我要评论把抓取到的内容转下编码即可($content=iconv("gbk", "utf-8//ignore", $content);)，我们这里讨论的是如何抓取开了gzip的页面。怎么判断呢？获取的头部当中有content-encoding: gzip说明内容是gzip压缩的。用firebug看一下就知道页面开了gzip没有。下面是用firebug查看我的博客的头信息，gzip是开了的。
请求头信息原始头信息
accept text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
accept-encoding gzip, deflate
accept-language zh-cn,zh;q=0.8,en-us;q=0.5,en;q=0.3
connection keep-alive
cookie __utma=225240837.787252530.1317310581.1335406161.1335411401.1537; __utmz=225240837.1326850415.887.3.utmcsr=google|utmccn=(organic)|utmcmd=organic|utmctr=%e4%bb%bb%e4%bd%95%e9%a1%b9%e7%9b%ae%e9%83%bd%e4%b8%8d%e4%bc%9a%e9%82%a3%e4%b9%88%e7%ae%80%e5%8d%95%20site%3awww.nowamagic.net; phpsessid=888mj4425p8s0m7s0frre3ovc7; __utmc=225240837; __utmb=225240837.1.10.1335411401
host www.nowamagic.net
user-agent mozilla/5.0 (windows nt 5.1; rv:12.0) gecko/20100101 firefox/12.0
下面介绍一些解决方案：
1. 使用自带的zlib库
如果服务器已经装了zlib库，用下面的代码可以轻易解决乱码问题。
$data = file_get_contents("compress.zlib://".$url);
2. 使用curl代替file_get_contents
function curl_get($url, $gzip=false){
$curl = curl_init($url);
curl_setopt($curl, curlopt_returntransfer, 1);
curl_setopt($curl, curlopt_connecttimeout, 10);
if($gzip) curl_setopt($curl, curlopt_encoding, "gzip"); // 关键在这里
$content = curl_exec($curl);
curl_close($curl);
return $content;
}
3. 使用gzip解压函数
function gzdecode($data) {
$len = strlen($data);
if ($len < 18 || strcmp(substr($data,0,2),"\x1f\x8b")) {
return null; // not gzip format (see rfc 1952)
}
$method = ord(substr($data,2,1)); // compression method
$flags = ord(substr($data,3,1)); // flags
if ($flags & 31 != $flags) {
// reserved bits are set -- not allowed by rfc 1952
return null;
}
// note: $mtime may be negative (php integer limitations)
$mtime = unpack("v", substr($data,4,4));
$mtime = $mtime[1];
$xfl = substr($data,8,1);
$os = substr($data,8,1);
$headerlen = 10;
$extralen = 0;
$extra = "";
if ($flags & 4) {
// 2-byte length prefixed extra data in header
if ($len - $headerlen - 2 < 8) {
return false; // invalid format
}
$extralen = unpack("v",substr($data,8,2));
$extralen = $extralen[1];
if ($len - $headerlen - 2 - $extralen < 8) {
return false; // invalid format
}
$extra = substr($data,10,$extralen);
$headerlen += 2 + $extralen;
}
$filenamelen = 0;
$filename = "";
if ($flags & 8) {
// c-style string file name data in header
if ($len - $headerlen - 1 < 8) {
return false; // invalid format
}
$filenamelen = strpos(substr($data,8+$extralen),chr(0));
if ($filenamelen === false || $len - $headerlen - $filenamelen - 1 < 8) {
return false; // invalid format
}
$filename = substr($data,$headerlen,$filenamelen);
$headerlen += $filenamelen + 1;
}
$commentlen = 0;
$comment = "";
if ($flags & 16) {
// c-style string comment data in header
if ($len - $headerlen - 1 < 8) {
return false; // invalid format
}
$commentlen = strpos(substr($data,8+$extralen+$filenamelen),chr(0));
if ($commentlen === false || $len - $headerlen - $commentlen - 1 < 8) {
return false; // invalid header format
}
$comment = substr($data,$headerlen,$commentlen);
$headerlen += $commentlen + 1;
}
$headercrc = "";
if ($flags & 1) {
// 2-bytes (lowest order) of crc32 on header present
if ($len - $headerlen - 2 < 8) {
return false; // invalid format
}
$calccrc = crc32(substr($data,0,$headerlen)) & 0xffff;
$headercrc = unpack("v", substr($data,$headerlen,2));
$headercrc = $headercrc[1];
if ($headercrc != $calccrc) {
return false; // bad header crc
}
$headerlen += 2;
}
// gzip footer - these be negative due to php's limitations
$datacrc = unpack("v",substr($data,-8,4));
$datacrc = $datacrc[1];
$isize = unpack("v",substr($data,-4));
$isize = $isize[1];
// perform the decompression:
$bodylen = $len-$headerlen-8;
if ($bodylen < 1) {
// this should never happen - implementation bug!
return null;
}
$body = substr($data,$headerlen,$bodylen);
$data = "";
if ($bodylen > 0) {
switch ($method) {
case 8:
// currently the only supported compression method:
$data = gzinflate($body);
break;
default:
// unknown compression method
return false;
}
} else {
// i'm not sure if zero-byte body content is allowed.
// allow it for now... do nothing...
}
// verifiy decompressed size and crc32:
// note: this may fail with large data sizes depending on how
// php's integer limitations affect strlen() since $isize
// may be negative for large sizes.
if ($isize != strlen($data) || crc32($data) != $datacrc) {
// bad format! length or crc doesn't match!
return false;
}
return $data;
}
使用：
$html=file_get_contents('//www.jb51.net/');
$html=gzdecode($html);
就介绍这三个方法，应该能解决大部分gzip引起的抓取乱码问题了。
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