Smart Dialplan - use of Custom Applications

AGI in “Custom Application”

Variables in Dialplan

Variables are needed to store the information necessary to execute the application.

Syntax used to set a variable: set(variablename=value)

Where:
variablename: is the name of the variable, it is insensitive to the variables defined by users
value: is the value attributed to the variable; value can be a function.

Syntax used to call a variable:  ${variablename}

Example:

Set a variable: set(foo=123456789)

Call a variable: ${foo:offset:length}

Where:
foo: is the name of the variable
offset: optional offset in starting to read a variable
length: optional number of characters to read

${foo} → 123456789
${foO:1} → 23456789
${Foo:-4:3} → 678

Dialplan example:

• set(FOO=101) - sets the name of the variable as FOO and the value as 101
• Dial(SIP/${FOO}) - dials 101
  

Here are some useful variables:

${CALLERID(all)}: The current Caller ID name and number

${CALLERID(name)}: The current Caller ID name

${CALLERID(num)}: The current Caller ID number ${ANSWEREDTIME}: Elapsed time since the call has been answered

${EXTEN}: Extension

${CONTEXT}: Name of Dialplan procedure

${CHANNEL}: The channel (the called number present in the Dialplan procedure)

Example:

This Dialplan is assigned to user 102.
NoOp function serves to display the variable value in logs:

Conditions in Dialplan

You can use execute a conditional jump to another Dialplan procedure, based on the boolean result (true or false) of the Gotoif function.

Syntax to execute a jump: GotoIf(condition?label1:label2)

Where:

label1:label2 are the destinations of the jump, consisting of: context, extension, priority

• context: name of Dialplan procedure

• extension: extension or called number present in this Dialplan procedure

• priority: line number, usually 1

condition: the choice of Gotoif depends on the boolean result of this expression: true or false, in Dialplan True = 1 and False = 0.

The condition syntax is the following one: $[expr1 operator expr2], where

• expr can be a variable, a value, a function, an expression (expressions can be nested)

• operator as a rule it is relational (comparison) operator ( =, <>..); for nested expressions it’s possible to use logical operators AND, OR, NOT (explained below)

Logical operators:

expr1 | expr2 → OR

expr1 & expr2 → AND

!expr → NOT

Relational operators:

expr1 = expr2 → equal

expr1 != expr2 → inequal

expr1 < expr2 → less than

expr1 > expr2 → greater than

expr1 <= expr2 → less than or equal

expr1 >= expr2 → greater than or equal

Example: