JezK

Edit File: class-mixed-content-fixer.php

<?php
defined('ABSPATH') or die("you do not have access to this page!");

if (!class_exists('rsssl_admin_mixed_content_fixer')) {
    class rsssl_mixed_content_fixer
    {
        private static $_this;
        public $http_urls = array();
        public $mixed_content_fixer = false;
        public $hide_wordpress_version = false;

function __construct()
        {
            if (isset(self::$_this)) wp_die();

self::$_this = $this;
			$this->mixed_content_fixer = is_ssl() && rsssl_get_option('mixed_content_fixer', true );
			$this->hide_wordpress_version = rsssl_get_option('hide_wordpress_version' );
            if ( !is_admin() && ($this->mixed_content_fixer || $this->hide_wordpress_version )) {
                $this->handle_output_buffer();
            } else if ( is_admin() && is_ssl() && rsssl_get_option("admin_mixed_content_fixer") ) {
	            $this->mixed_content_fixer = true;
	            $this->handle_output_buffer();
            }
        }

/**
         *
         * add action hooks at the start and at the end of the WP process.
         *
         * @since  2.3
         *
         * @access public
         *
         */

public function handle_output_buffer()
        {
            /* Do not fix mixed content when call is coming from wp_api or from xmlrpc */
            if (defined('JSON_REQUEST') && JSON_REQUEST) return;
            if (defined('XMLRPC_REQUEST') && XMLRPC_REQUEST) return;

$this->build_url_list();

if ( is_admin() ) {
                add_action("admin_init", array($this, "start_buffer"), 100);
                add_action("shutdown", array($this, "end_buffer"), 999);
            } else {
                if ( rsssl_get_option("switch_mixed_content_fixer_hook") || (defined('RSSSL_CONTENT_FIXER_ON_INIT') && RSSSL_CONTENT_FIXER_ON_INIT)) {
                    add_action("init", array($this, "start_buffer"));
                } else {
                    add_action("template_redirect", array($this, "start_buffer"));
                }

add_action("shutdown", array($this, "end_buffer"), 999);
            }
        }

/**
         * Apply the mixed content fixer.
         *
         * @since  2.3
         *
         * @access public
         *
         */

public function filter_buffer($buffer)
        {
			if ( $this->mixed_content_fixer ) {
				$buffer = $this->replace_insecure_links($buffer);
			}
            return apply_filters("rsssl_fixer_output", $buffer );
        }

/**
         * Start buffering the output
         *
         * @since  2.0
         *
         * @access public
         *
         */

public function start_buffer()
        {
            ob_start(array($this, "filter_buffer"));
        }

/**
         * Flush the output buffer
         *
         * @since  2.0
         *
         * @access public
         *
         */
        public function end_buffer()
        {
            // Only flush if buffer level is above zlib's level
            // to avoid "failed to send buffer of zlib output compression" notice
            if (function_exists('wp_ob_end_flush_all')) {
                wp_ob_end_flush_all();
            }
        }

/**
         * Creates an array of insecure links that should be https and an array of secure links to replace with
         *
         * @since  2.0
         *
         * @access public
         *
         */

public function build_url_list()
        {
            $home = str_replace("https://", "http://", get_option('home') );
            $root = str_replace("://www.", "://", $home);
            $www = str_replace("://", "://www.", $root);

//for the escaped version, we only replace the home_url, not it's www or non www counterpart, as it is most likely not used
            $escaped_home = str_replace("/", "\/", $home);
            $this->http_urls = array(
                $www,
                $root,
                $escaped_home,
                "src='http://",
                'src="http://',
            );
        }

/**
         * Just before the page is sent to the visitor's browser, all homeurl links are replaced with https.
         *
         * @since  1.0
         *
         * @access public
         *
         */

public function replace_insecure_links($str)
        {
            //skip if file is xml
            if ( strpos( $str, "<?xml" ) === 0 ) {
				return $str;
            }

$search_array = apply_filters('rlrsssl_replace_url_args', $this->http_urls);
            $ssl_array = str_replace(array("http://", "http:\/\/"), array("https://", "https:\/\/"), $search_array);
            $str = str_replace($search_array, $ssl_array, $str);

//replace all http links except hyperlinks
            //all tags with src attr are already fixed by str_replace
            $pattern = array(
                '/url\([\'"]?\K(http:\/\/)(?=[^)]+)/i',
                '/<link [^>]*?href=[\'"]\K(http:\/\/)(?=[^\'"]+)/i',
                '/<meta property="og:image" [^>]*?content=[\'"]\K(http:\/\/)(?=[^\'"]+)/i',
                '/<form [^>]*?action=[\'"]\K(http:\/\/)(?=[^\'"]+)/i',
            );

$str = preg_replace($pattern, 'https://', $str);

/* handle multiple images in srcset */
            $str = preg_replace_callback('/<img[^\>]*[^\>\S]+srcset=[\'"]\K((?:[^"\'\s,]+\s*(?:\s+\d+[wx])(?:,\s*)?)+)["\']/', array($this, 'replace_src_set'), $str);
            return str_replace("<body", '<body data-rsssl=1', $str);
        }

/**
         * Helper function
         *
         * */

public function replace_src_set($matches) {
            return str_replace("http://", "https://", $matches[0]);
        }

}
}