CODEWITHSUNDEEP
php
Red Virus
Red Virus

Reputation: 1707

Override a custom function value

I' am currently stuck at a point where am overriding a function value using a custom code with "call_user_func". The function name is "admin_branding" which can cater for other function to override it's default value.

Usage

<?php echo admin_branding(); ?>

From the above function, the result is "Example 1" but the outcome should be "Example 2" because am override its value using the "add_filter"

PHP Codes

/* Custom function with its custom value */
function custom_admin_branding(){
    return "Example 2";
}

/* Default function with its default value */
function admin_branding( $arg = '' ){
    if( $arg ){ $var = $arg();
    } else { $var = "Example 1"; }
    return $var;
}

/* Call User function which override the function value */
function add_filter( $hook = '', $function = '' ){
    call_user_func( $hook , "$function" );
}

/* Passing function value to override and argument as custom function */
add_filter( "admin_branding", "custom_admin_branding" );

A very example is how WordPress does using their custom add_filter function.

Upvotes: 2

Views: 413

Answers (3)

Niko
Niko

Reputation: 26730

If you want to mimic WordPress (wouldn't recommend this though):

$filters = array();

function add_filter($hook, $functionName){
    global $filters;
    if (!isset($filters[$hook])) {
        $filters[$hook] = array();
    }
    $filters[$hook][] = $functionName;
}

function apply_filters($hook, $value) {
    global $filters;
    if (isset($filters[$hook])) {
        foreach ($filters[$hook] as $function) {
            $value = call_user_func($function, $value);
        }
    }
    return $value;
}

// ----------------------------------------------------------

function custom_admin_branding($originalBranding) {
    return "Example 2";
}

function admin_branding() {
    $defaultValue = "Example 1";
    return apply_filters("admin_branding", $defaultValue); // apply filters here!
}

echo admin_branding(); // before adding the filter -> Example 1
add_filter("admin_branding", "custom_admin_branding");
echo admin_branding(); // after adding the filter -> Example 2

Upvotes: 1

Daryl Gill
Daryl Gill

Reputation: 5524

Expanding on my comment, I have drawn up a very. Very basic scenario on how I would implement such a thing:

Index.php

include "OverRides.php";
function Test(){
    return true;
}
function Call_OverRides($NameSpace, $FunctionName, $Value = array()){
    $Function_Call = call_user_func($NameSpace.'\\'.$FunctionName,$Value);
    return $Function_Call; // return the returns from your overrides

}

OverRides.php

namespace OverRides;
    function Test($Test){
        return $Test;
    }

Not actively tested, concept flows through implementation though

Debugging:

echo "<pre>";
var_dump(Test()); // Output: bool(true)
echo "<br><br>";
var_dump(Call_OverRides('OverRides','Test',"Parameter")); // Output: string(9) "Parameter"

Upvotes: 1

Etixpp
Etixpp

Reputation: 328

You may check http://php.net/manual/de/function.call-user-func.php from the PhP manual. It does not "overwrite" something, actually it just invokes your first function.

Upvotes: 1

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