Try/Catch breaks PHP script - php

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...
}

Related

php: try catch / error freezes server script

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 ..

PHP CodeIgniter Errors not stopping execution of Try Blocks

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.

Where is the template for try-catch blocks stored?

Does anyone know where the code template for try-catch blocks is stored in Netbeans settings? The specific template I'm referring to is inserted when I type try { and then hit Enter. After I do that, the following code block appears:
try {
} catch (Exception $ex) {
}
I would like to insert a newline between the try block and the catch statement but I don't know how to change this. I tried going to Tools->Options->Editor->Code Templates but I couldn't find whatever causes the above block to expand.
With Tools->Options->Editor->Code Templates you are on the right way look up in the first column of the table the Abbreviation: trycatch then youll see bellow the editable template and do it as I show you, dont forget to apply chages:
try {
"new line" // this line here I have put it
${selection}${cursor}
} ${CATCH_STMTS uncaughtExceptionCatchStatements default="catch (Exception e) {}" editable=false}
I have test it on NetBeans IDE 8.1 RC2 (Build 201510122201) and after writing trycatch and press tab it generates:
try {
"new line"
} catch (Exception e) {
}
I hope it helps!!!!

How to prevent a try-catch error from stopping execution

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; }
}

Loggin' try-catch transactions

My code is
try{
$this->_db->beginTransaction();
$stmt = $this->_db->prepare("...");
$stmt->execute(array($var1, $var2));
...
} catch (Exception $e) {
$stmt->rollBack();
}
I want to log this action to my log file with a function
as you see this one meant to save errors in transaction. Another one should also save the succeeded attempts. BUT if I put them inside of try{} and catch{} they not working for some reason. outside it does work good but I'm not sure what exactly should I check here for true/false to see the result outside of try/catch.
Thanks for your answers. I'm just learning so my questions might be stupid. Sorry for this. =)
Update.
What I've tried to do is:
try{...
} catch (Exception $e) {
$stmt->rollBack();
file_put_contents(LOG_CONST, date("r")." UderID: ".$id." Error: ".$e->getMessage()."\n", FILE_APPEND);
}
And it didn't put anything.
Update 2
Not sure if I have to add a new details here or I should answer to myself... Anyway. Right now I'm trying this code
try{
$this->_db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$this->_db->beginTransaction();
$stmt = $this->_db->prepare
..................
$stmt->execute(array($var));
file_put_contents(DATACHANGE_LOG, date("r")." ".n307." UderID: ".$id."\n", FILE_APPEND);
$this->_db->commit();
} catch (Exception $e) {
file_put_contents(DATACHANGE_LOG, date("r")." Hello! \n", FILE_APPEND);
$stmt->rollBack();
}
I have a same result with valid and not valid data at my log file. It's the first row from try{} which means that rollback is not affective at file_put_contents. However if the data at queries not valid rollback working agains them and there is no changes at DB. But the row before rollback never works.
Errors are enabled but it doesn't show anything... I just can't give up I have to understand it...
Update 3
What is invalid data?
I've tried MySQL errors/table,row errors.
Why do I need this at all?
I'm learning and doing a lot of things that I don't need actually just to understand how it works. As I see now it throwing errors in MySQL itself so really not useful logger in this particular case. Anyway I've got my errors and here is it.
Working code:
try{
$this->_db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$this->_db->beginTransaction();
$stmt = $this->_db->prepare
QUERIES
$stmt->execute(array($var));
file_put_contents(DATACHANGE_LOG, date("r")." ".n307." UserID: ".$id."\n", FILE_APPEND);
$this->_db->commit();
}catch(PDOException $e){
file_put_contents(DATACHANGE_LOG, date("r")."Error". $e->getMessage()." UserID: ".$id."\n", FILE_APPEND);
if($this->_db->rollback())
header("Location: http://link");
}
header("Location: http://anotherlink");
There is nothing essentially different inside try..catch blocks. And your file writing code should be working the same way as outside, no difference.
The only issue I can think of is irrelevant to try..catch but to exceptions in general: a thrown exception terminates further code execution. Say, if there is an error in $stmt->rollBack(); - no code below will be executed. So, it's better to move a logger at the top of the block.

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