PHP: is_readable - Manual

(PHP 4, PHP 5, PHP 7, PHP 8)

is_readable — Tells whether a file exists and is readable

Description

function is_readable(string $filename): bool

Parameters

filename: Path to the file.

Return Values

Returns true if the file or directory specified by filename exists and is readable, false otherwise.

Errors/Exceptions

Upon failure, an E_WARNING is emitted.

Examples

Example #1 is_readable() example

<?php
$filename = 'test.txt';
if (is_readable($filename)) {
    echo 'The file is readable';
} else {
    echo 'The file is not readable';
}
?>

Notes

Keep in mind that PHP may be accessing the file as the user id that the web server runs as (often 'nobody').

Note: The results of this function are cached. See clearstatcache() for more details.

Note:
The check is done using the real UID/GID instead of the effective one.

This function may return true for directories. Use is_dir() to distinguish file and directory.

Found A Problem?

jo at durchholz dot org ¶

20 years ago

DrTebi at yahoo dot com is wrong. is_readable() checks whether you can do file_get_contents() or similar calls, no more, no less. If the location given returns a 500 or 403 error, you can still read() that (you'll simply get the error page), but it's still read()able. Using is_readable to check the validity of a URL is simply the wrong function.

arikan134 at gmail dot com ¶

10 years ago

is readable recursively. Check all sub directories and files readable
<?php
function is_readable_r($dir) {
    if (is_dir($dir)) {
        if(is_readable($dir)){
            $objects = scandir($dir);
            foreach ($objects as $object) {
                if ($object != "." && $object != "..") {
                    if (!is_readable_r($dir."/".$object)) return false;
                    else continue;
                }
            }    
            return true;    
        }else{
            return false;
        }
        
    }else if(file_exists($dir)){
        return (is_readable($dir));
        
    }
}

?>

pgl at yoyo dot org ¶

16 years ago

Note that is_readable() will return false for streams, eg, php://stdin.

anrdaemon at yandex dot ru ¶

1 month ago

Do note that is_readable/is_writable evaluates permissions in an attempt to produce the result.

This WILL fail in certain situations, while the file is actually accessible to the user, but manual evaluation fails to connect the dots.

The only trusted way to detect if a file is readable is to actually open it for reading. The only trusted way to detect if a file is writable is to actually open it for writing. And catche the error in case of failure.

johninen at gmail dot com ¶

1 year ago

This will return false on urls, even if file_get_contents() reads them. So, only for files.