PHP won't catch error inside class, only on caller - php

I'm trying to catch an error from my JWT class but i can't do it inside the class, the only place i can get it is from my main caller.
I'm calling this class with the error from my "API" where i start with the routing:
$router = new Router();
$router->all('/users', function()
{
$controller = new Controllers\UserController();
$controller->start();
});
$router->run();
After that i have my controller that will call my "API" class:
class UserAPI extends BaseAPI
{
protected $user;
protected $apiBase = "user";
function __construct($request, $origin)
{
parent::__construct($request);
$this->user = new User();
}
protected function logout()
{
if( isset($this->request[$this->apiBase . 'Data']) )
{
return $this->usuario->login($this->request[$this->apiBase . 'Data']);
}
else
{
return Helpers::errorResponse("User data not informed", 200);
}
}
}
And finally i have the problem, the User class where i want to catch an error but it wont work:
class User extends SimpleModel
{
public function logout($userData)
{
try
{
//At this point i will get an error since the provided token is invalid on purpose
$jwt = JWT::decode($userData['token'], SECRET_KEY, ['HS512']);
}
//Wont hit here even for a miracle
catch (Exception $exception)
{
echo "Caught ExceptFoo\n";
echo "Message: {$exception->getMessage()}\n";
}
}
}
The only place i could catch this error was on the routing file, wich is my index.php file.
For the JWT class i'm using Firebase JWT.

Relative class names (like Exception in your example) are always rooted to the namespace you are within. If you don't define a namespace, \ is used. Consider:
<?php
namespace Foo;
use Vendor\Package\Bar;
try {
Bar::throwAnException();
} catch (Exception $ex) {
die((string)$ex);
}
Here we have two relative class paths: Bar and Exception. PHP resolves Bar via the use statement to the absolute class path \Vendor\Package\Bar. PHP doesn't have a use statement corresponding to Exception, so PHP assumes you mean \Foo\Exception.
Clearly this isn't your intent. Unfortunately, PHP is silent when this situation occurs. It's bitten me a few times.

Related

Symfony 4, how return properly a error 500 server from a service Class

From a Service class, how manage exceptions and return an error 500 ?
By example, I have a service class 'A' called from another service Class 'B'. The content of the service 'A' is :
namespace App\Service;
use ...
class A
{
...
public static function foo(){
$tmp = [];
// do some stuff
if(isOK($tmp)){
return $tmp;
}else{
// return 500 with message
}
}
private static function isOK($tmp){
// do some stuff
}
}
I tried this :
namespace App\Service;
use ...
class A
{
...
public static function foo(){
$tmp = [];
// do some stuff
if(isOK($tmp)){
return $tmp;
}else{
// return 500 with message
}
}
private static function isOK($tmp){
try{
if(...) throw new \Exception();
}catch (HttpException $e){
dump('not valid data $tmp var in ' . __FUNCTION__,500);
exit;
}
}
}
But I don't think I use a good way. If I deliberately set a wrong value to the $tmp var, the process is stopped (as I want) and, in a case where I use this service for build a symfony http web page, a blank page is displayed with my message but this page get a status 200 (not a 500 'internal server error').
What is the good/properly way for return an exception from a Service ?
Is there a global (symfony ? oop php?) way for manage properly errors exceptions in the 'service called from another service' context and/or in the 'service called from a controller used only for REST web service' context and/or , more conventionally, in the 'service called from a classical http controller' context ? (bonus : and/or in the "service called from a custom Command Class")
Maybe I completely misunderstand the question, but I'd say: throw an Exception from your Service.
But: you only catch an Exception, if you can properly handle it. In your case it looks as if you can't handle it in your Service, so you let it bubble up its way to the appropriate Symfony component (that differs between Console command, Controller or Rest endpoint).
The Service shouldn't set the 500 code, as it doesn't know in which context it is used. Therefor you might want to throw an explicit ServiceException and catch that in your controller and convert it to something more useful:
class A
{
public function foo(){
$tmp = [];
if($this->isOK($tmp)){
return $tmp;
}
throw new ServiceException('Failed checking $tmp');
}
private function isOK($tmp){
return false;
}
}
class TestController
{
/**
* #var A
*/
protected $a;
public function fooAction() {
try {
$this->a->foo();
} catch (ServiceException $e) {
throw new HttpException(500, $e->getMessage())
}
}
}
For web and rest you have to make sure that your Exception has the correct code, which will then be used to set the HTTP code.
Only the code that uses the service knows how to handle the Exception properly. As the status code doesn't matter in your console command, you could not catch it.
But in general you can say that this is not best practice, as you might have to do some cleanup (close connections, close file handles, write error log) before the Exception is passed to the next code level.
An example for the console:
class MyCommand extends Command
{
protected function execute(InputInterface $input, OutputInterface $output)
{
$io = new SymfonyStyle($input, $output);
$a = new A();
try {
$this->a->foo();
} catch (ServiceException $e) {
// write to log file
$io->error('Service failed: ' . $e->getMessage());
return;
}
// do more stuff
}
}

Uncaught exception when passing exception up through class

I have a class named User that calls one of its own methods, setUsername(), upon construction, within a try/catch block. If setUsername() fails, it will throw an exception:
class User {
private $username;
public function __construct($input_username) {
try {
$this->setUsername($input_username);
} catch(Exception $e) {
throw $e;
}
}
private function setUsername($username) {
if(1 != 0)
throw new Exception("1 does not equal 0!!!");
$this->username = $username;
}
}
I then create a new User in an external function, in a separate file, within its own try/catch block. It's supposed to catch the exception passed through from the User class constructor:
namespace UserController;
function createUser(){
try {
$user = new \User('sample-user');
} catch(Exception $e) {
echo $e->getMessage();
}
}
Why, then, am I still getting an "Uncaught Exception" error?
It seems I was missing a statement at the top of the file that instantiates the class, since it is namespaced. After the namespace declaration, it needs to say:
use \Exception;

Why all method in PHP Exception class are final?

