[5.x] Respect the current site when returning a View

[aerni]

This PR fixes an issue where the current site wasn't resolved correctly when returning a view from an action route. Consider the following scenario:

Example

I'm returning a View in a controller from an action route.

return (new View)
    ->layout($layout)
    ->template($template)
    ->cascadeContent($data);

When the cascade() is hydrated in the View class, it will resolve the Cascade::instance()from the container, where it was bound with Site::current().

cms/src/View/View.php

Lines 188 to 194 in 5cb5da6

	protected function cascade()
	{
	return $this->cascade = $this->cascade ?? Cascade::instance()
	->withContent($this->cascadeContent)
	->hydrate()
	->toArray();
	}

cms/src/Providers/ViewServiceProvider.php

Lines 39 to 41 in 5cb5da6

	$this->app->singleton(Cascade::class, function ($app) {
	return new Cascade($app['request'], Site::current());
	});

At the time when the Cascade is bound in the container, the current site will be resolved from the current URL. Because we are on an action route, the resolved site will always be the default site.

cms/src/Sites/Sites.php

Lines 72 to 77 in 5cb5da6

	private function findByCurrentUrl()
	{
	return $this->findByUrl(
	$this->currentUrlCallback ? call_user_func($this->currentUrlCallback) : request()->getUri()
	);
	}

This leads to the View always being hydrated with data from the default site.

In my scenario, I rely on localized content being returned from the action route. To solve this, I figured that I could set the current site before returning the view:

Site::setCurrent($site);

return (new View)
    ->layout($layout)
    ->template($template)
    ->cascadeContent($data);

However, this won't work, as the Cascade was already bound with the site resolved from the current request before Site::setCurrent($site) is called.

To resolve this issue, we can explicitly set the current site using the withSite() method before the Cascade is hydrated in the cascade() method of the View class.

[jasonvarga]

Beautiful PR, thanks.