本文操作环境:windows7系统、PHP7.1版、DELL G3电脑
php如何只抓取网页头?
php获取网页header信息的4种方法
php获取网页header信息的方法多种多样,就php语言来说,我知道的方法有4种, 下面逐一献上。
方法一:使用get_headers()函数
推荐指数: ★★★★★
get_header方法最简单只要两行代码即可搞定。如下:
$thisurl = "http://www.lao8.org/";
print_r(get_headers($thisurl, 1));
得到的结果为:
Array
(
[0] => HTTP/1.1 200 OK
[Cache-Control] => max-age=86400
[Content-Length] => 76102
[Content-Type] => text/html
[Content-Location] => http://www.lao8.org/index.html
[Last-Modified] => Fri, 19 Jul 2013 03:52:30 GMT
[Accept-Ranges] => bytes
[ETag] => "50bc48643384ce1:5cb3"
[Server] => Microsoft-IIS/6.0
[X-Powered-By] => ASP.NET
[Date] => Fri, 19 Jul 2013 09:06:39 GMT
[Connection] => close
)
方法二:使用http_response_header
推荐指数: ★★★
http_response_headerf方法也很简单,仅三行:
$thisurl = "http://www.lao8.org";
$html = file_get_contents($thisurl );
print_r($http_response_header);
得到的结果为:
Array
(
[0] => HTTP/1.1 200 OK
[1] => Cache-Control: max-age=86400
[2] => Content-Length: 76102
[3] => Content-Type: text/html
[4] => Content-Location: http://www.lao8.org/index.html
[5] => Last-Modified: Fri, 19 Jul 2013 03:52:30 GMT
[6] => Accept-Ranges: bytes
[7] => ETag: "50bc48643384ce1:5cb3"
[8] => Server: Microsoft-IIS/6.0
[9] => X-Powered-By: ASP.NET
[10] => Date: Fri, 19 Jul 2013 09:06:41 GMT
[11] => Connection: close
)
方法三:使用stream_get_meta_data()函数
推荐指数: ★★★
使用stream_get_meta_data()代码也只需三行:
$thisurl = "http://www.lao8.org/";
$fp = fopen($thisurl, 'r');
print_r(stream_get_meta_data($fp));
得到的结果为:
Array
(
[wrapper_data] => Array
(
[0] => HTTP/1.1 200 OK
[1] => Cache-Control: max-age=86400
[2] => Content-Length: 76102
[3] => Content-Type: text/html
[4] => Content-Location: http://www.lao8.org/index.html
[5] => Last-Modified: Fri, 19 Jul 2013 03:52:30 GMT
[6] => Accept-Ranges: bytes
[7] => ETag: "50bc48643384ce1:5cb3"
[8] => Server: Microsoft-IIS/6.0
[9] => X-Powered-By: ASP.NET
[10] => Date: Fri, 19 Jul 2013 09:06:41 GMT
[11] => Connection: close
)
[wrapper_type] => http
[stream_type] => tcp_socket
[mode] => r+
[unread_bytes] => 1086
[seekable] =>
[uri] => http://www.lao8.org/
[timed_out] =>
[blocked] => 1
[eof] =>
)
第四种方法: 使用php的高级函数 CURL()来获取
推荐指数: ★★★★
上面的三种方法能获取一般的网页header信息,如果想要获取更详细的header信息比如网页是否启用了GZip压缩。这时候可以用php的高级函数curl()来获取。
使用curl获得header可以检测GZip压缩
先贴出代码:
<?php
$szUrl = 'http://www.lao8.org/';
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $szUrl);
curl_setopt($curl, CURLOPT_HEADER, 1); //输出header信息
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1); //不显示网页内容
curl_setopt($curl, CURLOPT_ENCODING, ''); //允许执行gzip
$data=curl_exec($curl);
if(!curl_errno($curl))
{
$info = curl_getinfo($curl);
$httpHeaderSize = $info['header_size']; //header字符串体积
$pHeader = substr($data, 0, $httpHeaderSize); //获得header字符串
$split = array("rn", "n", "r"); //需要格式化header字符串
$pHeader = str_replace($split, '<br>', $pHeader); //使用<br>换行符格式化输出到网页上
echo $pHeader;
}
?>
输出结果如下:
HTTP/1.1 200 OK
Cache-Control: max-age=86400
Content-Length: 15189
Content-Type: text/html
Content-Encoding: gzip
Content-Location: http://www.lao8.org/index.html
Last-Modified: Fri, 19 Jul 2013 03:52:28 GMT
Accept-Ranges: bytes
ETag: "0268633384ce1:5cb3"
Vary: Accept-Encoding
Server: Microsoft-IIS/6.0
X-Powered-By: ASP.NET
Date: Fri, 19 Jul 2013 09:27:21 GMT
可以看到使用curl获取到的header信息多了这行:Content-Encoding: gzip,网页启用了GZip压缩。