i try to make a function that load classes that are in the array. but it can be the case that the class don't exists, in that case i want to get an error string that an be places on that place and if it exists than the class has to be on that place.
so i thought i going to use try,catch to catch the error, but i stell get tge error.
try {
$content = $extension::content();
} catch (Exception $e) {
$content = '[undefined extension:'.$extension.']';
}
who can help me out
thanks
try using class_exists() documentation here
e.g
<?php
if( class_exists( $extension ) )
{
$content = $extension::content();
}else{
$content = '[undefined extension:'.$extension.']';
}
if ( class_exists($extension) && property_exists($extension, 'content') ) {
$content = $extension::content();
}else{
$content = '[undefined extension:'.$extension.']';
}
Since PHP5 you can autoload classes. As soon as you try to load a class that PHP does not know about it will run your custom function which will then be able to locate the class or throw an Exception of its non-existence.
Read about it here:
http://php.net/manual/en/language.oop5.autoload.php
In PHP, by default errors aren't exception and can't be catched. However, you can use set_exception_handler to throw an exception when a error occurs. Sadly, fatal error cannot be handled with this method.
To check if a class exists, you can call class_exists.
Related
I am implementing a plugin controller CLASS for client created custom plugins.
Since the names of the classes of each plugin could very well end up clashing with other plugins already installed, I want to make sure we don't get fatal errors when a new plugin comes in.
I want to report to the user that the new plugin is clashing with an already installed one.
So basically atm I testing with 2 files both containing exactly the same code and am getting:
Fatal error: Cannot declare class [myclassname], because the name is already in use
I have tried catching this with no success using:
try {
include_once $file;
} catch (ClosedGeneratorException|DOMException|ErrorException|IntlException|LogicException|BadFunctionCallException|BadMethodCallException|DomainException|InvalidArgumentException|LengthException|OutOfRangeException|PharException|ReflectionException|RuntimeException|OutOfBoundsException|OverflowException|PDOException|RangeException|UnderflowException|UnexpectedValueException|SodiumException $ex) {
echo "Unable to load file.";
}
All these I got from Lists of Throwable and Exception tree as of 7.2.0 in https://www.php.net/manual/en/class.exception.php
The manual specifies that:
The thrown object must be an instance of the Exception class or a
subclass of Exception. Trying to throw an object that is not will
result in a PHP Fatal Error.
Is it possible that this is not an object of instance/suclass of the Exception class?
What am I missing?
Short answer: no, you're not missing anything. Declaring a duplicate class name can't be caught in any version of PHP (including 8.0.0 as far as the alpha releases). See https://3v4l.org/2TLA3
For some additional background, PHP does sometimes move errors like these underneath the Throwable hierarchy, so that they can be detected at runtime. PHP 7 added support for catching an attempt to instantiate a missing class, and 7.3 added support for catching an attempt to extend a missing class. See https://3v4l.org/BDnm9 for a brief demo of those.
In the end, to avoid this fatal error I decide to parse the files for the first available class declaration using tokens as follows:
public function getClassInFile($filenpath) {
$src = $this->uncommentFile($filenpath);
$class ='';
if (preg_match('/class[\s\n]+([a-zA-Z0-9_]+)[\s\na-zA-Z0-9_]+\{/', $src, $matches)) {
$class = $matches[1];
}
return $class;
}
public function uncommentFile($filenpath) {
$fileStr = file_get_contents($filenpath);
$newStr = '';
$commentTokens = array(T_COMMENT);
if (defined('T_DOC_COMMENT'))
$commentTokens[] = T_DOC_COMMENT; // PHP 5
if (defined('T_ML_COMMENT'))
$commentTokens[] = T_ML_COMMENT; // PHP 4
$tokens = token_get_all($fileStr);
foreach ($tokens as $token) {
if (is_array($token)) {
if (in_array($token[0], $commentTokens))
continue;
$token = $token[1];
}
$newStr .= $token;
}
return $newStr;
}
In this way, I can check whether the class I am expecting to find is in there, or if the class in there already exists, thus avoiding to include_once altogether in these cases.
Problem solved.
I'm calling a method that I know could cause an error and I'm trying to handle the error by wrapping the code in a try/catch statement...
class TestController extends Zend_Controller_Action
{
public function init()
{
// Anything here happens BEFORE the View has rendered
}
public function indexAction()
{
// Anything `echo`ed here is added to the end of the View
$model = new Application_Model_Testing('Mark', 31);
$this->view->sentence = $model->test();
$this->loadDataWhichCouldCauseError();
$this->loadView($model); // this method 'forwards' the Action onto another Controller
}
private function loadDataWhichCouldCauseError()
{
try {
$test = new Application_Model_NonExistent();
} catch (Exception $e) {
echo 'Handle the error';
}
}
private function loadView($model)
{
// Let's pretend we have loads of Models that require different Views
switch (get_class($model)) {
case 'Application_Model_Testing':
// Controller's have a `_forward` method to pass the Action onto another Controller
// The following line forwards to an `indexAction` within the `BlahController`
// It also passes some data onto the `BlahController`
$this->_forward('index', 'blah', null, array('data' => 'some data'));
break;
}
}
}
...but the problem I have is that the error isn't being handled. When viewing the application I get the following error...
