PHP __get overload code good practice

Question

As a good practice, should ALL my overloaded __get functions look like this example from https://www.php.net/manual/en/language.oop5.overloading.php#object.isset and include the debugging code?

public function __get($name)
{
    echo "Getting '$name'\n";
    if (array_key_exists($name, $this->data)) {
        return $this->data[$name];
    }

    /*question specific code from here on*/

    $trace = debug_backtrace();
    trigger_error(
        'Undefined property via __get(): ' . $name .
        ' in ' . $trace[0]['file'] .
        ' on line ' . $trace[0]['line'],
        E_USER_NOTICE);
    return null;
}

It seems like it could end up being a lot of duplicate code if included in every class I overload.

Have you thinked about inheritance or static helper classes? — Ricardo Souza
– Ricardo Souza, Commented Feb 24, 2012 at 1:45

J. Bruni · Accepted Answer · 2012-02-24 02:01:54Z

1

No. Your overloaded __get functions do not need to look like this example, at all.

IMHO, it is a good idea to avoid these magical functions. They seem attractive, but using this "magic" leads to hard-to-maintain code. At least, this was my experience.

One of the "principles" I "follow" today is to have "IDE-friendly" classes. I mean: if I am using Eclipse PDT, and a $variable is of a given class, the auto-complete should show to mee all methods and properties available. Using these magic methods, we can never tell what is available.

This is merely a general advice, which may not apply to your specific case.

answered Feb 24, 2012 at 2:01

J. Bruni

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Comments

simshaun · Accepted Answer · 2012-02-24 01:43:57Z

0

I would throw an exception instead of doing a debug_backtrace() and trigger_error().

It's situational though. You may wish to do something else entirely if the key doesn't exist.

answered Feb 24, 2012 at 1:43

simshaun

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zerkms · Accepted Answer · 2012-02-24 01:44:37Z

0

There is no "good practice" on such case.

Depending on the object expected behaviour (it depends on the task, nothing more) you:

Trigger notice/warning (as in your example)
Throw an exception
Return null (or some other predefined value)

answered Feb 24, 2012 at 1:44

zerkms

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rahimvirani · Accepted Answer · 2012-02-24 01:45:47Z

0

No. This example takes what would be member variables and stores them in an array member variables. You should not overload that everywhere. You should be putting this in parent classes and letting it get inherited.

Also, the output being an triggering an error is old school. Make a new exception class and throw it instead, such as PropertyNotFoundException.

answered Feb 24, 2012 at 1:45

rahimvirani

1

Comments

james_womack · Accepted Answer · 2012-02-24 01:49:40Z

0

You could wrap whatever exception handling you end up using in a global utility function which would be a bit DRYer. You can also use an AOP library to inject this functionality in your existing classes.

answered Feb 24, 2012 at 1:49

james_womack

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