PHP download remote file class that supports breakpoint resume download

PHP download remote file class, supports breakpoint resume download, and the code contains specific calling instructions. The program mainly uses the HTTP protocol to download files. The HTTP1.1 protocol must specify that the link should be closed after the document ends. Otherwise, feof cannot be used to judge the end when reading the document. There are two ways to use it. Please download and view the source code for details.

/**
 * Downloading remote files supports breakpoint resumption
*/
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 = "";

    /**
 * Initialization
*/
    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;
            }
        }
    }

    /**
 *Open the specified URL
*/
    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();
    }

    /**
 * Get the reason for an operation error
*/
    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";
        }
    }

    /**
 * Determine whether the response result of the header sent using the Get method is correct
*/
    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;
        }
    }

    /**
 * Check whether the returned web page is of text type
*/
    public function IsText() {
        if (ereg("^2",$this->GetHead("http-state")) && eregi("^text",$this->GetHead("content-type"))) {
            return true;
        } else {
            $this->m_error .= "内容为非文本类型";
            return false;
        }
    }
    /**
 * Determine whether the returned web page is of a specific type
*/
    public function IsContentType($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;
        }
    }

    /**
 * Download files using HTTP protocol
*/
    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;
    }

    /**
 * Save web content as Text file
*/
    public function SaveToText($savefilename) {
        if ($this->IsText()) {
            $this->SaveBinFile($savefilename);
        } else {
            return "";
        }
    }

    /**
 * Use HTTP protocol to obtain the content of a web page
*/
    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;
    }

    /**
 * Start HTTP session
*/
    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            $this->m_httphead["http-describe"] .= " ".trim($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]);
            }
        }
    }

    /**
 * Get the value of an HTTP header
*/
    public function GetHead($headname) {
        $headname = strtolower($headname);
        if (isset($this->m_httphead[$headname])) {
            return $this->m_httphead[$headname];
        } else {
            return "";
        }
    }

    /**
 * Open connection
*/
    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;
        }
    }

    /**
 * Close connection
*/
    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
?>

断点续传, PHP