How to call php function with URL? - php

Question

Hello Id like to know how to call the function I just written from URL?
Bellow are my php code.
<?php
require 'db.php';
function l1(){
echo "Hello there!";
}
function l2(){
echo "I have no Idea what Im doing!";
}
function l3(){
echo "I'm just a year 1 college student dont torture me sir!";
}
?>
I tried http://127.0.0.1/study/sf.php?function=l1 but it wont echo the written code.
Please point me to the right direction.

Answer 1

Yes you could supply that parameter into calling your user defined function:
$func = $_GET['function'];
$func();
Might as well filter the ones you have defined thru get_defined_functions
function l1(){
echo "Hello there!";
}
function l2(){
echo "I have no Idea what Im doing!";
}
function l3(){
echo "I'm just a year 1 college student dont torture me sir!";
}
$functions = $arr = get_defined_functions()['user']; // defined functions
if(!empty($_GET['function']) && in_array($_GET['function'], $functions)) {
$func = $_GET['function'];
$func();
}
Sample Output
Sidenote: function_exists can be also applied as well:
if(!empty($_GET['function']) && function_exists($_GET['function'])) {
// invoke function
}

Answer 2

One option you can do if use if/elseifs like so:
if($_GET['function'] == 'l1')
{
l1();
}
else if($_GET['function'] == 'l2')
{
l2();
}
Or you could use a riskier approach and call the function name directly from the input.
$functionName = $_GET['function'];
$functionName();
Edit:
Or you could use a switch statement:
switch($_GET['function'])
{
case 'l1':
l1();
break;
case 'l2':
l2();
break;
case 'l3':
l3();
break;
}