一个用PHP获取远程网址header头信息的方法,这在采集时很有用,他可以让你判断出来,远程文件或网页是否正常,是否是404页

有二种方法,

1.用php的函数get_headers

get_headers --  Fetches all the headers sent by the server in response to a HTTP request

Description

array get_headers ( string url [, int format] )

get_headers() returns an array with the headers sent by the server in response to a HTTP request. Returns FALSE on failure and an error of level E_WARNING will be issued.

If the optional format parameter is set to 1, get_headers() parses the response and sets the array's keys.

例子 1. get_headers() example

$url = 'http://www.example.com';

print_r(get_headers($url));

print_r(get_headers($url, 1));

?>

上例的输出类似于：

Array

(

[0] => HTTP/1.1 200 OK

[1] => Date: Sat, 29 May 2004 12:28:13 GMT

[2] => Server: Apache/1.3.27 (Unix)  (Red-Hat/Linux)

[3] => Last-Modified: Wed, 08 Jan 2003 23:11:55 GMT

[4] => ETag: "3f80f-1b6-3e1cb03b"

[5] => Accept-Ranges: bytes

[6] => Content-Length: 438

[7] => Connection: close

[8] => Content-Type: text/HTML

)

Array

(

[0] => HTTP/1.1 200 OK

[Date] => Sat, 29 May 2004 12:28:14 GMT

[Server] => Apache/1.3.27 (Unix)  (Red-Hat/Linux)

[Last-Modified] => Wed, 08 Jan 2003 23:11:55 GMT

[ETag] => "3f80f-1b6-3e1cb03b"

[Accept-Ranges] => bytes

[Content-Length] => 438

[Connection] => close

[Content-Type] => text/html

)

get_headers 是用来取得远程服务器的响应头信息的.用返回的第一个数组再加上正则就可以判断远程地址是否为200正常网页

2,用curl CURLOPT_NOBODY参数只抓取header头信息

curl函数真是个好东西,curl参数里有一项可以配置只抓取远程网页的header头信息

如下代码,加红的地方是关健,他指定了curl抓的内容中包含header头,并且不要body内容.

function get_header($url){

$ch  = curl_init();

curl_setopt($ch, CURLOPT_URL, $url);

curl_setopt($ch, CURLOPT_HEADER, true);

curl_setopt($ch, CURLOPT_NOBODY,true);

curl_setopt($ch, CURLOPT_RETURNTRANSFER,true);

curl_setopt($ch, CURLOPT_FOLLOWLOCATION,true);

curl_setopt($ch, CURLOPT_AUTOREFERER,true);

curl_setopt($ch, CURLOPT_TIMEOUT,30);

curl_setopt($ch, CURLOPT_HTTPHEADER, array(

'Accept: */*',

'User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)',

'Connection: Keep-Alive'));

$header = curl_exec($ch);

return $header;

}