I tried to override the getMessage() to give the return message a default value but failed because all method in PHP Exception class are final.
Now I am just curious about why it is. I know I can work it around by adding a proxy method.
They are final to make sure they work in the exact same way in all inherited classes. A programmer will expect getMessage to work in the exact same way for all classes inherited directly or transitively from Exception. You can set the message in the constructor though, as you will be able to write your own constructor for your class.
I have the impression that you want a pattern like this:
<?php
class UserNotFoundException extends \RuntimeException {
const MESSAGE_TEMPLATE = 'Could not find the requested user: %s';
public static function fromId($user_id) {
$message = sprintf(self::MESSAGE_TEMPLATE, "ID=$user_id");
return new self($message);
}
public static function fromName($name) {
$message = sprintf(self::MESSAGE_TEMPLATE, "name=$name");
return new self($message);
}
}
try {
throw UserNotFoundException::fromId(314);
} catch (RuntimeException $e) {
echo $e->getMessage() . PHP_EOL;
}
try {
throw UserNotFoundException::fromName('john');
} catch (RuntimeException $e) {
echo $e->getMessage() . PHP_EOL;
}
Could not find the requested user: ID=314
Could not find the requested user: name=john
Tweak it to your exact needs. This is quite practical for reuse and does not risk interfering with the overall exception mechanism.
Write your own Exception.
class MyException extends \Exception
{
}

Can one call an instance's method inside a class without recreating the instance within class' scope?

I'm relatively new to PHP, I'm trying to make a script to log errors from try/catch blocks. I've run into a scope problem trying to do so.
First, I attempted to make the class instance a global variable but that didn't work.
I know it is possible to make a new instance each time 'AnotherClass' is called; however, that would clear the '$errors' array in 'errorhandler'.
I've been stuck on this issue for a few hours and any help would be greatly appreciated!
<?php
class errorhandler
{
private $errors = [];
function log($e = '')
{
print "Opps! An error occured: " . $e;
array_push($this->errors, $e);
}
}
# global $errorhandler; # Doesn't work...
$errorhandler = new errorhandler();
class AnotherClass
{
function __construct()
{
try {
$not_possible = 1/0;
} catch (Exception $e) {
$errorhandler->log($e); # Doesn't work
}
}
}
new AnotherClass();
?>
Thanks :)
You have to import the global $errorhandler variable into your local scope:
class AnotherClass
{
function __construct()
{
global $errorhandler;
try {
$not_possible = 1/0;
} catch (Exception $e) {
$errorhandler->log($e); # Doesn't work
}
}
}
P.S. 1/0 is not an exception, it's a runtime error. You can't catch those with a try/catch block.

Why doesn't PHP catch a "Class not found" error?

In the following example, if the class does not exist, I want to catch the error and create a Null class instead.
But in spite of my try/catch statements, PHP simply tells me Class 'SmartFormasdfasdf' not found.
How can I get PHP to catch the 'class not found' error?
<?php
class SmartFormLogin extends SmartForm {
public function render() {
echo '<p>this is the login form</p>';
}
}
class SmartFormCodeWrapper extends SmartForm {
public function render() {
echo '<p>this is the code wrapper form</p>';
}
}
class SmartFormNull extends SmartForm {
public function render() {
echo '<p>the form "' . htmlentities($this->idCode) . '" does not exist</p>';
}
}
class SmartForm {
protected $idCode;
public function __construct($idCode) {
$this->idCode = $idCode;
}
public static function create($smartFormIdCode) {
$className = 'SmartForm' . $smartFormIdCode;
try {
return new $className($smartFormIdCode);
} catch (Exception $ex) {
return new SmartFormNull($smartformIdCode);
}
}
}
$formLogin = SmartForm::create('Login');
$formLogin->render();
$formLogin = SmartForm::create('CodeWrapper');
$formLogin->render();
$formLogin = SmartForm::create('asdfasdf');
$formLogin->render();
?>
Solution:
Thanks #Mchl, this is how I solved it then:
public static function create($smartFormIdCode) {
$className = 'SmartForm' . $smartFormIdCode;
if(class_exists($className)) {
return new $className($smartFormIdCode);
} else {
return new SmartFormNull($smartFormIdCode);
}
}
Because it's a fatal error. Use class_exists() function to check if class exist.
Also: PHP is not Java - unless you redefined default error handler, it will raise errors and not throw exceptions.
Old question, but in PHP7 this is a catchable exception. Though I still think the class_exists($class) is a more explicit way to do it. However, you could do a try/catch block using the new \Throwable exception type:
$className = 'SmartForm' . $smartFormIdCode;
try {
return new $className($smartFormIdCode);
} catch (\Throwable $ex) {
return new SmartFormNull($smartformIdCode);
}
php >= 7.0
php can catch 'class not found' as Throwable
try {
return new $className($smartFormIdCode);
} catch (\Throwable $ex) {
return new SmartFormNull($smartformIdCode);
}
You need to use class_exists to see if the class exists before you try and instantiate it.
Incidentally, if you're using a class autoloader, be sure to set the second arg to true.
Because php emits fatal error when you ty to create new object of non existing class. To make it work you will need php >= 5.3 and autoload function, where you should try to look for file with class definition or throw your custom exception.

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