PHP下载远程文件类源码，带详细注释，还支持断点续传-php教程

网站经常要用到下载远程图片的功能,有时还要下载.doc文档,所以就用php开发了一个下载远程文件的类,这个类支持断点续传下载,源代码中有具体的注释及使用说明案例.

程序主要是使用 HTTP 协议下载文件,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,可以有两种使用方法,具体请下载查看源码,代码如下:

<?php
/**
* 下载远程文件类支持断点续传
*/
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 = $urls["host"];
if(!emptyempty($urls["scheme"])) $this->m_scheme = $urls["scheme"];
if(!emptyempty($urls["user"])) $this->m_user = $urls["user"];
if(!emptyempty($urls["pass"])) $this->m_pass = $urls["pass"];
if(!emptyempty($urls["port"])) $this->m_port = $urls["port"];
if(!emptyempty($urls["path"])) $this->m_path = $urls["path"];
$this->m_urlpath = $this->m_path;
if(!emptyempty($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： ";
foreach($this->m_httphead as $k=>$v) {
echo "$k => $v rn";
}
}
/**
* 判别用Get方法发送的头的应答结果是否正确
*/
public function IsGetOK() {
if( ereg("^2",$this->GetHead("http-state")) ) {
return true;
} else {
$this->m_error .= $this->GetHead("http-state")." - ".$this->GetHead("http-describe")." ";
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 {
$this->m_error .= "内容为非文本类型 ";
return false;
}
}
/**
* 判断返回的网页是否是特定的类型
*/
public function IsContentType($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")." ";
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[$i]);
}
while (!feof($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，分别如下：
#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("http://www.phpfensi.com/cn/lit/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
?>

PHP下载远程文件类源码，带详细注释，还支持断点续传

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