Slim ignoring try catch block - php

Question

I am using Slim to code a REST API, I have come upon a situation where I need to check if the date time entered by user is valid and thus came up with this code
$app->post('/test', function() use($app)
{
verifyRequiredParams(array('d_string'));
$response = array();
$d_string = $app->request->post('d_string');
try {
$datetime = datetime::createfromformat('d M Y H:i:s', $d_string);
$output = $datetime->format('d-M-Y H:i:s');
}
catch (Exception $e) {
$response["error"] = true;
$response["message"] = $e->getMessage();
echoRespnse(400,$response);
}
$response["error"] = false;
$response["message"] = "Converted Date";
$response['output'] = $output;
echoRespnse(200,$response);
});
It works fine when I enter a valid date time string like 11-Dec-2015 12:18 but if just for testing purpose I enter some random string, it gives 500 internal error instead of giving me any exception.
Why is it ignoring the try catch block???
Error Info
PHP Fatal error: Call to a member function format() on a non-object

Answer 1

DateTime::createFromFormat will not throw an exception if the provided time string is invalid, but will return a boolean false.
So you don't really need a try/catch block to accomplish this:
$datetime = \DateTime::createFromFormat('d M Y H:i:s', $d_string);
if (false === $datetime) {
// send your 400 response and exit
}
$output = $datetime->format('d-M-Y H:i:s');
// the rest of the code
If you really want to keep your try/catch block for various reasons, you can throw an exception yourself and catch it locally:
try {
$datetime = \DateTime::createFromFormat('d M Y H:i:s', $d_string);
if (false === $datetime) {
throw new \Exception('Invalid date.');
}
$output = $datetime->format('d-M-Y H:i:s');
} catch (\Exception $e) {
$response["error"] = true;
$response["message"] = $e->getMessage();
echoRespnse(400,$response);
}
But I don't see a really good reason to throw an exception just to catch it locally in this situation, so I would go with first solution.
If you want to show more detailed error messages, you can use DateTime::getLastErrors method.