How to detect wrong URL using Joomla! System Plugin? - plugins

Question

I have developed a Joomla! system plugin.
I would like to detect wrong URL when that plugin is executed.
For example:
If I enter a URL "http://localhost/wrong-url", I want to catch that error in the system plugin.
How do I know that the system will display the error page (404)?

Answer 1

You can do this using the following technique
Check URL Function
function checkURL($URL){
$ch = curl_init($URL);
curl_setopt($ch, CURLOPT_TIMEOUT, 5);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$data = curl_exec($ch);
$httpcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);
if ($httpcode != 200) {
return false;
}else{
return true;
}
}
Use Of the CheckURL Function
/*URL May be a Joomla OR Non Joomla Site*/
if(checkURL("http://adidac.github.com/jmm/index.html")){
echo "URL Exist";
}else{
echo "URL NOT Exist";
//JError::raiseWarning(500,$URL. " is not exists");
}
if(checkURL("http://adidac.github.com/jmm/indexsdadssdasaasdaas.html")){
echo "URL Exist";
}else{
echo "URL NOT Exist";
//JError::raiseWarning(500,$URL. " is not exists");
}
NOTE: Check you have PHP curl lib installed

Answer 2

In a system plugin to trap the 404 you would have to add a function from your plugin as a callback to JError error handler array.
I would have a look at the way com_redirect does it, with it's system plugin. e.g.
function __construct(&$subject, $config)
{
parent::__construct($subject, $config);
// Set the error handler for E_ERROR to be the class handleError method.
JError::setErrorHandling(E_ERROR, 'callback', array('plgSystemRedirect', 'handleError'));
}
static function handleError(&$error)
{
// Get the application object.
$app = JFactory::getApplication();
// Make sure we are not in the administrator and it's a 404.
if (!$app->isAdmin() and ($error->getCode() == 404))
{
// Do cool stuff here
}
}
The only problem is JError is depreciated so I'm not sure going forward when this would break e.g. it should be fine in 3.0, 3.1, 3.2 and 3.5 but after that who knows?

Answer 3

I know this is an old question, but I needed a solution today and found this question, so leaving my solution below to help anyone else searching in the future.
In the plugin file:
/**
* The global exception handler registered before the plugin was instantiated
*
* #var callable
* #since 3.6
*/
private static $previousExceptionHandler;
/**
* Constructor.
*
* #param object &$subject The object to observe
* #param array $config An optional associative array of configuration settings.
*
* #since 1.6
*/
public function __construct(&$subject, $config) {
parent::__construct($subject, $config);
// Register the previously defined exception handler so we can forward errors to it
self::$previousExceptionHandler = set_exception_handler(array('PlgSystemVmsreporting', 'handleException'));
}
public static function handleException($exception) {
// Wrap in try/catch to prevent any further exceptions being raised
try {
// Do whatever you need with the error
} catch (Exception $e) {
//Don't make a fuss - fail silently
}
// Proxy to the previous exception handler if available, otherwise use the default Joomla handler
if (self::$previousExceptionHandler) {
call_user_func_array(self::$previousExceptionHandler, array($exception));
} else {
ExceptionHandler::render($exception);
}
}