Make set_time_limit() timeout a catchable fatal error View as Markdown

I'm personally a fan of errors and well defined return values. Exceptions
doesn't solve any problem unless your problem is that your code is not
enough spaghetti-ish. But I agree with "All fatal errors should be changed
to catchable fatal errors".

~Hannes

Fatal error are most dumb feature in the language.
The are lot of "blind" areas where you don't know if you will ever
return...

include "file.php";
new Class();
call_func();

All fatal errors should be changed to "catchable fatal errors" so
applications will be able to recover themselves... and if they don't catch
the error... then die.

it would be nice if all errors could be changed into exceptions.

Martin Scotta

On Wed, Mar 9, 2011 at 10:56 AM, Hannes Landeholm landeholm@gmail.comwrote:

I second making time limit reached catchable. All non catchable fatal
errors
are a problem for me. I need to handle problems gracefully to ensure the
stability of production systems instead of PHP just killing itself without
warning. I just reported a similar issue:
http://bugs.php.net/bug.php?id=54195

A simple way to implement this would be to register a function that would
be
called N seconds before the script would timeout.

register_timeout_handler(2, function() { die("PHP timed out."); });

It would be called just as a shutdown function - in fact I'd like to use
the
same function as my shutdown function and get the error with
error_get_last(). Of course set_time_limit(0) could be used in this
function
to prevent the timeout of the timeout handler. This does not "prevent"
timeout since set_time_limit could have been called by the script before
the
timeout anyway.

On that note I also miss a function which returns the time the script can
keep running for. If that calculate needs to be calculated to implemented
to
implement this, why not make the value available to the PHP script?

~Hannes

Although it doesn't let you recover from a timeout, you could use
register_shutdown_function to gracefully exit after a fatal error.

register_shutdown_function(function(){
$error = error_get_last();
if($error && $error['type'] === E_ERROR){
echo 'PHAIL! Oh noes, something went wrong!';
// do whatever else you need to do before quitting
}
});

Cheers,
David

hi,

is not the goal of this setting to prevent that a script runs longer
than a given time? A catchable error will prevent that to happen.

On Tue, Mar 8, 2011 at 2:05 PM, Sebastian Bergmann <sebastian@php.net

wrote:

Could set_time_limit() be changed in such a way that it triggers a
catchable fatal error instead of a fatal error? Thanks!

--
Sebastian Bergmann Co-Founder and Principal
Consultant
http://sebastian-bergmann.de/
http://thePHP.cc/

You mean the shutdown function is called and 1 nanosecond later PHP crashes
so you don't have time to do anything?

~Hannes

Hmm, I think I worded that poorly.
A function registered with register_shutdown_function does execute when
the max_execution_time is exceeded.
What it doesn't let you do is to recover in the same way an error
handler would let you.

David

I second making time limit reached catchable. All non catchable fatal
errors
are a problem for me. I need to handle problems gracefully to ensure the
stability of production systems instead of PHP just killing itself
without
warning. I just reported a similar issue:
http://bugs.php.net/bug.php?id=54195

A simple way to implement this would be to register a function that would
be
called N seconds before the script would timeout.

register_timeout_handler(2, function() { die("PHP timed out."); });

It would be called just as a shutdown function - in fact I'd like to use
the
same function as my shutdown function and get the error with
error_get_last(). Of course set_time_limit(0) could be used in this
function
to prevent the timeout of the timeout handler. This does not "prevent"
timeout since set_time_limit could have been called by the script before
the
timeout anyway.

On that note I also miss a function which returns the time the script can
keep running for. If that calculate needs to be calculated to implemented
to
implement this, why not make the value available to the PHP script?

~Hannes

Although it doesn't let you recover from a timeout, you could use
register_shutdown_function to gracefully exit after a fatal error.

register_shutdown_function(function(){
$error = error_get_last();
if($error && $error['type'] === E_ERROR){
echo 'PHAIL! Oh noes, something went wrong!';
// do whatever else you need to do before quitting
}
});

Cheers,
David

hi,

is not the goal of this setting to prevent that a script runs longer
than a given time? A catchable error will prevent that to happen.

On Tue, Mar 8, 2011 at 2:05 PM, Sebastian Bergmann sebastian@php.net
wrote:

Could set_time_limit() be changed in such a way that it triggers a
catchable fatal error instead of a fatal error? Thanks!

--
Sebastian Bergmann Co-Founder and Principal
Consultant
http://sebastian-bergmann.de/
http://thePHP.cc/

Yes, it's possible to measure the "time left" yourself. However
set_time_limit documentation states that not all time are accounted for when
measuring how long the script can run for. If it's a UNIX system and you're
using system operations/database queries etc there will be a difference
between the time you measure the script has run for and the time PHP has
measured.

And this is only a suitable solution in controlled code like when you're
doing something defined in a loop and can measure the time with regular
intervals. I need it for my framework which can contain any kind of logic,
even logic that uses set_time_limit by itself.

~Hannes

A simple way to implement this would be to register a function that would
be
called N seconds before the script would timeout.

register_timeout_handler(2, function() { die("PHP timed out."); });

It would be called just as a shutdown function - in fact I'd like to use
the
same function as my shutdown function and get the error with
error_get_last(). Of course set_time_limit(0) could be used in this
function
to prevent the timeout of the timeout handler. This does not "prevent"
timeout since set_time_limit could have been called by the script before
the
timeout anyway.

I like this. Although, I'd rather the first parameter were in milliseconds
instead of seconds. This would tell PHP 'x' milliseconds before script
termination to call the specified function. That function would then have
the remainder of the time slice to execute cleanup routines and send any
errors to the user. This approach also doesn't require a whole new
configuration option in php.ini.

On that note I also miss a function which returns the time the script can

keep running for. If that calculate needs to be calculated to implemented
to
implement this, why not make the value available to the PHP script?

This is already possible to do. I do this in WebCron by setting a variable
with the value of microtime() at the start of execution and figuring out how
long the script can actually run for. Then, I stop executing a task if
there are less than a few seconds left on the clock so that there is ample
time to clean up gracefully. For more information:

http://barebonescms.com/documentation/webcron/

Then I expose a convenience function called WC_GetTimeLeft() to modules and
tasks that can use it to test to see how much time is left on the clock to
execute the script. The approach works quite well. As an example, I use
WC_GetTimeLeft() extensively in my WebCron Site Backup module that can
backup websites of any size over HTTP/HTTPS.

http://barebonescms.com/documentation/webcron_site_backup/

So, while it can and has been done, it does require a little extra work at
the start of the script and obviously isn't as accurate as a dedicated
function in PHP itself would be.

--
Thomas Hruska
CubicleSoft President

Barebones CMS is a high-performance, open source content management system
for web developers operating in a team environment.

An open source CubicleSoft initiative.
Your choice of a MIT or LGPL license.

http://barebonescms.com/