To rich dot lovely at klikzltd dot co dot uk:
Using a "@" before header() to suppress its error, and relying on the "headers already sent" error seems to me a very bad idea while building any serious website.
This is *not* a clean way to prevent a file from being called directly. At least this is not a secure method, as you rely on the presence of an exception sent by the parser at runtime.
I recommend using a more common way as defining a constant or assigning a variable with any value, and checking for its presence in the included script, like:
in index.php:
<?php
define ('INDEX', true);
?>
in your included file:
<?php
if (!defined('INDEX')) {
die('You cannot call this script directly !');
}
?>
BR.
Ninj
exit
(PHP 4, PHP 5)
exit — Output a message and terminate the current script
Description
void exit
([ string
$status
] )
void exit
( int
$status
)Terminates execution of the script. Shutdown functions and object destructors will always be executed even if exit is called.
exit is a language construct and it can be called
without parentheses if no status is passed.
Parameters
-
status -
If
statusis a string, this function prints thestatusjust before exiting.If
statusis an integer, that value will be used as the exit status and not printed. Exit statuses should be in the range 0 to 254, the exit status 255 is reserved by PHP and shall not be used. The status 0 is used to terminate the program successfully.Note: PHP >= 4.2.0 does NOT print the
statusif it is an integer.
Return Values
No value is returned.
Examples
Example #1 exit example
<?php
$filename = '/path/to/data-file';
$file = fopen($filename, 'r')
or exit("unable to open file ($filename)");
?>
Example #2 exit status example
<?php
//exit program normally
exit;
exit();
exit(0);
//exit with an error code
exit(1);
exit(0376); //octal
?>
Example #3 Shutdown functions and destructors run regardless
<?php
class Foo
{
public function __destruct()
{
echo 'Destruct: ' . __METHOD__ . '()' . PHP_EOL;
}
}
function shutdown()
{
echo 'Shutdown: ' . __FUNCTION__ . '()' . PHP_EOL;
}
$foo = new Foo();
register_shutdown_function('shutdown');
exit();
echo 'This will not be output.';
?>
The above example will output:
Shutdown: shutdown() Destruct: Foo::__destruct()
Notes
Note: Because this is a language construct and not a function, it cannot be called using variable functions.
Note:
This language construct is equivalent to die().
add a note
User Contributed Notes 13 notes
void a t informance d o t info ¶
5 years ago
vincent dot laag at gmail dot com ¶
3 years ago
Don't use the exit() function in the auto prepend file with fastcgi (linux/bsd os).
It has the effect of leaving opened files with for result at least a nice "Too many open files ..." error.
dexen dot devries at gmail dot com ¶
3 years ago
If you want to avoid calling exit() in FastCGI as per the comments below, but really, positively want to exit cleanly from nested function call or include, consider doing it the Python way:
define an exception named `SystemExit', throw it instead of calling exit() and catch it in index.php with an empty handler to finish script execution cleanly.
<?php
// file: index.php
class SystemExit extends Exception {}
try {
/* code code */
}
catch (SystemExit $e) { /* do nothing */ }
// end of file: index.php
// some deeply nested function or .php file
if (SOME_EXIT_CONDITION)
throw new SystemExit(); // instead of exit()
?>
nicoladinh at gmail dot com ¶
3 years ago
Calling to exit() will flush all buffers started by ob_start() to default output.
alexyam at live dot com ¶
1 year ago
When using php-fpm, fastcgi_finish_request() should be used instead of register_shutdown_function() and exit()
For example, under nginx and php-fpm 5.3+, this will make browsers wait 10 seconds to show output:
<?php
echo "You have to wait 10 seconds to see this.<br>";
register_shutdown_function('shutdown');
exit;
function shutdown(){
sleep(10);
echo "Because exit() doesn't terminate php-fpm calls immediately.<br>";
}
?>
This doesn't:
<?php
echo "You can see this from the browser immediately.<br>";
fastcgi_finish_request();
sleep(10);
echo "You can't see this form the browser.";
?>
albert at removethis dot peschar dot net ¶
4 years ago
jbezorg at gmail proposed the following:
<?php
if($_SERVER['SCRIPT_FILENAME'] == __FILE__ )
header('Location: /');
?>
After sending the `Location:' header PHP _will_ continue parsing, and all code below the header() call will still be executed. So instead use:
<?php
if($_SERVER['SCRIPT_FILENAME'] == __FILE__)
{
header('Location: /');
exit;
}
?>
mbostrom at paragee dot com ¶
11 years ago
In PHP 4.3.1 (and possibly 4.3.0), running scripts from the command line works a lot better. This is probably because 4.3.x has a whole new CLI mode.
