I am trying to use exception handling in case a file does not exists. For example when I run the model method and pass a string usr (which I know there is no file with that name) . It gives me the following error message
Fatal error: Uncaught exception 'Exception' with message 'Usr.php was not found' in /app/core/controller.php on line 14
I can't figure out whats wrong here. Can someone please help me figure this out?
Below is my code. Thanks alot!
class Controllers{
public function model($model){
if(!file_exists("../app/models/".$model.".php")) {
throw new exception("{$model}.php was not found");
}
try {
require ("../app/models/".$model.".php");
} catch(Exception $e) {
echo $e->getMessage();
}
return new $model();
}
}
You can't throw an exception without catching it; this automatically causes the PHP script to crash. So, you need to surround your entire function in the try-catch block, or the "model not found" exception will be uncaught. Your code should be something like this:
<?php
class Controllers {
public function model($model){
try {
if (!file_exists("../app/models/".$model.".php")) {
throw new Exception("{$model}.php was not found");
}
require ("../app/models/".$model.".php");
} catch(Exception $e) {
echo $e->getMessage();
}
return new $model();
}
}
Never mind guys! I found out I needed to use the try/catch blocks in the file where my method is being invoked
Example..
class Home extends Controllers{
public function index($name = ""){
try{
$user = $this->model('Usr');
}catch (Exception $e){
echo $e->getMessage();
}
//var_dump($user);
}
Related
I found an really interesting problem on the internet about Exceptions & Errors, but I can't get it.
class MyException extends Exception {
public function __construct(string $message) {
$this -> message = $message;
}
}
class A {
public function __construct() {
throw new MyException("an error appeared");
}
}
$err = null;
try {
new A();
}
catch (MyException $err) {
throw new Exception('another error appeared');
}
catch (Exception $err) {
echo $err;
}
When I execute the code I receive
Fatal error: Uncaught Exception: another error appeared in C:\xampp
I don't understand if it's a problem about the code or this is how it works actually. Maybe you can help me.
That fatal error is for an untreated exception?
Thank you!
The second catch block does not catch the exception thrown in the first catch block. It can only be used to catch a an additional type of exception thrown in the first try block.
To catch your second exception you need to add a nested try catch:
try {
new A();
}
catch (MyException $err) {
try {
throw new Exception('another error appeared');
}
catch (Exception $err) {
echo $err;
}
}
Yes, the fatal error is for an unhandled exception here:
$err = null;
try {
new A();
}
catch (MyException $err) {
--->throw new Exception('another error appeared');
}
catch (Exception $err) {
echo $err;
}
In case you are wondering what is leading to this, it is this line in your code snippet:
$err = null;
try {
---> new A();
}
I'm having trouble catching an exception in PHP
Here's my code.
try {
require $this->get_file_name($action);
}
catch (Exception $e) {
//do something//
}
and the method being called
private function get_file_name($action) {
$file = '../private/actions/actions_'.$this->group.'.php';
if (file_exists($file) === false) {
throw new Exception('The file for this '.$action.' was not found.');
}
else {
return $file;
}
}
Resulting in:
Fatal error: Uncaught exception 'Exception' with message $action was not found.'
Exception: The file for this $action was not found.
However If I put a try-catch block inside of the function and call the function, I'm able to catch the exception no problem.
What am I doing wrong?
If you are catching the Exception inside a namespace, make sure that you fall back to the global namespace:
...
}(catch \Exception $e) {
...
}...
You can also have a look at the following resources:
Why isn't my Exception being caught by catch?
http://php.net/manual/en/language.exceptions.php, top note by user zmunoz
I can't see all of the class body but If You want to use method out of the class it should be Public not Private.
Try to check if file You trying to get exists:
var_dump($file = '../private/actions/actions_'.$this->group.'.php');
IMO there is no file in this path
My script_a.php:
try {
Class1::tryThis();
}
catch (Exception $e) {
// Do stuff here to show the user an error occurred
}
Class1::tryThis() has something like:
public function tryThis() {
Class2::tryThat();
self::logSuccessfulEvent();
}
The problem is that Class2::tryThat() can throw an exception.
If it does throw an exception, it seems that the line self::logSuccessfulEvent(); still gets executed.
How can I refactor this code so that self::logSuccessfulEvent() only occurs when an exception is not thrown, yet at the same time letting script_a.php know when an exception has been thrown?
This function will return whether or not the operation was successful (true = success, false = failure)
public function tryThis() {
$success = true;
try {
Class2::tryThat();
self::logSuccessfulEvent();
} catch( Exception $e) {
$success = false;
}
return $success;
}
What you're describing does not seem to be the case.
Code:
<?php
class Class1 {
public function tryThis() {
echo "Class1::tryThis() was called.\n";
Class2::tryThat();
self::logSuccessfulEvent();
}
public function logSuccessfulEvent() {
echo "Class1::logSuccessfulEvent() was called.\n";
}
}
class Class2 {
public function tryThat() {
echo "Class2::tryThat() was called.\n";
throw new Exception('Exception generated in Class2::tryThat()');
}
}
try {
Class1::tryThis();
} catch (Exception $e) {
echo $e->getMessage(), "\n";
}
Output:
Class1::tryThis() was called.
