PHP 下载远程文件

PHP 下载远程文件类,支持断点续传下载，代码内含有具体的调用说明。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。

001<?php

002/**

003 * 下载远程文件类支持断点续传

004 */

005class HttpDownload {

006    private $m_url = "";

007    private $m_urlpath = "";

008    private $m_scheme = "http";

009    private $m_host = "";

010    private $m_port = "80";

011    private $m_user = "";

012    private $m_pass = "";

013    private $m_path = "/";

014    private $m_query = "";

015    private $m_fp = "";

016    private $m_error = "";

017    private $m_httphead = "" ;

018    private $m_html = "";

019  

020    /**

021     * 初始化

022     */

023    public function PrivateInit($url){

024        $urls = "";

025        $urls = @parse_url($url);

026        $this->m_url = $url;

027        if(is_array($urls)) {

028            $this->m_host = $urls["host"];

029            if(!empty($urls["scheme"])) $this->m_scheme = $urls["scheme"];

030            if(!empty($urls["user"])) $this->m_user = $urls["user"];

031            if(!empty($urls["pass"])) $this->m_pass = $urls["pass"];

032            if(!empty($urls["port"])) $this->m_port = $urls["port"];

033            if(!empty($urls["path"])) $this->m_path = $urls["path"];

034            $this->m_urlpath = $this->m_path;

035            if(!empty($urls["query"])) {

036                $this->m_query = $urls["query"];

037                $this->m_urlpath .= "?".$this->m_query;

038            }

039        }

040    }

041  

042    /**

043    * 打开指定网址

044    */

045    function OpenUrl($url) {

046        #重设各参数

047        $this->m_url = "";

048        $this->m_urlpath = "";

049        $this->m_scheme = "http";

050        $this->m_host = "";

051        $this->m_port = "80";

052        $this->m_user = "";

053        $this->m_pass = "";

054        $this->m_path = "/";

055        $this->m_query = "";

056        $this->m_error = "";

057        $this->m_httphead = "" ;

058        $this->m_html = "";

059        $this->Close();

060        #初始化系统

061        $this->PrivateInit($url);

062        $this->PrivateStartSession();

063    }

064 

065    /**

066    * 获得某操作错误的原因

067    */

068    public function printError() {

069        echo "错误信息：".$this->m_error;

070        echo "具体返回头：<br>";

071        foreach($this->m_httphead as $k=>$v) {

072            echo "$k => $v <br>\r\n";

073        }

074    }

075  

076    /**

077    * 判别用Get方法发送的头的应答结果是否正确

078    */

079    public function IsGetOK() {

080        if( ereg("^2",$this->GetHead("http-state")) ) {

081            return true;

082        } else {

083            $this->m_error .= $this->GetHead("http-state")." - ".$this->GetHead("http-describe")."<br>";

084            return false;

085        }

086    }

087     

088    /**

089    * 看看返回的网页是否是text类型

090    */

091    public function IsText() {

092        if (ereg("^2",$this->GetHead("http-state")) && eregi("^text",$this->GetHead("content-type"))) {

093            return true;

094        } else {

095            $this->m_error .= "内容为非文本类型<br>";

096            return false;

097        }

098    }

099    /**

100    * 判断返回的网页是否是特定的类型

101    */

102    public function IsContentType($ctype) {

103        if (ereg("^2",$this->GetHead("http-state")) && $this->GetHead("content-type") == strtolower($ctype)) {

104            return true;

105        } else {

106            $this->m_error .= "类型不对 ".$this->GetHead("content-type")."<br>";

107            return false;

108        }

109    }

110     

111    /**

112    * 用 HTTP 协议下载文件

113    */

114    public function SaveToBin($savefilename) {

115        if (!$this->IsGetOK()) return false;

116        if (@feof($this->m_fp)) {

117            $this->m_error = "连接已经关闭！";

118            return false;

119        }

120        $fp = fopen($savefilename,"w") or die("写入文件 $savefilename 失败！");

121        while (!feof($this->m_fp)) {

122            @fwrite($fp,fgets($this->m_fp,256));

