123

123 It's the front Dial plan Configure the expression string

Output ：

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Last

That's what we have today , In detail FreeSwitch Create and use custom modules . If you feel some help or think the article is good , please Focus on What about bloggers , Your attention is the driving force of my continuous writing . in addition , If there are any questions , Leave a comment in the comments section , Or private bloggers , Bloggers will reply as soon as they see it .