How to make instant redirection in Laravel - symfony

Question

I want to make an instant redirection in my controller in Laravel.
I know I can use
public function show($page)
{
return Redirect::url('http://example.com');
}
but I want to repeat this code in many controllers adding condition for example I would like to do something like this:
public function show($page)
{
$totalPages = 100; // here calculating maximum page
if ($page < 2 || $page > $totalPages) {
return Redirect::url('http://example.com');
}
// rest of code here - should be run if condition is false
}
but I don't want to repeat code in each controller.
If I try put redirection code in other method (that could exist in base controller) it won't work because it doesn't return anything in main controller:
public function show($page)
{
$totalPages = 100; // here calculating maximum page
$this->checkPages($page, $totalPages, 'http://example.com');
// rest of code here - should be run if condition is false
}
public function checkPages($page, $totalPages, $url)
{
if ($page < 2 || $page > $totalPages) {
return Redirect::url($url);
}
}
How can I solve this issue?

Answer 1

After a while of digging it seems that for this purposes you should use send() method from Symfony\Component\HttpFoundation (Laravel RedirectResponse inherits from this class).
So you can modify checkPages method this way:
public function checkPages($page, $totalPages, $url)
{
if ($page < 2 or $page > $totalPages) {
Redirect::url($url)->send();
}
}
and it will make instant redirection.

Answer 2

You have to return the results of the method in the base controller.
return $this->checkPages($page, $totalPages, 'http://example.com');

Answer 3

I'd probably suggest that your checkPages method is trying to do too much. Would I expect checkPages (which maybe should be validatePageNumber() or similar) to return a redirect? No, I'd expect it to return true or false.
That gives you this as your logic:
/**
* Make sure the current page is between 1 and $lastPage
*
* #param int $page
* #param int $lastPage
* #return bool
*/
protected function validatePageNumber( $page, $lastPage ) {
return $page < 2 || $page > $lastPage;
}
and now your controller logic is trivial:
public function show( $page ) {
$totalPages = 100;
if ( ! $this->validatePageNumber( $page, $totalPages ) ) {
return Redirect::url( 'http://example.com' );
}
// rest of code here - should be run if condition is false
}
Now if we use quasi-English to read your code, you have a public method show($page) which shows a page: it sets the total number of pages, checks that $page is valid, and if not, redirects somewhere. All of this is control logic, and only control logic, which is what a controller should be doing.
Your validatePageNumber() can now be abstracted into a model, or better yet, a ServiceProvider, and it does one job: validates that a number is between 1 and n.