Forcing page flow

Use the Session. Prevent viewing B if there is not some state in the Session that should be put there whenever visiting A

The easiest way would be to save a value in your user’s session data (or in a cookie), and then check in your controller whether the value is present and satisfies the required minimum of pages you’ve viewed.

You could either save that value when loading the page (i.e., when you load page 1, you save a value that corresponds to “user has opened page 1”), or when the user clicks on a “Next” button at the end of the page, if you want to ensure that the user has not only opened the page, but actually scrolled to the end of it as well, the way Google does on their terms and conditions popovers.

Personally, I would implement the check through an enum class that you do bitwise comparisons on to check, something like this:

enum PageStatus : int {
	case page1 	= 1 << 0; // 1
	case page2	= 1 << 1; // 2
	case page3	= 1 << 2; // 4
	case page4	= 1 << 3; // 8
	case page5	= 1 << 4; // 16

	public function satisfies($value) {
		return ($value + 1) & $this->value == $this->value;
	}
}

Then in your controller, you’d load the status from the session/cookie, and then check whether the current page’s status is satisfied by that.