Function Invocations

These events occur when a function is about to be executed or has finished executing.

• preFunctionInvoke - This event is triggered before a function is invoked.

• postFunctionInvoke - This event is triggered after a function has been invoked.

• onFunctionException - This event is triggered when an exception occurs during the function invocation.

preFunctionInvoke

This event is triggered before a function is invoked. It allows you to perform actions or modifications before the function execution begins.

Data Structure

Data Key	Type	Description
arguments	ArgumentsScope	The arguments scope
context	IBoxContext	The BoxLang Request context
function	Function	The UDF/Function/Closure/Lambda invoked
name	String	The name of the function invoked

Example

cass myListener{

	function preFunctionInvoke( struct data ){
		// Access the function name
		var functionName = data.name;
		
		// Log the function invocation
		log.info("Function invoked: " & functionName);
		
		// You can modify arguments if needed
		data.arguments.set("newArg", "value");
	}
}

postFunctionInvoke

This event is triggered after a function has been invoked. It allows you to perform actions or modifications after the function execution has completed.

Data Structure

Data Key	Type	Description
arguments	ArgumentsScope	The arguments scope
context	IBoxContext	The BoxLang Request context
function	Function	The UDF/Function/Closure/Lambda invoked
name	String	The name of the function invoked
result	Any	The result of the function call

Example

cass myListener{
	function postFunctionInvoke( struct data ){
		// Access the function name
		var functionName = data.name;
		
		// Log the function invocation result
		log.info("Function invoked: " & functionName & ", Result: " & data.result);
		
		// You can modify the result if needed
		data.result = "Modified Result";
	}
}

onFunctionException

This event is triggered when an exception occurs during the function invocation. It allows you to handle exceptions gracefully.

Data Structure

Data Key	Type	Description
arguments	ArgumentsScope	The arguments scope
context	IBoxContext	The BoxLang Request context
function	Function	The UDF/Function/Closure/Lambda invoked
name	String	The name of the function invoked
exception	Exception	The exception that occurred during the function invocation

Example

cass myListener{
	function onFunctionException( struct data ){
		// Access the function name
		var functionName = data.name;
		
		// Log the exception
		log.error("Exception in function: " & functionName & ", Message: " & data.exception.message);
		
		// You can handle the exception or modify the response if needed
		data.exception.message = "Custom error message";
	}
}