Calling a specific function from PHP with Jquery & Ajax - php

Question

For me this is something new, so I am just researching this and trying to understand it.
As you can see in the php script there are 2 functions and I am trying to call a specific one with jquery.
Now if I have one function then I can do it, but when I have 2 or more I am starting to get stuck.
I suppose I could do this when I have 2 functions, but as soon as more variables are in play or more functions do I just make massive if statements in my php?
The problem is that when I attach a database to it, I would need to consider all inputs that can happen.
How do I specify a specific php function when using jquery & ajax?
//function.php
<?php
function firstFunction($name)
{
echo "Hello - this is the first function";
}
function secondFunction($name)
{
echo "Now I am calling the second function";
}
?>
<?php
$var = $_POST['name'];
if(isset($var))
{
$getData = firstFunction($var);
}
else if(isset($var))
{
$getData = secondFunction($var);
}
else
{
echo "No Result";
}
?>
//index.html
<div id="calling">This text is going to change></div>
<script>
$(document).ready(function() {
$('#calling').load(function() {
$.ajax({
cache: false,
type: "POST",
url: "function.php",
data: 'name=myname'
success: function(msg)
{
$('#calling').html((msg));
}
}); // Ajax Call
}); //event handler
}); //document.ready
</script>

Answer 1

You need to pass a parameter in, either via the data object or via a GET variable on the URL. Either:
url: "function.php?action=functionname"
or:
data: {
name: 'myname',
action: 'functionname'
}
Then in PHP, you can access that attribute and handle it:
if(isset($_POST['action']) && function_exists($_POST['action'])) {
$action = $_POST['action'];
$var = isset($_POST['name']) ? $_POST['name'] : null;
$getData = $action($var);
// do whatever with the result
}
Note: a better idea for security reasons would be to whitelist the available functions that can be called, e.g.:
switch($action) {
case 'functionOne':
case 'functionTwo':
case 'thirdOKFunction':
break;
default:
die('Access denied for this function!');
}
Implementation example:
// PHP:
function foo($arg1) {
return $arg1 . '123';
}
// ...
echo $action($var);
// jQuery:
data: {
name: 'bar',
action: 'foo'
},
success: function(res) {
console.log(res); // bar123
}

Answer 2

You are actually quite close to what you want to achieve.
If you want to specify which function will be called in PHP, you can pass a variable to tell PHP. For example, you passed request=save in AJAX, you can write the PHP as follow:
$request = '';
switch(trim($_POST['request'])) {
case 'save':
$player_name = (isset($_POST['playername']) ? trim($_POST['player_name']) : 'No Name'));
saveFunction($player_name);
break;
case 'load':
loadFunction();
break;
default:
// unknown / missing request
}
EDIT: You can even pass along with other parameters

Answer 3

This may not be exactly what you are looking for but it can help some others looking for a very simple solution.
In your jquery declare a variable and send it
var count_id = "count";
data:
{
count_id: count_id
},
Then in your php check if this variable is set
if(isset($_POST['count_id'])) {
Your function here
}