一個模擬瀏覽器請求的php類，模擬請求ua設置

<?php
/**
* http下載類庫
*/
/**
* 手機的UA:Mozilla/5.0 (Android; U; CPU OS 4_3_3 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5
*/
class Httplib{
// 目標網站無法打開時返回的錯誤代碼
var $_ERROR_CONNECT_FAILURE = 600;
// 自定義 UserAgent 字符串
var $_SEND_USER_AGENT = 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; LazyCMS.net::DownLoader)';
var $_url,$_method,$_timeout;
var $_scheme,$_host,$_port,$_path,$_query,$_referer;
var $_header;
var $_response;
/**
* 兼容PHP5模式
* 
* @param 同下面的參數
*/
function __construct($url=null,$method='GET',$timeout=60){
@set_time_limit(0);
if (!empty($url)) {
$this->connect($url,$method,$timeout);
}
return $this;
}
/**
* 初始化對象
*
* @param string $url
* @param string $method
* @param int $timeout
* @return object
*/
function Httplib($url=null,$method='GET',$timeout=60){
return $this->__construct($url,$method,$timeout);
}
/**
* 改變連接url
*
* @param string $url
* @param string $method
* @param int $timeout
* @return object
*/
function connect($url=null,$method='GET',$timeout=60){
$this->_header = null;
$this->_response = null;
$this->_url = $url;
$this->_method = strtoupper(empty($method) ? 'GET' : $method);
$this->_timeout = empty($timeout) ? 30 : $timeout;
if (!empty($url)) {
$this->_parseURL($url);
}
return $this;
}
/**
* 發送請求
* 
* @param array $params
* @return bool
*/ 
function send($params=array()) {
$header = null; $response = null; $QueryStr = null;
if (!empty($params)) { $this->_method = 'POST'; }
if (function_exists('fsockopen')) {
$fp = @fsockopen($this->_host,$this->_port,$errno,$errstr,$this->_timeout);
if (!$fp) { return false; }
$_port = ((int)$this->_port!==80) ? ':'.$this->_port : null;
$SendStr = "{$this->_method} {$this->_path}{$this->_query} HTTP/1.0\r\n";
$SendStr.= "Host:{$this->_host}{$_port}\r\n";
$SendStr.= "Accept: */*\r\n";
$SendStr.= "Referer:{$this->_referer}\r\n";
$SendStr.= "User-Agent: ".$this->_SEND_USER_AGENT."\r\n";
$SendStr.= "Pragma: no-cache\r\n";
$SendStr.= "Cache-Control: no-cache\r\n";
//如果是POST方法，分析參數
if ($this->_method=='POST') {
//判斷參數是否是數組，循環出查詢字符串
if (is_array($params)) {
$QueryStr = http_build_query($params);
} else {
$QueryStr = $params;
}
$length = strlen($QueryStr);
$SendStr.= "Content-Type: application/x-www-form-urlencoded\r\n";
$SendStr.= "Content-Length: {$length}\r\n";
}
$SendStr.= "Connection: Close\r\n\r\n";
if(strlen($QueryStr) > 0){
$SendStr.= $QueryStr."\r\n";
}
fputs($fp,$SendStr);
// 讀取 header
do{ $header.= fread($fp,1); } while (!preg_match("/\r\n\r\n$/",$header));
// 遇到跳轉，執行跟蹤跳轉
if ($this->_redirect($header)) { return true; }
// 讀取內容
while(!feof($fp)) {
$response.= fread($fp,4096);
}
fclose($fp);
} elseif (function_exists('curl_exec')) {
$ch = curl_init($this->_url);
curl_setopt_array($ch,array(
CURLOPT_TIMEOUT => $this->_timeout,
CURLOPT_HEADER => true,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_USERAGENT => $this->_SEND_USER_AGENT,
CURLOPT_REFERER => $this->_referer,
));
if ($this->_method=='GET') {
curl_setopt($ch,CURLOPT_HTTPGET,true);
} else {
if (is_array($params)) {
$QueryStr = http_build_query($params);
} else {
$QueryStr = $params;
}
curl_setopt($ch,CURLOPT_POST,true);
curl_setopt($ch,CURLOPT_POSTFIELDS,$QueryStr);
}
$fp = curl_exec($ch);
curl_close($ch);
if (!$fp) { return false; }
$i = 0; $length = strlen($fp);
// 讀取 header
do{ $header.= substr($fp,$i,1); $i++; } while (!preg_match("/\r\n\r\n$/",$header));
// 遇到跳轉，執行跟蹤跳轉
if ($this->_redirect($header)) { return true; }
// 讀取內容
do {
$response.= substr($fp,$i,4096);
$i = $i + 4096;
} while ($length>=$i);
unset($fp,$length,$i);
}
$this->_header = $header;
$this->_response = $response;
return true;
}
/**
* 跟蹤跳轉
*
* @param string $header
* @return bool
*/
function _redirect($header){
if (in_array($this->status($header),array(301,302))) {
if(preg_match("/Location\:(.+)\r\n/i",$header,$regs)){
$this->connect(trim($regs[1]),$this->_method,$this->_timeout);
$this->send();
return true;
}
} else {
return false;
}
}
/**
* 取得請求的header
*
* @return string
*/
function header(){
return $this->_header;
}
/**
* 請求返回的html
*
* @return string
*/
function response(){
return $this->_response;
}
/**
* 返回狀態
*
* @param string $header
* @return int
*/
function status($header=null){
if (empty($header)) {
$header = $this->_header;
}
if(preg_match("/(.+) (\d+) (.+)\r\n/i",$header,$status)){
return $status[2];
} else {
return $this->_ERROR_CONNECT_FAILURE;
}
}
/**
* 解析url
*
* @param string $url
*/
function _parseURL($url){
$aUrl = parse_url($url);
$aUrl['query'] = isset($aUrl['query']) ? $aUrl['query'] : null;
$scheme = isset($_SERVER['HTTPS']) ? $_SERVER['HTTPS'] : null;
$this->_scheme = ($scheme=='off' || empty($scheme)) ? 'http' : 'https';
$this->_host = isset($aUrl['host']) ? $aUrl['host'] : null;
$this->_port = empty($aUrl['port']) ? 80 : (int)$aUrl['host'];
$this->_path = empty($aUrl['path']) ? '/' : (string)$aUrl['path'];
$this->_query = strlen($aUrl['query']) > 0 ? '?'.$aUrl['query'] : null;
$this->_referer = $this->_scheme.'://'.$aUrl['host'];
}
}

$http = new Httplib('http://www.baidu.com');
$http->send();
$body = $http->response();
echo $body;