is_link
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.
is_readable
(PHP 4, PHP 5)
is_readable — Tells whether a file exists and is readable
Opis
bool is_readable
( string
$filename
)Tells whether a file exists and is readable.
Parametry
-
filename -
Path to the file.
Zwracane wartości
Returns TRUE if the file or directory specified by
filename exists and is readable, FALSE otherwise.
Przykłady
Przykład #1 is_readable() example
<?php
$filename = 'test.txt';
if (is_readable($filename)) {
echo 'The file is readable';
} else {
echo 'The file is not readable';
}
?>
Błędy/Wyjątki
W przypadku niepowodzenia jest emitowany E_WARNING.
Notatki
Keep in mind that PHP may be accessing the file as the user id that the web server runs as (often 'nobody'). Safe mode limitations are not taken into account before PHP 5.1.5.
Informacja: Wyniki działania tej funkcji są buforowane. Zobacz opis funkcji clearstatcache() aby uzyskać więcej informacji.
Wskazówka
Od PHP 5.0.0 ta funkcja może być użyta także z niektórymi nakładkami URL. Zobacz Supported Protocols and Wrappers aby uzyskać listę nakładek, które obsługują funkcjonalność z rodziny stat().
Informacja:
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.
Zobacz też:
- is_writable() - Tells whether the filename is writable
- file_exists() - Sprawdza czy plik lub katalog istnieje
- fgets() - Pobiera linię ze wskaźnika pliku
add a note
User Contributed Notes
is_readable - [5 notes]
jo at durchholz dot org ¶
7 years ago
pgl at yoyo dot org ¶
3 years ago
Note that is_readable() will return false for streams, eg, php://stdin.
DrTebi at yahoo dot com ¶
7 years ago
Be careful when using is_readable on symbolic links.
is_readable will return true if the file the symbolic link is pointing to is readable.
The problem is that if the server does NOT allow to follow symbolic links, is_readable will still return true, but e.g. redirecting to the sybolic link will not work. For Apache, make sure that at the server, virtual host configuration level, or inside a directory container you have set
Options +FollowSymLinks
As an example, let's say you have at the document root directory:
index.php -- the script using is_readable
my_linked_page.html -- a regular HTML page
my_link -- a link pointing to my_linked_page.html
Now in index.php:
<?php
if (is_readable('my_link')) {
header('Location: /my_link');
}
?>
If FollowSymLinks is forbidden, this will not work, if allowed, it will.
Anonymous ¶
7 years ago
Sometimes in situations where file_exists fails (returns false even though the file does exist) stat will work.
jascha át gmx dót com ¶
6 years ago
Safe_mode restrictions ignored means:
cant read by read() so is_readable() = false.
even if safe_mode_include_dir is set and include does works, is_readable() is false to. :(
(php5)