wordpress代码实现七牛云加速和远程图片云加速

在对应的主题functions.php文件中加入以下代

define("LOCAL_HOST","http://www.cooljun.cn");
define("CDN_HOST","http://img.cooljun.cn");
define("CDN_NAME","qiniu");
define("QN_HOST","http://wp.cooljun.cn");

add_action('wp_loaded','coojun_ob_start');
function coojun_ob_start() {
    add_action('generate_rewrite_rules','remote_image_generate_rewrite_rules');
    add_filter('query_vars',            'remote_image_query_vars');
    add_action('template_redirect',     'remote_image_template_redirect', 5);
    add_filter('the_content',           'cdn_content',1);
    ob_start('qiniu_cdn_replace');
}

function qiniu_cdn_replace($html){
    $local_host = 'http://www.cooljun.cn'; //博客域名
    $qiniu_host = 'http://img.cooljun.cn'; //七牛域名
    $cdn_exts   = 'js|css|png|jpg|jpeg|gif|ico'; //扩展名（使用|分隔）
    $cdn_dirs   = 'wp-content|wp-includes'; //目录（使用|分隔）
 
    $cdn_dirs   = str_replace('-', '\-', $cdn_dirs);
 
    if ($cdn_dirs) {
        $regex  =  '/' . str_replace('/', '\/', $local_host) . '\/((' . $cdn_dirs . ')\/[^\s\?\\\'\"\;\>\<]{1,}.(' . $cdn_exts . '))([\"\\\'\s\?]{1})/';
        $html = preg_replace($regex, $qiniu_host . '/$1$4', $html); 
    } else { 
        $regex = '/' . str_replace('/', '\/', $local_host) . '\/([^\s\?\\\'\"\;\>\<]{1,}.(' . $cdn_exts . '))([\"\\\'\s\?]{1})/';
        $html =  preg_replace($regex, $qiniu_host . '/$1$3', $html);
    }
    return $html;
}

// 远程图片的 Rewrite 规则，第三方插件需要 flush rewrite
function remote_image_generate_rewrite_rules($wp_rewrite){
    $new_rules[CDN_NAME.'/([^/]+)/image/([^/]+)\.([^/]+)?$']    = 'index.php?p=$matches[1]&'.CDN_NAME.'_image=$matches[2]&'.CDN_NAME.'_image_type=$matches[3]';
    $wp_rewrite->rules = $new_rules + $wp_rewrite->rules;
}

// 远程图片的 Query String 变量
function remote_image_query_vars($public_query_vars) {
    $public_query_vars[] = CDN_NAME.'_image';
    $public_query_vars[] = CDN_NAME.'_image_type';
    return $public_query_vars;
}

// 远程图片加载模板
function remote_image_template_redirect(){
    $remote_image       = get_query_var(CDN_NAME.'_image');
    $remote_image_type  = get_query_var(CDN_NAME.'_image_type');
    if($remote_image && $remote_image_type){
        global $post;
        $post   = get_post(get_query_var('p'));
        $md5    = get_query_var('qiniu_image');
        $type   = get_query_var('qiniu_image_type');

        if(!$post){
            wp_die('该日志不存在','该日志不存在',array( 'response' => 404 ));
        }
        $preg = preg_match_all('|<img.*?src=[\'"](.*?)[\'"].*?>|i', do_shortcode($post->post_content), $matches);
        $url = '';
        if ($preg) {
            foreach ($matches[1] as $image_url) {
                if($md5 == md5($image_url)){
                    $url = $image_url;
                    break;
                }
            }
        }
        if(!$url){
            wp_die('该日志没有图片','该日志没有图片',array( 'response' => 404 ));
        }

        if(isset($_GET['url']) && $_GET['url']){
            echo $url;
        }else{
            if($url){
                switch ($type) {
                    case 'jpg':
                        header('Content-Type: image/jpeg');
                        $img = imagecreatefromstring(file_get_contents($url));
                        imagejpeg($img,null,100);
                        break;

                    case 'png':
                        header("Content-Type: image/png");
                        $img = imagecreatefrompng($url);
                        $background = imagecolorallocate($img, 0, 0, 0);
                        imagecolortransparent($img, $background);
                        imagealphablending($img, false);
                        imagesavealpha($img, true);
                        imagepng($img);
                        break;

                    case 'gif':
                        header('Content-Type: image/gif');
                        $img = imagecreatefromgif($url);
                        imagegif($img);
                        break;
                    
                    default:
                        # code...
                        break;      
                }
            }else{
                wp_die('该日志没有图片','该日志没有图片',array( 'response' => 404 ));
            }
        }
        exit;
    }
}

function cdn_content($content){
    $cdn_content = preg_replace_callback('|<img.*?src=[\'"](.*?)[\'"].*?>|i','cdn_content_image',$content);
    return $cdn_content;
}

function cdn_content_image($matches){
    $img_url    = trim($matches[1]);
    if(empty($img_url)) return;
    $remote_img_url     = get_content_remote_img_url($img_url);
    $result = str_replace($img_url, $remote_img_url, $matches[0]);
    return $result;
}

// 获取远程图片
function get_content_remote_img_url($img_url){
    if(strpos($img_url, QN_HOST) === false&&strpos($img_url, LOCAL_HOST) === false && strpos($img_url, CDN_HOST) === false ){   // 默认不去抓取远程图片，要第三方 CDN 启用才会
        $img_type = strtolower(pathinfo($img_url, PATHINFO_EXTENSION));
        // if($img_type != 'gif'){
            $img_type   = ($img_type == 'png')?'png':'jpg';
            $img_url    = CDN_HOST.'/'.CDN_NAME.'/'.get_the_ID().'/image/'.md5($img_url).'.'.$img_type;
        // }
    }
    $img_url = str_replace(LOCAL_HOST, CDN_HOST, $img_url);
    return $img_url;
}