用php写的一个HTTP下载类

在php中，下载http资源比较常用的一种做法就是用 file_get_contents 这个函数，但这函数无法获得http头的信息，会给一些应用带来不方便，因此我写了一个http下载类来解决这个问题，测试感觉速度和file_get_contents相差无几。

<?
/*=======================================
// 织梦Http下载类
// 织梦之旅
=======================================*/
class DedeHttpDown
{
 var $m_url = "";
 var $m_urlpath = "";
 var $m_scheme = "http";
 var $m_host = "";
 var $m_port = "80";
 var $m_user = "";
 var $m_pass = "";
 var $m_path = "/";
 var $m_query = "";
 var $m_fp = "";
 var $m_error = "";
 var $m_httphead = "" ;
 var $m_html = "";
 //


 //初始化系统


 //


 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


 //


 function printError()
 {
  echo "错误信息：".$this->m_error;
  echo "具体返回头：
";
  foreach($this->m_httphead as $k=>$v)
  { echo "$k => $v
\r\n"; }
 }
 //


 //判别用Get方法发送的头的应答结果是否正确


 //


 function IsGetOK()
 {
  if( ereg("^2",$this->GetHead("http-state")) )
  { return true; }
  else
  {
   $this->m_error .= $this->GetHead("http-state")." - ".$this->GetHead("http-describe")."
";
   return false;
  }
 }
 //


 //看看返回的网页是否是text类型


 //


 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
";
   return false;
  }
 }
 //


 //判断返回的网页是否是特定的类型


 //


 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")."
";
   return false;
  }
 }
 //


 //用Http协议下载文件


 //


 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


 //


 function SaveToText($savefilename)
 {
  if($this->IsText()) $this->SaveBinFile($savefilename);
  else return "";
 }
 //


 //用Http协议获得一个网页的内容


 //


 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


 //


 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." $httpv\r\n");
  fputs($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: 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]);
   }
  }
 }
 //


 //获得一个Http头的值


 //


 function GetHead($headname)
 {
  $headname = strtolower($headname);
  if(isset($this->m_httphead[$headname]))
   return $this->m_httphead[$headname];
  else
   return "";
 }
 //


 //打开连接


 //


 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
 function Close(){
  @fclose($this->m_fp);
 }
}
?>

<?php

//这个类的使用方法：
//下载网页


$httpdown = new DedeHttpDown();
$httpdown->OpenUrl("http://");
echo $httpdown->GetHtml();
$httpdown->Close();
?>

<?php

//如果下载图片并保存,可以用
$httpdown = new DedeHttpDown();
$httpdown->OpenUrl("");
echo $httpdown->SaveBin("test.jpg");
$httpdown->Close();
echo "";
?>