通过php 判断页面或图片是否经过gzip压缩

<?phpob_start('ob_gzhandler'); // 开启gzip，屏蔽则关闭$data = array(    array('name'=>'one','value'=>1),    array('name'=>'two','value'=>2),    array('name'=>'three','value'=>3)
);

header('content-type:application/json');echo json_encode($data);?>

<?php$url = 'http://www.example.com/';
var_dump(check_gzip($url));/**
 * 判断url是否经过gzip压缩
 * @param String  $url 来源
 * @param Boolean
 */function check_gzip($url){
    $header = get_headers($url, 1);    if(isset($header['Vary']) && $header['Vary']=='Accept-Encoding'){        return true;
    }    return false;
}?>

<?phpheader('content-type:image/jpeg');
ob_start('ob_gzhandler'); // 开启gzip，屏蔽则关闭echo file_get_contents('test.jpg');?>

<?php$url = 'http://www.example.com/';
var_dump(check_gzip($url));/**
 * 判断url是否经过gzip压缩
 * @param String  $url 来源
 * @param Boolean
 */function check_gzip($url){
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_HEADER, 1);         // 输出header信息
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); // 返回的信息不直接输出
    curl_setopt($ch, CURLOPT_ENCODING, '');      // 不限制编码类型
    $response = curl_exec($ch);    if(!curl_errno($ch)){        $info = curl_getinfo($ch);        // 获取header
        $header_size = $info['header_size'];        $header_str = substr($response, 0, $header_size);        $filter = array("\r\n", "\r");        $header_str = str_replace($filter, PHP_EOL, $header_str);        // 检查content-encoding
        preg_match('/Content-Encoding: (.*)\s/i', $header_str, $matches);        if(isset($matches[1]) && $matches[1]=='gzip'){            return true;
        }
    }    return false;
}?>