( ! ) Fatal error: Class 'Application_Model_NonExistent' not found in /Library/WebServer/Documents/ZendTest/application/controllers/TestController.php on line 23
Can any one explain why this is happening and how I can get it to work?
Thanks
use
if (class_exists('Application_Model_NonExistent')) {
$test = new Application_Model_NonExistent;
} else {
echo 'class not found.';
}
like #prodigitalson said you can't catch that fatal error.
An error and an exception are not the same thing. Exceptions are thrown and meant to be caught, where errors are generally unrecoverable and triggered with http://www.php.net/manual/en/function.trigger-error.php
PHP: exceptions vs errors?
Can I try/catch a warning?
If you need to do some cleanup because of an error, you can use http://www.php.net/manual/en/function.set-error-handler.php
Thats not an exception, thats a FATAL error meaning you cant catch it like that. By definition a FATAL should not be recoverable.
Exception and Error are different things. There is an Exception class, which you are using and that $e is it's object.
You want to handle errors, check error handling in php-zend framework. But here, this is a Fatal error, you must rectify it, can not be handled.
I'm testing some legacy code that extends the default php exception object. This code prints out a custom HTML error message.
I would like to mock this exception object in such a way that when the tested code generates an exception it will just echo the basic message instead of giving me the whole HTML message.
I cannot figure out a way to do this. It seems like you can test for explicit exceptions, but you can't change in a general way the behavior of an exception, and you also can't mock up an object that extends a default php functionality. ( can't think of another example of this beyond exceptions... but it would seem to be the case )
I guess the problem is, where would you attach the mocked object?? It seems like you can't interfere with 'throw new' and this is the place that the object method is called....
Or if you could somehow use the existing phpunit exception functionality to change the exception behavior the way you want, in a general way for all your code... but this seems like it would be hacky and bad....
EDIT: here is some code to make things clearer:
class FooTest extends PHPUnit_Framework_TestCase{
public function testBar(){
include '/path/to/file.php'; //generates exception
$this->assertTrue($baz);
}
}
...
//overridden exception class
class Foo_Exception extends ErrorException{
...
so, my question, is there a way to deal with this overriden class, without doing it on a case by case basis? what if I'm not testing the behavior of the exception, just the code that causes the exception?
I would first write a test that captures the exception generation behavior:
include '/path/to/file.php'; //generates exception
public function testCatchFooException() {
try {
$this->assertTrue($baz);
}
catch (Exception $expected) {
$this->assertEquals('This is expected html from exception', $expected->getMessage());
return;
}
$this->fail('An expected Exception has not been raised Foo_Excpetion.');
}
Now you can do several things with this coverage test. You can either fix up the exception, or fix the code that causes the exception.
Another thing you can do is wrap the entire file.php in a class:
class FooClass {
function runFoo() {
include '/path/to/file.php'; //generates exception
}
}
Then add tests while using extract method until you isolate exception.
[EDIT]
Here is some serious procedural legacy code:
<?php
require_once 'helper.php'; //helper file
function countNewMessages($user_id) {
}
function countNewOrders() {
}
function countNewReturns() {
}
function getDB($init = NULL) {
}
function getDisplay() {
}
getDisplay();
?>
And here is the wrapped class:
<?php
require_once ''; //helper file
class Displayer {
function countNewMessages($user_id) {
}
function countNewOrders() {
}
function countNewReturns() {
}
function getDB($init = NULL) {
}
function getDisplay() {
}
}
?>
And now I can test it:
function testGetDisplay() {
$display = new Displayer();
$this->assertEquals('html code', $display->getDisplay());
}
And test the individual functions in it. And if I can further sprout methods on it.
The above test would be considered a coverage test. There may be bugs in it, but that is what it does. So as I sprout methods the get more code coverage from tests by sprouting that I can make sure I don't break the output.
The extened PHP exception object "prints" a costum HTML error page? You mean its error message is an entire HTML page? That's not very clever...
