断点下载——php

<?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 = $urls["host"];                if(!empty($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 => $v <br>\r\n";            }        }              /**        * 判别用Get方法发送的头的应答结果是否正确        */        public function IsGetOK() {            if( preg_match('#^2#',$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 (preg_match('#^2#',$this->GetHead("http-state")) && preg_match('#^text#i',$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 (preg_match('#^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." $httpv\r\n");            fputs($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);            $httpstas = explode(' ',$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($line == "") break;                if (preg_match('#:#',$line)) {                    $lines = explode(':',$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.ti.com.cn/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 ?>

转载别人的。