In PHP v 5.6 how do I catch UnexpectedValueException?

Question

I've reviewed a number of ways to determine that a directory is empty or not, and many indicate that $isDirEmpty = !(new \FilesystemIterator($dir))->valid(); is a good choice, except that the directory path in the $dir parameter must exist or else an UnexpectedValueException is thrown. Please see How can I use PHP to check if a directory is empty? for more details about using this method.

However, this and other examples first need to use other functions/statements to determine if the directory exists before using FileSystemIterator to retrieve the iterator and test its item, but these often cache information about the directory and that needs to be explicitly released after they are used, which many of these examples do not do.

To get around these extra 'details' and aid in my debugging, I've decided to implement the FileSystemIterator technique in a function that uses a try/catch block and instead of the valid method that returns true if the file system item is valid (whatever that means) or false, I'm using the getPathname method so I can see the actual directory/file's path name when I debug the code.

Here is my function, but I need the catch() parameter to finish it:

function isDirectoryEmpty( $dir ) {

    //
    // Create a file system iterator from the directory path and get the first
    // directory content item, if one exists,  Note, FilesystemIterator ignores
    // the special . and .. entries in a directory that always exist, so I don't
    // need to filter them out with code.

    try {

        $iterator = new \FilesystemIterator( $dir );

        foreach( $iterator as $fileinfo ) {

            $filePathName = $fileinfo->getPathname();
            break;

        }

    }
    catch( WHAT_GOES_HERE ) {

        $filePathName = '';

    }

    return  ( $filePathName === '' );

}

Since I only need one existing directory member to prove is the directory isn't empty, I break out of the foreach block that fetches the file information from the iterator, but it would be cleaner if I knew how to do this without the foreach loop statement. Would someone also give me the code that does this.

UPDATE

The foreach loop can be replaced as follows:

$filePathName = ''; // Assume that the $dir directory is empty, even if it
                    // doesn't exist and the FilesystemIterator creation
                    // method throws an exception.

try {

    $filePathName = ( new \FilesystemIterator( $dir ) )->getPathname();

}
catch( UnexpectedValueException $exception ) {} // Other than catching the
                                                // exception, no other action
                                                // is needed.

Thanks.

score 1 · Accepted Answer · answered Jul 16 '20 at 23:09

1

If the exception that you are getting is UnexpectedValueException, you can catch it specifying its type in the catch statement like this:

try {
     // some logic
} catch( UnexpectedValueException $exception) {
    // Print the exception message
    echo 'Message: ' .$exception->getMessage(); 
}

answered Jul 16 '20 at 23:09

Martin Pacheco

91
7

Thanks, I updated my function as you suggested and I added code to replace the foreach block. – Jul 17 '20 at 01:47

In PHP v 5.6 how do I catch UnexpectedValueException?

1 Answers1