How should my PHP function handle invalid parameters?

Question

I'm creating some re-usable functions, and right now I have error handling setup like this:

<?php
...
public function insertAfter( $index, $objects )
{
    if ( ! is_int( $index ) ) {
        trigger_error( 'Cursor::insertAfter() expects parameter 1 to be integer, ' . gettype( $index ) . ' given', E_USER_WARNING );
    } else {
        // Do my regular code
    }

    return $this;
}
...

I tried setting it up to work just like PHP would handle an error. Is this an appropriate way to do things?

score 4 · Accepted Answer · edited May 23 '17 at 12:11

4

You may throws an exception. Take a look at Exception in PHP manual.

EDIT: Here are some useful SO threads.

edited May 23 '17 at 12:11

Community

1
1

answered Dec 09 '11 at 03:48

KV Prajapati

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I had that originally, but I prefer not to litter my code with try catch statements – Brandon Dec 09 '11 at 03:51
2

An [`InvalidArgumentException`](http://www.php.net/invalidargumentexception) would be most appropriate. – deceze Dec 09 '11 at 03:51
1

@Rogue You don't have to catch exceptions like this, that's the point. Passing an *invalid* argument type is not something that should be *caught*, it's an *exceptional mistake* that should stop your program and lead you to fix your code. – deceze Dec 09 '11 at 03:52
1

@deceze Thanks for point out [`InvalidArgumentException`](http://ca3.php.net/invalidargumentexception), this is exactly what I was looking for. Also, thank you for clarifying exceptions. – Brandon Dec 09 '11 at 03:59

score 0 · Answer 2 · edited May 23 '17 at 11:55

Check out the Altumo package. It has quite a few handy validators that do what you are looking to do.

For example,

$index = \Altumo\Validation\Numerics::assertInteger( 
    $index, 
    'Cursor::insertAfter() expects parameter 1 to be integer, ' . gettype( $index ) . ' given'
);

There are validators for Object types, strings, boolean, etc.

P.S. Exceptions are more flexible than trigger_error() because you can control them more granularly. Here's a good thread on that topic.

How should my PHP function handle invalid parameters?

2 Answers2