Magento 2 – Change Admin URL from HTTPS to HTTP

There is a function just for that, called shouldUrlBeSecure located in app/code/core/Mage/Core/Model/Config.php on line 1477.

Here is the complete function:

/**
 * Check whether given path should be secure according to configuration security requirements for URL
 * "Secure" should not be confused with https protocol, it is about web/secure/*_url settings usage only
 *
 * @param string $url
 * @return bool
 */
public function shouldUrlBeSecure($url)
{
    if (!Mage::getStoreConfigFlag(Mage_Core_Model_Store::XML_PATH_SECURE_IN_FRONTEND)) {
        return false;
    }

    if (!isset($this->_secureUrlCache[$url])) {
        $this->_secureUrlCache[$url] = false;
        $secureUrls = $this->getNode('frontend/secure_url');
        foreach ($secureUrls->children() as $match) {
            if (strpos($url, (string)$match) === 0) {
                $this->_secureUrlCache[$url] = true;
                break;
            }
        }
    }

    return $this->_secureUrlCache[$url];
}

To see which URLs should be secure you can add a simple Mage::log($secureUrls) inside the if statement. This is what my log entry looked like:

2014-02-12T11:55:26+00:00 DEBUG (7): Mage_Core_Model_Config_Element Object
(
    [install] => /install/wizard/checkSecureHost
    [customer] => /customer/
    [sales] => /sales/
    [authorizenet_paygate] => /paygate/authorizenet_payment
    [checkout_onepage] => /checkout/onepage
    [checkout_multishipping] => /checkout/multishipping
    [paypal_express] => /paypal/express
    [paypal_standard] => /paypal/standard
    [paypal_express_callbackshippingoptions] => paypal/express/callbackshippingoptions
    [googlecheckout_redirect] => /googlecheckout/redirect/
    [googlecheckout_beacon] => /googlecheckout/api/beacon/
    [googlecheckout_api] => /googlecheckout/api/
    [review_customer] => /review/customer/
    [tag_customer] => /tag/customer/
    [wishlist] => /wishlist/
    [paypaluk_express] => /paypaluk/express
    [rss_catalog_review] => /rss/catalog/review
    [rss_order_new] => /rss/order/new
    [rss_catalog_notifystock] => /rss/catalog/notifystock
    [centinel] => /centinel/
    [newsletter_manage] => /newsletter/manage/
    [downloadable] => /downloadable/customer/
    [downloadable_download] => /downloadable/download/
    [ogone_api] => /ogone/api
    [persistent_onepage_register] => /persistent/index/saveMethod
    [checkout_cart] => /checkout/cart
    [storecredit_info] => /storecredit/info/
    [giftcard_customer] => /giftcard/customer/
    [enterprise_pbridge_pbridge] => /enterprise_pbridge/pbridge/
    [invitation] => /invitation/
)

Now to figure out how Magento switches HTTP to HTTPS I think you would most likely have dive into the Zend framework in the lib inside lib/Zend/Http/* because it contains files of most interest. Well, anyway hope this helped. Good luck!

Yes, This is the problem with windows. Windows uses "\" as separator, the array "directories" contains entries with "/" as separator, so the check will always fail.

So you need to fix this by replacing the separator in core file:

Magento\Framework\View\Element\Template\File\Validator

function isPathInDirectories replace below code in isPathInDirectories function

$realPath = str_replace('\\', '/', $this->fileDriver->getRealPath($path));