Question

What is the best way of creating and populating an Object from values passed in from a form?

If for example, i have a class Car with properties Colour, Model, Make, Year and a method Save, which will either insert or update the record.

I then have a form that has fields for all these values and it is submitted. I want to create an instance of class Car with the posted values and then call the Save method. All good and well.

But what is the best way of assigning the posted values to the objects internal properties. Assuming this is a simplified scenario and the actual situation would have many more properties, making individual Set calls long-winded.

Is it best to simply call the Set method for each one? Or pass in an array to a method (or the constructor) which then calls the Set methods? Or some other way?

Any advice on best practices is appreciated

Cheers
Stuart

Answer 1

I would implement the magic function __set_state(), as it is intended for exactly this use case. There are multiple benefits of putting the implementation into that method:

1. It is very well defined, what this function does (It is defined in the PHP docs, in contrast to your own source code)
2. You can access private members within the function
3. Objects dumped with var_export() will be automatically reconstructed using this function.

EDIT As requested in the comments:

class A {
    private $member = 1000;
    public static function test(A $a) {
        echo $a->member;
    }
}
echo A::test(new A()); // outputs 1000

EDIT Fulfilling another request from the comments:

You cannot know on which class a static method was called unless you are using php 5.3, in which the required feature (late static binding) was introduced. What you can do in emulating get_called_class() by analyzing the current stack (using debug_backtrace()). If you have a working get_called_class() function, you can do the following:

class BaseClass {
    public static function __set_state($state) {
        $class = get_called_class();
        // Assumption: Constructor can be invoked without parameters!
        $object = new $class();
        foreach (get_class_vars($class) as $member) {
            if (!isset($state[$member])) {
                // Member was not provided, you can choose to ignore this case
                throw new Exception("$class::$member was not provided");
            } else {
                // Set member directly
                // Assumption: members are all public or protected
                $object->$member = $state[$member];
                // Or use the setter-approach given by Chaos.
                $setter = 'set' . ucfirst($member);
                $object->setter($state[$member]);
            }
        }
        return $object;
    }
}