php下载远程文件类支持断点续传

<?php 
/**
 * 下载远程文件类支持断点续传
 * 整理：www.jb200.com
 */ 
class HttpDownload { 
private $m_url = ""; 
private $m_urlpath = ""; 
private $m_scheme = "http"; 
private $m_host = ""; 
private $m_port = "80"; 
private $m_user = ""; 
private $m_pass = ""; 
private $m_path = "/"; 
private $m_query = ""; 
private $m_fp = ""; 
private $m_error = ""; 
private $m_httphead = "" ; 
private $m_html = ""; 
  
/**
 * 初始化 
 */ 
public function PrivateInit($url){ 
$urls = ""; 
$urls = @parse_url($url); 
$this->m_url = $url; 
if(is_array($urls)) { 
$this->m_host = $urls["host"]; 
if(!empty($urls["scheme"])) $this->m_scheme = $urls["scheme"]; 
if(!empty($urls["user"])) $this->m_user = $urls["user"]; 
if(!empty($urls["pass"])) $this->m_pass = $urls["pass"]; 
if(!empty($urls["port"])) $this->m_port = $urls["port"]; 
if(!empty($urls["path"])) $this->m_path = $urls["path"]; 
$this->m_urlpath = $this->m_path; 
if(!empty($urls["query"])) { 
$this->m_query = $urls["query"]; 
$this->m_urlpath .= "?".$this->m_query; 
} 
} 
} 
  
/**
* 打开指定网址
*/ 
function OpenUrl($url) { 
#重设各参数 
$this->m_url = ""; 
$this->m_urlpath = ""; 
$this->m_scheme = "http"; 
$this->m_host = ""; 
$this->m_port = "80"; 
$this->m_user = ""; 
$this->m_pass = ""; 
$this->m_path = "/"; 
$this->m_query = ""; 
$this->m_error = ""; 
$this->m_httphead = "" ; 
$this->m_html = ""; 
$this->Close(); 
#初始化系统 
$this->PrivateInit($url); 
$this->PrivateStartSession(); 
} 
 
/**
* 获得某操作错误的原因
*/ 
public function printError() { 
echo "错误信息：".$this->m_error; 
echo "具体返回头：<br>"; 
foreach($this->m_httphead as $k=>$v) {  
echo "$k => $v <br>rn";  
} // www.jb200.com
} 
  
/**
* 判别用Get方法发送的头的应答结果是否正确
*/ 
public function IsGetOK() { 
if( ereg("^2",$this->GetHead("http-state")) ) {  
return true;  
} else { 
$this->m_error .= $this->GetHead("http-state")." - ".$this->GetHead("http-describe")."<br>"; 
return false; 
} 
} 
 
/**
* 看看返回的网页是否是text类型
*/ 
public function IsText() { 
if (ereg("^2",$this->GetHead("http-state")) && eregi("^text",$this->GetHead("content-type"))) {  
return true;  
} else { 
$this->m_error .= "内容为非文本类型<br>"; 
return false; 
} 
} 
/**
* 判断返回的网页是否是特定的类型
*/ 
public function IsContentType($ctype) { 
if (ereg("^2",$this->GetHead("http-state")) && $this->GetHead("content-type") == strtolower($ctype)) {  
return true;  
} else { 
$this->m_error .= "类型不对 ".$this->GetHead("content-type")."<br>"; 
return false; 
} 
} 
 
/**
* 用 HTTP 协议下载文件
*/ 
public function SaveToBin($savefilename) { 
if (!$this->IsGetOK()) return false; 
if (@feof($this->m_fp)) {  
$this->m_error = "连接已经关闭！";  
return false;  
} 
$fp = fopen($savefilename,"w") or die("写入文件 $savefilename 失败！"); 
while (!feof($this->m_fp)) { 
@fwrite($fp,fgets($this->m_fp,256)); 
} 
@fclose($this->m_fp); 
return true; 
} 
 
/**
* 保存网页内容为 Text 文件
*/ 
public function SaveToText($savefilename) { 
if ($this->IsText()) { 
$this->SaveBinFile($savefilename); 
} else { 
return ""; 
} 
} 
 
/**
* 用 HTTP 协议获得一个网页的内容
*/ 
public function GetHtml() { 
if (!$this->IsText()) return ""; 
if ($this->m_html!="") return $this->m_html; 
if (!$this->m_fp||@feof($this->m_fp)) return ""; 
while(!feof($this->m_fp)) { 
$this->m_html .= fgets($this->m_fp,256); 
} 
@fclose($this->m_fp); 
return $this->m_html; 
} 
 
/**
* 开始 HTTP 会话
*/ 
public function PrivateStartSession() { 
if (!$this->PrivateOpenHost()) { 
$this->m_error .= "打开远程主机出错!"; 
return false; 
} 
if ($this->GetHead("http-edition")=="HTTP/1.1") { 
$httpv = "HTTP/1.1"; 
} else { 
$httpv = "HTTP/1.0"; 
} 
fputs($this->m_fp,"GET ".$this->m_urlpath." $httpvrn"); 
fputs($this->m_fp,"Host: ".$this->m_host."rn"); 
fputs($this->m_fp,"Accept: */*rn"); 
fputs($this->m_fp,"User-Agent: Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.2)rn"); 
#HTTP1.1协议必须指定文档结束后关闭链接,否则读取文档时无法使用feof判断结束 
if ($httpv=="HTTP/1.1") { 
fputs($this->m_fp,"Connection: Closernrn"); 
} else { 
fputs($this->m_fp,"rn"); 
} 
$httpstas = fgets($this->m_fp,256); 
$httpstas = split(" ",$httpstas); 
$this->m_httphead["http-edition"] = trim($httpstas[0]); 
$this->m_httphead["http-state"] = trim($httpstas[1]); 
$this->m_httphead["http-describe"] = ""; 
for ($i=2;$i<count($httpstas);$i++) { 
$this->m_httphead["http-describe"] .= " ".trim($httpstas[$i]); 
} // www.jb200.com
while (!feof($this->m_fp)) { 
$line = str_replace(""","",trim(fgets($this->m_fp,256))); 
if($line == "") break; 
if (ereg(":",$line)) { 
$lines = split(":",$line); 
$this->m_httphead[strtolower(trim($lines[0]))] = trim($lines[1]); 
} 
} 
} 
 
/** 
* 获得一个Http头的值 
*/ 
public function GetHead($headname) { 
$headname = strtolower($headname); 
if (isset($this->m_httphead[$headname])) { 
return $this->m_httphead[$headname]; 
} else { 
return ""; 
} 
} 
 
/**
* 打开连接
*/ 
public function PrivateOpenHost() { 
if ($this->m_host=="") return false; 
$this->m_fp = @fsockopen($this->m_host, $this->m_port, &$errno, &$errstr,10); 
if (!$this->m_fp){ 
$this->m_error = $errstr; 
return false; 
} else { 
return true; 
} 
} 
 
/**
* 关闭连接
*/ 
public function Close(){ 
@fclose($this->m_fp); 
} 
} 
 
#两种使用方法 
 
#打开网页 
$httpdown = new HttpDownload(); 
$httpdown->OpenUrl("http://www.google.com.hk"); 
echo $httpdown->GetHtml(); 
$httpdown->Close(); 

#下载文件 
$file = new HttpDownload(); # 实例化类 
$file->OpenUrl("/an/rust020/rust020.pdf"); # 远程文件地址 
$file->SaveToBin("rust020.pdf"); # 保存路径及文件名 
$file->Close(); # 释放资源 
?>