Alex Rivera | Logout

Are exceptions in php really that useful?

Asked 2010-08-23T15:58:48.547
11

3 days ago I started rewriting one of my scripts in OOP using classes as a practice after reading a lot about the advantages of using OOP.

Now I'm confused weather I should use exceptions or not. They seem to make my work harder and longer.

My application check if the data was sent through an Ajax request or not then uses that info through the script.

Check this example : 

 /*
 * The older way
 */

if($ajaxEnabled) {
    $error = errorWrap('Ajax error');
} else {
    $error = errorWithBackLinkWrap('NoAjax error');
}

function doSomething() {
    if(empty($POST['name'])) {
            die($error);
    }
}

/* 
 * OOP way
 */

class someClass {
    private $_ajaxEnabled;

    public function doSomething() {
        try {
            if(!$this->_isDateValid()) {
                if($this->$_ajaxEnabled) {
                    throw new ajaxException('Ajax error');
                } else {
                    throw new noAjaxException('NOAjaxError');
                }
            }
        } catch(ajaxException $e) {
            echo $e->getErrorMessage();
        } catch(noAjaxException $e) {
            echo $e->getErrorMessage();
        }
    }
}

This code is only for demonstrating the problem, so I know there are some undefined functions in it :).

So before going oop, error handling was easier for me because I only had to echo the appropriate error.

Now using exceptions, in every function I have to check the type of connection first then write 2 catch functions for each thrown exception, which lead to a much larger code.

I'm really new to OOP in php so maybe there is a cleaner and a better way to do this, is there ?

php oop exception
Edit
Report

2 Answers

1

I personally hate exceptions. I don't work with them in my applications. I prefer functions returning (and expecting) defined status codes, and dealing with recoverable errors on that level.

In truly exceptional situations (like an unreachable database server, a file I/O error etc.) that are an immediate emergency, I tend to trigger and handle a fatal error. (Object shutdown will still take place, so any connections that need closing etc. will still be handled as long as they are placed in destructor functions.)

Third party libraries' exceptions I strive to catch as quickly as possible, and deal with them in my own way.

Joel Spolsky puts the reasons much better than I could in his notorious Exceptions essay.

Note that this is one view and one school of thought. There is a lot of brilliant software whose error handling is based entirely on exceptions, and that is perfectly fine. The key is consistence - either you make the design decision to use them, or you don't.

answered 2010-08-23T16:08:32.050
1

There is a finite capacity to most development processes - i.e. even where its possible to predict all possible circumstances that the code might run in (i.e. all possible combinations of inputs, all possible states for supporting systems like database, DNS, existing data etc) then its just not practical to deal with every scenario. Using exceptions allows you:

  1. to bundle a series of operations into one entity for the purposes of determining success/ failure as a whole

  2. handle multiple different modes of failures with a single bit of code

So yes - I'd say that exception handling is a useful practice - but not a substitute for handling the common failure modes specifically, intelligently and informatively (and typed exceptions are IMHO a complete oxymoron).

answered 2010-08-23T16:29:29.847

Your Answer