PHP下载远程文件类源码，带详细注释，还支持断点续传

2024-09-04 11:45:10

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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.Vevb.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

?>