Specifically, exit status is now returned (to the shell) as you would expect. This is a godsend for writing embedded email processing scripts, as much email infrastructure (fetchmail, qmail, mutt, etc.) is dependant upon correctly returned status codes, and the inability to return a status code (as in PHP 4.2.x) is an insurmountable obstacle.
$_SERVER["argv"] is also always available in 4.3.x, I think, whereas in 4.2.x php.ini could prevent it from being available.
(On the downside, I had to ./configure --without-mysql in order to get 4.3.1 to compile on RedHat 8.0. Otherwise there was what looked like a fatal compile warning (that I might also have been able to ignore somehow).
The "fatal warning" FYI:
ext/mysql/libmysql/my_tempnam.o: In function `my_tempnam':
ext/mysql/libmysql/my_tempnam.c:103: the use of `tempnam' is dangerous, better use `mkstemp'
Changing the code from tempnam to mkstemp would probably not be overly complicated, but it is non-trivial.)
devinemke at devinemke dot com ¶
12 years ago
If you are using templates with numerous includes then exit() will end you script and your template will not complete (no </table>, </body>, </html> etc...). Rather than having complex nested conditional logic within your content, just create a "footer.php" file that closes all of your HTML and if you want to exit out of a script just include() the footer before you exit().
for example:
include ('header.php');
blah blah blah
if (!$mysql_connect) {
echo "unable to connect";
include ('footer.php');
exit;
}
blah blah blah
include ('footer.php');
emils at tvnet dot lv ¶
10 years ago
Note, that using exit() will explicitly cause Roxen webserver to die, if PHP is used as Roxen SAPI module. There is no known workaround for that, except not to use exit(). CGI versions of PHP are not affected.
shaun at NOshatSPAM dot net ¶
11 years ago
return may be preferable to exit in certain situations, especially when dealing with the PHP binary and the shell.
I have a script which is the recipient of a mail alias, i.e. mail sent to that alias is piped to the script instead of being delivered to a mailbox. Using exit in this script resulted in the sender of the email getting a delivery failure notice. This was not the desired behavior, I wanted to silently discard messages which did not satisfy the script's requirements.
After several hours of trying to figure out what integer value I should pass to exit() to satisfy sendmail, I tried using return instead of exit. Worked like a charm. Sendmail didn't like exit but it was perfectly happy with return. So, if you're running into trouble with exit and other system binaries, try using return instead.
matt at serverboy dot net ¶
3 years ago
It should be noted that if building a site that runs on FastCGI, calling exit will generate an error in the server's log file. This can quickly fill up.
Also, using exit will diminish the performance benefit gained on FastCGI setups. Instead, consider using code like this:
<?php
if( /* error case */ )
echo "Invalid request";
else {
/* The rest of your application */
}
?>
I've also seen developers get around this issue with FastCGI by wrapping their code in a switch statement and using breaks:
index.php:
<?php
switch(true) {
case true:
require('application.php');
}
?>
application.php:
<?php
if($x > $y) {
echo "Sorry, that didn't work.";
break;
}
// ...
?>
It does carry some overhead, but compared to the alternative, it does the job well.
jbezNULLorg at gmNULLail dot com ¶
5 years ago
If you are retroactively going through included files to prevent them from being accessed, you can use the following.
<?php
if($_SERVER['SCRIPT_FILENAME'] == __FILE__ )
header('location: /'); // or exit();
// rest of code
?>
Jorge Castro ¶
1 year ago
Another way to avoid exit is to add a conditional branch (i.e. an if).
<?php
$task=someoperation();
if (!$task) {
// for example, the task failed so we exit asap.
exit();
}
//... rest of the code...
?>
is analog to :
<?php
$task=someoperation();
if (!$task) {
// the task failed, so we do nothing and "jump" to the end of the code
//... rest of the code...
}
?>
Most of the case, to use exit is cleaner than to add a big branch.
