Comprehensive Guide to PHP Dynamic Method Calls: call_user_method() Function and Alternatives

Understanding the call_user_method() Function

In PHP, the call_user_method() function allows you to dynamically invoke a method on an object. Typically, we call a method directly through an object like this:

$obj->method();

However, in certain cases, you may want to call an object's method dynamically based on a variable, which can be done using call_user_method().

Using the call_user_method() Function

Syntax

call_user_method ( string $method_name , object $obj , mixed $parameter [, mixed $... ] ) : mixed

Parameter explanation:

• method_name: The name of the method to call, as a string.
• obj: The object on which to call the method.
• parameter: Parameters to pass to the method.
• ...: Multiple parameters can be passed sequentially.

Example

class MyClass {
    public function myMethod($arg1, $arg2) {
        echo "arg1=$arg1, arg2=$arg2";
    }
}
$obj = new MyClass();
call_user_method('myMethod', $obj, 'value1', 'value2'); // arg1=value1, arg2=value2

In the example above, we define the MyClass class with the myMethod() method. We then create an instance and dynamically call myMethod() using call_user_method(), passing two parameters and outputting the result.

Important Notes

• The call_user_method() function was removed in PHP 7. It is recommended to use other dynamic call methods.
• The method you want to call must exist in the target object, or errors will occur.
• You can use call_user_func() as an alternative, which supports calling object methods via an array format and is more flexible.

Example Using call_user_func() as an Alternative

class MyClass {
    public function myMethod($arg1, $arg2) {
        echo "arg1=$arg1, arg2=$arg2";
    }
}
$obj = new MyClass();
call_user_func([$obj, 'myMethod'], 'value1', 'value2'); // arg1=value1, arg2=value2

This example uses call_user_func() with an array containing the object and method name. It works similarly to call_user_method() and is compatible with PHP 7 and newer versions.

Conclusion

This article explained the usage of the call_user_method() function in PHP and its role in dynamic method invocation. Since this function was deprecated in PHP 7, developers are advised to use modern alternatives like call_user_func() to ensure compatibility and maintainability of their code.