Hướng dẫn is_readable in php

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

is_readable — Tells whether a file exists and is readable

Description

is_readable(string $filename): bool

Parameters

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

$filename = 'test.txt';
if (is_readable($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.

See Also

• is_writable() - Tells whether the filename is writable
• file_exists() - Checks whether a file or directory exists
• fgets() - Gets line from file pointer

jo at durchholz dot org ¶

16 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 ¶

6 years ago

is readable recursively. Check all sub directories and files readable
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(

pgl at yoyo dot org ¶

13 years ago

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

Anonymous ¶

17 years ago

Sometimes in situations where file_exists fails (returns false even though the file does exist) stat will work.