Call different PHP functions from javascript

Question

I realize that calling database from JavaScript file is not a good way. So I have two files:

client.js
server.php

server.php has multiple functions. Depending upon a condition, I want to call different functions of server.php. I know how to call server.php, but how do I call different functions in that file?

My current code looks like this:

 function getphp () {
     //document.write("test");
     xmlhttp = new XMLHttpRequest();
     xmlhttp.onreadystatechange = function() {
        if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
            // data is received. Do whatever.
        }
     }
     xmlhttp.open("GET","server.php?",true);
     xmlhttp.send();
 };

What I want to do is something like (just pseudo-code. I need actual syntax):

xmlhttp.open("GET","server.php?functionA?params",true);

Just use a [micro-framework](http://silex.sensiolabs.org/) or a [full flegdeg one](http://symfony.com/)… — nietonfir, Oct 03 '14 at 07:26
@Cerbrus: I believe this is not a duplicate. The link you suggested tell me how to call one particular php file. I am looking to find how to call multiple functions all in one php file. — Manas Paldhe, Oct 03 '14 at 07:33

score 5 · Accepted Answer · answered Oct 03 '14 at 07:24

5

Well based on that premise you could devise something like this:

On a sample request like this:

xmlhttp.open("GET","server.php?action=save",true);

Then in PHP:

if(isset($_GET['action'])) {
    $action = $_GET['action'];

    switch($action) {
        case 'save':
            saveSomething();
        break;
        case 'get':
            getSomething();
        break;

        default:
            // i do not know what that request is, throw an exception, can also be
        break;
    }
}

answered Oct 03 '14 at 07:24

Kevin

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Add a `default` case to the `switch` statement, which throws an exception, for easy debugging. – Mysteryos Oct 03 '14 at 07:27
So there is no built-in way to do this? – Manas Paldhe Oct 03 '14 at 07:36
This _is_ the built-in way. – Cerbrus Oct 03 '14 at 07:36
@ManasPaldhe what does that mean? `built-in` way? so you want a function that does this all? no i don't think there is no function that does it all. – Kevin Oct 03 '14 at 07:38
@Ghost: Yes, that is what I meant. That is fine. I will use the above answer! :) – Manas Paldhe Oct 03 '14 at 08:07
@ManasPaldhe There's no such thing as a `built-in` way, but I guess you want to use a dynamic way of calling functions and you want to avoid using a `switch` loop and static values. I posted a solution for this problem. – Wissam El-Kik Oct 03 '14 at 08:26

score 1 · Answer 2 · edited Oct 03 '14 at 07:24

1

Just do something like this, i hope this will work

xmlhttp.open("GET","server.php?function=functioName&paramsA=val1&param2=val2",true);

edited Oct 03 '14 at 07:24

Zaheer Ahmed

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answered Oct 03 '14 at 07:22

Ekansh Rastogi

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score 1 · Answer 3 · answered Oct 03 '14 at 07:26

You will most likely need to create the mechanism yourself.

Say the URL will look like server.php?function=foo&param=value1&param=value2

On the server side you will now have to check whether a function with such a name exists, and if it does, call it with these parameters. Useful links on how to do it are http://php.net/manual/en/function.function-exists.php and http://php.net/manual/en/functions.variable-functions.php

Otherwise, if you don't want to have it like this, you can always go with if/switch and simply check that if $_GET["function"] is something, then call something etc.

score 1 · Answer 4 · answered Oct 03 '14 at 07:59

You can use jQuery too. Much less code than pure js. I know pure js is faster but jQuery is simpler. In jQuery you can use the $.ajax() to send your request. It takes a json structured array like this:

$.ajax({
    url: "example.php",
    type: "POST",
    data: some_var,
    success: do_stuff_if_no_error_occurs(),
    error: do_stuff_when_error_occurs()
});

score 1 · Answer 5 · answered Oct 03 '14 at 08:24

Here's a dynamic way to solve this issue:

xmlhttp.open("GET","server.php?action=save",true);

PHP Code:

<?php
$action = isset($_GET['action']) ? $_GET['action'] : ''; 
if(!empty($action)){
    // Check if it's a function
    if(function_exists($action)){
        // Get all the other $_GET parameters
        $params = array();
        if(isset($_GET) && sizeof($_GET) > 1){
            foreach($_GET as $key => $value){
                if($key != 'action'){
                    $params[] = $value;
                }
            }
        }
        call_user_func($action, $params);
    }
}
?>

Keep in mind that you should send the parameters in the same order of function arguments. Let's say:

xmlhttp.open("GET","server.php?action=save&username=test&password=mypass&product_id=12",true);

<?php
function save($username, $password, $product_id){
   ...
}
?>

You can't write the API Call that way:

xmlhttp.open("GET","server.php?action=save&password=mypass&username=test&product_id=12",true);

Keep in mind that it's really bad to send "function namespaces" along with the parameters to a back-end. You're exposing your back-end and without proper security measures, your website will be vulnerable against SQL Injection, dictionary attack, brute force attack (because you're not checking a hash or something), and it'll be accessible by almost anyone (you're using GET using of POST and anyone can do a dictionary attack to try to access several functions ... there's no privileges check) etc.

My recommendation is that you should use a stable PHP Framework like Yii Framework, or anything else. Also avoid using GET when you're sending data to the back-end. Use POST instead.

Call different PHP functions from javascript

5 Answers5