I've read this thread: php: catch exception and continue execution, is it possible?
Every answer suggests that a try catch will continue executing the script. Here is an example where it doesn't:
try{ $load = #sys_getloadavg(); }
catch (Exception $e){ echo 'Couldn\'t find load average.<br>'; return false; }
I'm running it on xampp on windows, which could be why it errors (it gives a Call to undefined function sys_getloadavg() error when the # is removed), but that isn't the issue in question. It could be any function that doesn't exist, isn't supported or fails - I can not get the script to continue executing.
Another example is if there is a syntax error in the try, say I'm including an external file and parsing it as an array. This also produces an error and stops executing.
Is there any brute force way to continue the script running, regardless of what fails in the try?
Unlike other languages, there's a difference in PHP between exceptions and errors. This would be like a compile error in other languages. that require declaration files. You can't catch or ignore Fatal errors like a function not exisiting. You can test for existence before using though:
if( function_exists('sys_getloadavg') {
try{ $load = #sys_getloadavg(); }
catch (Exception $e){ echo 'Couldn\'t find load average.<br>'; return false; }
}
Related
I am running a cronjob script which completely freezes within a try / catch statement (which is inside a while loop).
The catch phrase is working as it's logging the error (which i put there) but then it freezes completely without any output.
after that i only put echo "error"; inside the catch pharse but it does not output and freezes again.
when adding die; it prompts and the script stops as expected - but i want to catch the error and continue the script.
while($rs = $res->fetch_assoc())
{
try
{
$rc = new c_movie();
$result = $rc->search();
} catch(Throwable $t)
{
echo "ERROR!!!!"; // freezing here, does not echo
}
}
any idea what could be causing the script to freeze?
thanks
I finally found out by myself .. my code was using get_headers() which caused the freeze when trying to load a URL which had 404. Seems like the server is somekind of caching it and freezes and won't trigger the exception. Very Strange ..
I'm using CodeIgniter and am trying to execute code in a try/catch block with the idea that errors will stop execution of the code after the error until the catch block is reached, as you would normally think it would work.
However on encountering PHP Errors, the code is continuing. This is causing a database transaction complete command to execute which is .... very bad if there's an error and all of the instructions weren't carried out properly. For example, I have this code which is executed in an ajax request:
// start transaction
$this->db->trans_start();
try {
$this->M_debug->fblog("firstName=" . $triggerOpts->{'firstXXXName'});
$data = array("test_col" => 123);
$this->db->where("id", 4);
$this->db->update("my_table", $data);
// if got this far, process is ok
$status = "process_ok";
// complete transaction
$this->db->trans_complete();
} catch (Exception $ex) {
// output the error
$this->M_debug->logError($ex);
}
In this code, I'm trying to execute a database update as part of a transaction.
My call to $this->M_debug->fblog() is designed to just log a variable to PHP Console, and I've deliberately tried to log a variable that does not exist.
This causes a PHP error, which I guess is a fatal error, and the desired result is that the code after the log commands fails, and the transaction does not complete. However after this error, despite reporting the PHP error in Chrome console, the code keeps right on executing, the database is updated and the transaction is completed. Would appreciate any help in how i could stop this from happening.
Thanks very much, G
EDIT --
As requested heres fblog(), it's simply a Chrome console log request of a variable
public function fblog( $var ) {
ChromePhp::log( $var );
}
Assuming you're using PHP 7.0 or higher, you can catch PHP errors as well as exceptions, however you need to catch Error or the parent Throwable type rather than Exception.
try {
...
} catch (Throwable $ex) {
//this will catch anything, including Errors and Exceptions
}
or catch them separately if you want to do something different for each of them...
try {
...
} catch (Exception $ex) {
//this will catch Exceptions but not errors.
} catch (Error $ex) {
//this will Errors only
}
Note that if you're still only PHP 5.x, the above won't work; you can't catch PHP errors in older PHP versions.
SOLUTION: I've been working on the iOS side of it at the same time and must have got the languages switched up. Instead of the $, I put *.
I am trying to get a try{} catch{} working in PHP. My code works when I remove the try{} catch{}. Once I put it back in, it breaks my script. I even tried making it empty in both the try{} catch{}, but it still crashes my script.
try {
}
catch (Exception *e) {
}
Is there a reason the try{} catch{} would cause the script to crash? When I run it in my browser it just shows a white screen.
I even went and made another empty PHP file and put this code in without the if statement. And still, it doesn't work. The page is still white. I had it echo in the try.
Your catch declaration is incorrect.
catch (Exception *e) {
Should be.
catch (Exception $e) {
The inaccurate code would cause a parse error, thus preventing the script from running at all, and producing a white screen.
Maybe possibilities catch is not getting the object values. You should use it as:
try
{
some statement....
}
catch(Exception e)
{
some statement...
}
In PHP, when the script consume more than memory_limit value, the script stop with an error. How can I add a warning level: if my script consumes more than 90Mb I have a warning in the log file, but the script go on, and still crashes if it consumes more than 128Mb?
I know nothing about PHP extensions or PHP C code, but as long as we already build PHP by ourself, we can even patch the code.
In Zend/zend_alloc.c I can see this
if (segment_size < true_size || heap->real_size + segment_size > heap->limit) {
Really easy to add a line before this and compare used memory to another limit, and issue a warning.
Can I do this in an extension, or by patching the PHP code? Why this does not already exist? It is a bad idea? Does this already exist somewhere?
Adding the same warning for MAX_EXECUTION_TIME seem more difficult, as I still don't understand the way the timer is handled.
Here are some interesting questions / articles I have found for you:
This code shows a PHP way to catch a fatal error.
Safely catch a 'Allowed memory size exhausted' error in PHP
Basically you can use the PHP register_shutdown_function to run a function when the script exits or stops. And the function error_get_last() returns information about the last error, which would of been the fatal one:
ini_set('display_errors', false);
error_reporting(-1);
set_error_handler(function($code, $string, $file, $line){
throw new ErrorException($string, null, $code, $file, $line);
});
register_shutdown_function(function(){
$error = error_get_last();
if(null !== $error)
{
echo 'Caught at shutdown';
}
});
try
{
while(true)
{
$data .= str_repeat('#', PHP_INT_MAX);
}
}
catch(\Exception $exception)
{
echo 'Caught in try/catch';
}
I wouldn't recommend that you just edit the PHP C code. If you don't want to do this is PHP then you should really make an extension.
You could do it inside your php script using memory_get_usage(). It's not really at the system level and you'd have to call it several times while the script executes to catch the moment you use too much.
I am scratching my head trying to debug a PHP transaction that seems to error out one of my consumers. I can detect if my consumer is running by GREPping the process list, before I insert a new message, but no way of knowing what was in there before and what caused the fatal error.
My PHP consumer is roughly:
while($isRunning == true) {
try{
if($frame = $this->stomp->readFrame()) {
$body = $frame->body;
$this->stomp->ack($frame);
}
} catch(StompException $e) {
$msg = 'Stomp Monitor readFrame() Callback Fail: '.$e->getMessage();
error_log($msg);
}
}
Is there any way to catch fatal errors or anything that will break it out of the infinite loop?
Thanks,
Steve
Try setting a top level exception handler
Perhaps there is an exception that your not catching. Catch it and log it so you know why the process dies.