PHP 下載遠程文件類,支持斷點續傳下載，代碼內含有具體的調用說明。程序主要是使用 HTTP 協議下載文件，HTTP1.1協議必須指定文檔結束后關閉鏈接,否則讀取文檔時無法使用feof判斷結束，可以有兩種使用方法，具體請下載查看源碼。

<?php
/**


下載遠程文件類支持斷點續傳 
*/
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;
 }

}
}
/**

打開指定網址
*/
function OpenUrl($url) {
#重設各參數
$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();
#初始化系統
$this->PrivateInit($url);
$this->PrivateStartSession();
}

/**

獲得某操作錯誤的原因
*/
public function printError() {
echo "錯誤信息：".$this->m_error;
echo "具體返回頭：<br>";
foreach($this->m_httphead as $k=>$v) { 
   echo "$k => $v <br>\r\n"; 
}
}

/**

判別用Get方法發送的頭的應答結果是否正確
*/
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;
}
}

/**

看看返回的網頁是否是text類型
*/
public function IsText() {
if (ereg("^2",$this->GetHead("http-state")) && eregi("^text",$this->GetHead("content-type"))) { 
   return true; 
} else {
   $this->m_error .= "內容為非文本類型<br>";
   return false;
}
}
/**
判斷返回的網頁是否是特定的類型
*/
public function IsContentType($ctype) {
if (ereg("^2",$this->GetHead("http-state")) && $this->GetHead("content-type") == strtolower($ctype)) { 
   return true; 
} else {
   $this->m_error .= "類型不對 ".$this->GetHead("content-type")."<br>";
   return false;
}
}

/**

用 HTTP 協議下載文件
*/
public function SaveToBin($savefilename) {
if (!$this->IsGetOK()) return false;
if (@feof($this->m_fp)) { 
   $this->m_error = "連接已經關閉！"; 
   return false; 
}
$fp = fopen($savefilename,"w") or die("寫入文件 $savefilename 失敗！");
while (!feof($this->m_fp)) {
   @fwrite($fp,fgets($this->m_fp,256));
}
@fclose($this->m_fp);
return true;
}

/**

保存網頁內容為 Text 文件
*/
public function SaveToText($savefilename) {
if ($this->IsText()) {
   $this->SaveBinFile($savefilename);
} else {
   return "";
}
}

/**

用 HTTP 協議獲得一個網頁的內容
*/
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;
}

/**

開始 HTTP 會話
/
public function PrivateStartSession() {
if (!$this->PrivateOpenHost()) {
   $this->m_error .= "打開遠程主機出錯!";
   return false;
}
if ($this->GetHead("http-edition")=="HTTP/1.1") {
   $httpv = "HTTP/1.1";
} else {
   $httpv = "HTTP/1.0";
}
fputs($this->m_fp,"GET ".$this->m_urlpath." $httpv\r\n");
fputs($this->m_fp,"Host: ".$this->m_host."\r\n");
fputs($this->m_fp,"Accept: /*\r\n");
fputs($this->m_fp,"User-Agent: Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.2)\r\n");
#HTTP1.1協議必須指定文檔結束后關閉鏈接,否則讀取文檔時無法使用feof判斷結束
if ($httpv=="HTTP/1.1") {
   fputs($this->m_fp,"Connection: Close\r\n\r\n");
} else {
   fputs($this->m_fp,"\r\n");
}
$httpstas = fgets($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[$i]);
}
while (!feof($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]);

   }
}
}

/**

獲得一個Http頭的值
*/
public function GetHead($headname) {
$headname = strtolower($headname);
if (isset($this->m_httphead[$headname])) {
   return $this->m_httphead[$headname];
} else {
   return "";
}
}

/**

打開連接
*/
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;
}
}

/**

關閉連接
*/
public function Close(){
@fclose($this->m_fp);
}
}





兩種使用方法，分別如下：
打開網頁
$httpdown = new HttpDownload();
$httpdown->OpenUrl("
下載文件

$file = new HttpDownload(); # 實例化類
$file->OpenUrl("