Class2::tryThat() was called.
Exception generated in Class2::tryThat()
As you can see, the Class1::logSuccessfulEvent() method is never executed when an exception is generated in Class2::tryThat(), and it shouldn't (won't) either. Exceptions bubble up until they are caught or produce a fatal error. Once an exception is caught, control of the program returns to the code after the catch block. In this particular case, that would mean that control of the program never reaches the logging method.
I am trying to understand what the best approach would be to handle Exceptions in the following scenario:
I have a class employee:
class employee extends person {
private $salary;
private $baseSalary = 6.5;
function __construct($f, $m, $l, $a,$fsalary=0){
if(!is_numeric($fsalary)){
throw new Exception("Age supplied is not a number", 114);
}
parent::__construct($f, $m, $l, $a);
$this->salary=$fsalary;
}
function GetDetails(){
return parent::GetName().
"<br/>".
$this->salary;
}
function __toString(){
return $this->GetDetails();
}
}
And using this:
try{
if(!$f = new employee("Sarah", "Sebastian", "Pira", "abc")){
throw new Exception();
}
else {
echo $f;
}
}
catch (Exception $e){
echo "<br/>";
echo var_dump($e);
}
Now I would think it would be a good idea to throw an exception in the class and then use just one catch block in all the scripts that would be using an employee object - But this doesn't seem to work - I need to have a try catch block within the class - Is this the correct way of looking at this?
Thanks
I think what you're saying is that you want to do something like this:
try {
class Employee extends Person {
// ...blah blah...
}
}
catch(Exception $e) {
// handle exception
}
...and then be able to insantiate it in other classes, without explicitly catching any exceptions:
// try { << this would be removed
$employee = new Employee();
// }
// catch(Exception $e) {
// (a whole bunch of code to handle the exception here)
// }
You can't do that, because then the try/catch block in the class will only catch any exceptions that occur when defining the class. They won't be caught when you try to instantiate it because your new Employee line is outside the try/catch block.
So really, your problem is that you want to be able to re-use a try/catch block in multiple places without re-writing the code. In that case, your best solution is to move the contents of the catch block out to a separate function that you can call as necessary. Define the function in the Employee class file and call it like this:
try {
$employee = new Employee();
$employee->doSomeStuff();
$employee->doMoreStuffThatCouldThrowExceptions();
}
catch(Exception $e) {
handle_employee_exception($e);
}
It doesn't get rid of the try/catch block in every file, but it does mean that you don't have to duplicate the implementation of the exception-handling all the time. And don't define handle_employee_exception as an instance method of the class, do it as a separate function, otherwise it will cause a fatal error if the exception is thrown in the constructor because the variable won't exist.
You should read more about Exceptions in PHP.
You can handle exceptions within the methods of the class, sure. But you should rethink how you want to do this and... why.
Good practice is also creating own exception class, so you are able to distinguish exceptions thrown by your module / class from the exceptions thrown by something else. It looks like that (see more):
class EmployeeModule_Exception extends Exception {}
and when it comes to throwing exception:
// the second parameter below is error code
throw new EmployeeModule_Exception('some message', 123);
Catching is similar, only the below example will catch only your module's exceptions:
try {
// some code here
} catch (EmployeeModule_Exception $e) {
// display information about exception caught
echo 'Error message: ' . $e->getMessage() . '<br />';
echo 'Error code: ' . $e->getCode();
}
I use PHPUnit DataBase to test some class using MDB2.
All is well, since I encounter the second test, which returns an error:
Caught exception: Object of class
MDB2_Error could not be converted to
string
When I place the second test in place of the first one, the new first test is OK, but the second one returns the same error!
And the next ones also!
Maybe the MDB2 connection is closed after the first test?
Here is my constructor:
public function __construct()
{
$this->pdo = new PDO('connectionstring', 'user', 'passwd');
try {
$this->mdb2 = new MyDBA($this->dsn);
}
catch (Exception $e) {
error_log(' __construct Caught exception: '.$e->getMessage());
}
}
MyDBA returns a singleton.
No exception is raised inside the constructor...
Here are the two first tests:
public function testTranslationAdd()
{
try {
$id = $this->mdb2->addTranslation("This is the second english translation.","en");
}
catch (Exception $e) {
error_log(' testTranslationAdd Caught exception: '.$e->getMessage());
}
$xml_dataset = $this->createFlatXMLDataSet(dirname(__FILE__).'/state/twotranslations.xml');
$this->assertDataSetsEqual($xml_dataset,
$this->getConnection()->createDataSet(array("translation")));
}
public function testTranslationGet()
{
try {
$text = $this->mdb2->getTranslation(1,"en");
}
catch (Exception $e) {
error_log(' testTranslationGet Caught exception: '.$e->getMessage());
}
$this->assertEquals("This is the first english translation.",$text);
}
You should really add assertions that your mdb2 result is no error:
$this->assertFalse(MDB2::isError($this->mdb2), 'MDB2 error');
That unfortunately does not give you any hint what the error is, and using getMessage() directly in the assertion will fail badly if you don't have an error. That why you should write something along that way:
if (MDB2::isError($this->mdb2)) {
$this->fail('MDB2 error: ' . $this->mdb2->getMessage());
}