freeswitch/libs/freetdm/docs/variables.txt

1. User application sending variables or raw buffer to FreeTDM
==============================================================

The User can attach a ftdm_sigmsg_t to ftdm_caller_data_t before sending an event to freetdm.

example #1 - Adding a variable:
-------------------------------

When using ftmod_sangoma_isdn, user want to specify progress indicator inside PROCEED message.


	ftdm_caller_data_t *caller_data;
	ftdm_sigmsg_t sigmsg;

	/* Attach variable to sigmsg */
	ftdm_event_add_var(&sigmsg, "isdn.prog_ind.descr", "inband-info-available");
	
	
	/* Attach sigmsg to channel's caller_data */
	caller_data = ftdm_channel_get_caller_data(ftdmchan);
	caller_data->sigmsg = &sigmsg;

	/* Request FreeTDM to send a PROCEED msg */
	ftdm_channel_call_indicate(ftdmchan, FTDM_CHANNEL_INDICATE_PROCEED);

Note: 
1.When ftdm_channel_call_indicate returns, caller_data->sigmsg will be NULL. 



example #2a - Setting raw data without autofree feature:
--------------------------------------------------------

When using ftmod_sangoma_isdn, user wants to transmit a custom Facility IE, inside a FACILITY message.
	
	ftdm_caller_data_t *caller_data;
	ftdm_sigmsg_t sigmsg;
	uint8_t my_facility_ie [200];
	unsigned my_facility_ie_len = 0;

	/* Fill my_facility_ie with custom data here */
	my_facility_ie[my_facility_ie_len++] = 0x1C; /* Q.931 Facility IE ID */
	my_facility_ie[my_facility_ie_len++] = 0x03; /* Length of facility IE */
	my_facility_ie[my_facility_ie_len++] = 0x01;
	my_facility_ie[my_facility_ie_len++] = 0x02;
	my_facility_ie[my_facility_ie_len++] = 0x03;
	

	sigmsg.raw.data = my_facility_ie;
	sigmsg.raw.len = my_facility_ie_len;
	sigmsg.raw.autofree = 0;

	/* Attach sigmsg to channel's caller_data */
	caller_data = ftdm_channel_get_caller_data(ftdmchan);
	caller_data->sigmsg = &sigmsg;

	sigmsg.event_id = FTDM_SIGEVENT_FACILITY;

	ftdm_channel_call_send_msg(ftdmchan, sigmsg);



example #2b - Setting raw data with autofree feature:
-----------------------------------------------------

	ftdm_caller_data_t *caller_data;
	ftdm_sigmsg_t sigmsg;
	uint8_t *my_facility_ie = ftdm_calloc(1, 200);
	unsigned my_facility_ie_len = 0;

	/* Fill my_facility_ie with custom data here */
	my_facility_ie[my_facility_ie_len++] = 0x1C; /* Q.931 Facility IE ID */
	my_facility_ie[my_facility_ie_len++] = 0x03; /* Length of facility IE */
	my_facility_ie[my_facility_ie_len++] = 0x01;
	my_facility_ie[my_facility_ie_len++] = 0x02;
	my_facility_ie[my_facility_ie_len++] = 0x03;
	

	sigmsg.raw.data = my_facility_ie;
	sigmsg.raw.len = my_facility_ie_len;
	sigmsg.raw.autofree = 1;

	/* Attach sigmsg to channel's caller_data */
	caller_data = ftdm_channel_get_caller_data(ftdmchan);
	caller_data->sigmsg = &sigmsg;

	sigmsg.event_id = FTDM_SIGEVENT_FACILITY;

	ftdm_channel_call_send_msg(ftdmchan, sigmsg);

	/* FreeTDM will automatically free my_facility_ie */


2. User application receiving variables and raw buffer from FreeTDM
==================================================================

example #1 - print all variables received from FreeTDM
------------------------------------------------------

	/* Inside event call-back function */
	ftdm_iterator_t *iter = NULL;
	ftdm_iterator_t *curr = NULL;
	const char *var_name = NULL;
	const char *var_value = NULL;

	/* Read all variables attached to this event */
	iter = ftdm_event_get_var_iterator(sigmsg, iter);
	for (curr = iter ; curr; curr = ftdm_iterator_next(curr)) {
		ftdm_get_current_var(curr, &var_name, &var_value);
		fprintf("Call Variable: %s=%s\n", var_name, var_value);
	}
	ftdm_iterator_free(iter);	


example #2 - accessing a specific variable
------------------------------------------

	/* Inside event call-back function */
	char *string = NULL;
	string = ftdm_event_get_var(sigmsg, "isdn.prog_ind.descr");
	if (string && *string) {
		fprintf("Progress indicator:%s\n", string);
	}


example #3 - accessing raw data
-------------------------------

	/* Inside event call-back function */
	ftdm_size_t len;
	uint8_t *mydata;
	if (ftdm_event_get_raw_data(sigmsg, (void**)&mydata, &len) == FTDM_SUCCESS) {
		/* raw data is available, do something with mydata here */
	}