为什么此HTTP请求会不断循环？

Question

I'm probably overlooking something really obvious here.

Comments are in to help explain any library specific code.

public function areCookiesEnabled() {

        $random = 'cx67ds';

        // set cookie
        cookie::set('test_cookie', $random);

        // try and get cookie, if not set to false
        $testCookie = cookie::get('test_cookie', false);


        $cookiesAppend = '?cookies=false';

        // were we able to get the cookie equal ?
        $cookiesEnabled = ($testCookie === $random);

        // if $_GET['cookies'] === false , etc try and remove $_GET portion
        if ($this->input->get('cookies', false) === 'false' AND $cookiesEnabled) {
          url::redirect(str_replace($cookiesAppend, '', url::current())); // redirect 
          return false;
        }

        // all else fails, add a $_GET[]
        if ( ! $cookiesEnabled) {

          url::redirect(url::current().$cookiesAppend);
        }

        return $cookiesEnabled;

    }

Firstly, I wanted an easy way to check if cookies were enabled. I achieved this, but in the event of no cookies, there was an ugly ?cookies=false in the URL.

That was OK, but then if you reloaded the page and did have cookies enabled again, I wanted to redirect the user so it stripped off ?cookies=false in the URL (allowing the method to recheck and learn that cookies now are enabled.).

Answer 1

After $cookiesEnabled = ($testCookie === $random);, there are 4 cases:

1. $cookiesEnabled is true and $_GET['cookies'] === 'false' is true
2. $cookiesEnabled is true and $_GET['cookies'] === 'false' is false
3. $cookiesEnabled is false and $_GET['cookies'] === 'false' is true
4. $cookiesEnabled is false and $_GET['cookies'] === 'false' is false

Case 1 is handled by the first if block. The return statement is intended to handle cases 2 and 3; the second if block is intended to handle only case 4, but it catches both case 3 and 4. In case 3, the URL already has ?cookies=false, but since $cookiesEnabled is false, we redirect to add ?cookies=false, and cycle back into case 3.