What you can do about it is to replace the default exception handler (see this function), call getMessage on the exception and parse the HTML error page to extract the message. Then you can print the error message and kill the script. Like this (in PHP 5.3):
set_exception_handler(
function (Exception $e) {
die(parse_html_error_page($e->getMessage()));
}
);
OK, I misunderstood the question. If the script you're testing catches the error and then echoes an error page, then this has nothing to do with exceptions. You can use the ob_ family:
ob_start();
include $file;
$contents = ob_get_contents();
if (result_is_error($contents))
die(extract_error_from_result($contents));
else
echo $contents;
ob_end_clean();
Which would you recommend?
Return an error code, such as E_USER_ERROR from a function, and determine proper message higher up:
function currentScriptFilename()
{
if(!isset($_SERVER['SCRIPT_FILENAME']))
{
//This?
return E_USER_ERROR;
}
else
{
$url = $_SERVER['SCRIPT_FILENAME'];
$exploded = explode('/', $url);
return end($exploded);
}
}
Execute trigger_error() from the function, with a specific error message:
function currentScriptFilename()
{
if(!isset($_SERVER['SCRIPT_FILENAME']))
{
//Or this?
trigger_error('$_SERVER[\'SCRIPT_FILENAME\'] is not set.', E_USER_ERROR);
}
else
{
$url = $_SERVER['SCRIPT_FILENAME'];
$exploded = explode('/', $url);
return end($exploded);
}
}
I am not sure if I will regret having put a bunch of error messages in my functions further down the line, since I would like to use them for other projects.
Or, would you recommend something totally different?
Do not mix the matters.
Error notification and error handling are different tasks.
You have to use both methods simultaneously.
If you think that $_SERVER['SCRIPT_FILENAME'] availability is worth an error message, you can use trigger error. However PHP itself will throw a notice if you won't check it.
If you want to handle this error, just check this function's return value.
But I would not create a special function for this task.
So,
if (!$filename = basename($_SERVER['SCRIPT_FILENAME']) {
// do whatever you want to handle this error.
}
would be enough
Exceptions could be useful to handle errors, to know if we had any errors occurred.
A simple example:
try {
$filename = basename($_SERVER['SCRIPT_FILENAME'])
if (!$filename) throw new Exception("no filename");
$data = get_some_data_from_db() or throw new Exception("no data");
$template = new Template();
//Exception could be thrown inside of Template class as well.
}
catch (Exception $e) {
//if we had any errors
show_error_page();
}
$template->show();
3.Use exceptions.
If this is the route you are going, I'd rather recommend throwing Exceptions rather then returing an E_ERROR (E_USER_ERROR should be used), as this is just an integer, and possibly a totally valid return for your function.
Advantages:
- Throwing of an Exception cannot be interpreted as anything else then an error by mistake.
- You keep the possibility to add a descriptive error message, even though you don't handle the error at that point/
- You keep a backtrace in your Exception.
- You can catch specific exceptions at specific points, making the decision where in your project a specific type of error should be handled a lot easier.
If not using exceptions which you should be, use trigger_error().
If it is an error you'd like to deal with, try returning FALSE like a lot of the in built functions do.
If you do use exceptions, catch them like this
try {
whatever()
} catch (Exception $e) {
// handle however
}
I'm extending my previous question (Handling exceptions within exception handle) to address my bad coding practice.
I'm trying to delegate autoload errors to a exception handler.
<?php
function __autoload($class_name) {
$file = $class_name.'.php';
try {
if (file_exists($file)) {
include $file;
}else{
throw new loadException("File $file is missing");
}
if(!class_exists($class_name,false)){
throw new loadException("Class $class_name missing in $file");
}
}catch(loadException $e){
header("HTTP/1.0 500 Internal Server Error");
$e->loadErrorPage('500');
exit;
}
return true;
}
class loadException extends Exception {
public function __toString()
{
return get_class($this) . " in {$this->file}({$this->line})".PHP_EOL
."'{$this->message}'".PHP_EOL
. "{$this->getTraceAsString()}";
}
public function loadErrorPage($code){
try {
$page = new pageClass();
echo $page->showPage($code);
}catch(Exception $e){
echo 'fatal error: ', $code;
}
}
}
$test = new testClass();
?>
the above script is supposed to load a 404 page if the testClass.php file is missing, and it works fine, UNLESS the pageClass.php file is missing as well, in which case I see a
"Fatal error: Class 'pageClass' not found in D:\xampp\htdocs\Test\PHP\errorhandle\index.php on line 29" instead of the "fatal error: 500" message
I do not want to add a try/catch block to each and every class autoload (object creation), so i tried this.
What is the proper way of handling this?
Have you tried checking for pageClass early on in the process, since it seems to be necessary even to get the error page out? If it doesn't exist, and if you don't want to write the 404 page w/o any objects (e.g. just HTML), bombing out of execution where that class doesn't exist would seem to be a good path.
Hope that helps.
Thanks,
Joe