123        }

124        @fclose($this->m_fp);

125        return true;

126    }

127     

128    /**

129    * 保存网页内容为 Text 文件

130    */

131    public function SaveToText($savefilename) {

132        if ($this->IsText()) {

133            $this->SaveBinFile($savefilename);

134        } else {

135            return "";

136        }

137    }

138     

139    /**

140    * 用 HTTP 协议获得一个网页的内容

141    */

142    public function GetHtml() {

143        if (!$this->IsText()) return "";

144        if ($this->m_html!="") return $this->m_html;

145        if (!$this->m_fp||@feof($this->m_fp)) return "";

146        while(!feof($this->m_fp)) {

147            $this->m_html .= fgets($this->m_fp,256);

148        }

149        @fclose($this->m_fp);

150        return $this->m_html;

151    }

152     

153    /**

154    * 开始 HTTP 会话

155    */

156    public function PrivateStartSession() {

157        if (!$this->PrivateOpenHost()) {

158            $this->m_error .= "打开远程主机出错!";

159            return false;

160        }

161        if ($this->GetHead("http-edition")=="HTTP/1.1") {

162            $httpv = "HTTP/1.1";

163        } else {

164            $httpv = "HTTP/1.0";

165        }

166        fputs($this->m_fp,"GET ".$this->m_urlpath." $httpv\r\n");

167        fputs($this->m_fp,"Host: ".$this->m_host."\r\n");

168        fputs($this->m_fp,"Accept: */*\r\n");

169        fputs($this->m_fp,"User-Agent: Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.2)\r\n");

170        #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

171        if ($httpv=="HTTP/1.1") {

172            fputs($this->m_fp,"Connection: Close\r\n\r\n");

173        } else {

174            fputs($this->m_fp,"\r\n");

175        }

176        $httpstas = fgets($this->m_fp,256);

177        $httpstas = split(" ",$httpstas);

178        $this->m_httphead["http-edition"] = trim($httpstas[0]);

179        $this->m_httphead["http-state"] = trim($httpstas[1]);

180        $this->m_httphead["http-describe"] = "";

181        for ($i=2;$i<count($httpstas);$i++) {

182            $this->m_httphead["http-describe"] .= " ".trim($httpstas[$i]);

183        }

184        while (!feof($this->m_fp)) {

185            $line = str_replace("\"","",trim(fgets($this->m_fp,256)));

186            if($line == "") break;

187            if (ereg(":",$line)) {

188                $lines = split(":",$line);

189                $this->m_httphead[strtolower(trim($lines[0]))] = trim($lines[1]);

190            }

191        }

192    }

193     

194    /**

195    * 获得一个Http头的值

196    */

197    public function GetHead($headname) {

198        $headname = strtolower($headname);

199        if (isset($this->m_httphead[$headname])) {

200            return $this->m_httphead[$headname];

201        } else {

202            return "";

203        }

204    }

205     

206    /**

207    * 打开连接

208    */

209    public function PrivateOpenHost() {

210        if ($this->m_host=="") return false;

211        $this->m_fp = @fsockopen($this->m_host, $this->m_port, &$errno, &$errstr,10);

212        if (!$this->m_fp){

213            $this->m_error = $errstr;

214            return false;

215        } else {

216            return true;

217        }

218    }

219     

220    /**

221    * 关闭连接

222    */

223    public function Close(){

224        @fclose($this->m_fp);

225    }

226}

227 

228#两种使用方法，分别如下：

229 

230#打开网页

231$httpdown = new HttpDownload();

232$httpdown->OpenUrl("http://www.google.com.hk");

233echo $httpdown->GetHtml();

234$httpdown->Close();

235 

236 

237#下载文件

238$file = new HttpDownload(); # 实例化类

239$file->OpenUrl("http://www.ti.com.cn/cn/lit/an/rust020/rust020.pdf"); # 远程文件地址

240$file->SaveToBin("rust020.pdf"); # 保存路径及文件名

241$file->Close(); # 释放资源

242?>