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

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


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.