Code sharing for php download files

This article introduces some methods and codes for downloading files in PHP, including system function calls, wget, and socket connection methods to download files, etc. Please use it as a reference for friends in need.

To download files in php, most of the methods are as follows: One is to use existing functions such as system and exec to call the download tool that comes with the system, such as wget to download files. The other is to use PHP itself to use Socket to download files.

The author likes to use the second method.

Use Socket to download files. If it is a file with http protocol, you must understand the running process of HTTP protocol. If it is FTP protocol, you must understand the running process of ftp protocol. For example, HTTP protocol accesses a file:

<?php
$fp = fsockopen("www.example.com", 80, $errno, $errstr, 30);
if (!$fp) {
        echo "$errstr ($errno)<br />\n";
} else {
    $out = "GET / HTTP/1.1\r\n";
    $out .= "Host: www.example.com\r\n";
    $out .= "Connection: Close\r\n\r\n";

    fwrite($fp, $out);
        while (!feof($fp)) {
            echo fgets($fp, 128);
        }
    fclose($fp);
}
?>

Use fopen to directly access remote files to achieve the purpose. At the same time, you can access http and ftp. Of course, if you follow the above idea, you can also use the ftp function library to achieve it.

Example of using fopen function:

#! /usr/bin/php
<?php
error_reporting(0);
set_time_limit(0);

//无参数则给出提示
if ($argc < 2){
  echo "Usage: ". $argv[0] ." URL [Destination]\n\n";
  exit();
}

//设置获取基本变量
$url = $argv[1];
$save_path = $argv[2] ? $argv[2] : "./";
$file_name = array_pop(explode("/", $url));
$localfile = $save_path . $file_name;

//检查变量
if (!check_url($url)){
   exit("Error: URL ". $url ." invalid.\n\n");
}
if (file_exists($localfile)){
   exit("Error: local file ". $localfile ." exists.\n\n");
}

//打开远程文件
$fp = fopen($url, "rb");
if (!$fp){
   exit("Error: Download ". $url ." failed.\n\n");
}

//打开本地文件
$sp = fopen($localfile, "wb");
if (!$sp){
   exit("Error: Open local file ". $localfile ." failed.\n\n");
}

//下载远程文件
echo "Downloading, please waiting...\n\n";
while (!feof($fp)){
    $tmpfile .= fread($fp, 1024);
}

//保存文件到本地
fwrite($sp, $tmpfile);
fclose($fp);
fclose($sp);
echo "Download file ". $file_name ." succeed!\n\n";

/* 检查URL合法性函数 */
function check_url($url){
   return preg_match("/^(http|ftp)(:\/\/)([a-zA-Z0-9-_]+[\.\/]+[\w\-_\/]+.*)+$/i", $url);    
}
?>

The above code is saved as a download.php file with the executable attribute: chmod +x download.php

Execute, pay attention to the correct path of the script: #!/usr/local/php/bin/php

Use the above script to download the file: download.php remote file saving path

If you download the Google Talk program to our /tmp directory: download.php http://dl.google.com/googletalk/googletalk-setup.exe /tmp/

If nothing goes wrong, wait for a while and you will see the googletalk-setup.exe file in the /tmp/ directory.

Here is a stronger HTTP download class:

<?
/*=================
// 织梦Http下载类
=======================*/
class DedeHttpDown
{
var $m_url = "";
var $m_urlpath = "";
var $m_scheme = "http";
var $m_host = "";
var $m_port = "80";
var $m_user = "";
var $m_pass = "";
var $m_path = "/";
var $m_query = "";
var $m_fp = "";
var $m_error = "";
var $m_httphead = "" ;
var $m_html = "";
//
//初始化系统
//
function PrivateInit($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);
     $this->PrivateStartSession();
}
//
//获得某操作错误的原因
//
function printError()
{
     echo "错误信息：".$this->m_error;
     echo "具体返回头：<br>";
     foreach($this->m_httphead as $k=>$v)
     { echo "$k => $v <br>\r\n"; }
}
//
//判别用Get方法发送的头的应答结果是否正确
//
function IsGetOK()
{
     if( ereg("^2",$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
//
function IsText()
{
     if(ereg("^2",$this->GetHead("http-state"))
      && eregi("^text",$this->GetHead("content-type")))
     { return true; }
     else
     {
      $this->m_error .= "内容为非文本类型<br>";
      return false;
     }
}
//
//判断返回的网页是否是特定的类型
//
function IsContentType($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")."<br>";
      return false;
     }
}
//
//用Http协议下载文件
//
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($this->m_fp);
     return true;
}
//
//保存网页内容为Text文件
//
function SaveToText($savefilename)
{
     if($this->IsText()) $this->SaveBinFile($savefilename);
     else return "";
}
//
//用Http协议获得一个网页的内容
//
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 $this->m_html;
}
//
//开始HTTP会话
//
function PrivateStartSession()
{
     if(!$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);
     $httpstas = split(" ",$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($lines[1]);
      }
     }
}
//
//获得一个Http头的值
//
function GetHead($headname)
{
     $headname = strtolower($headname);
     if(isset($this->m_httphead[$headname]))
      return $this->m_httphead[$headname];
     else
      return "";
}
//
//打开连接
//
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 = $errstr;
      return false;
     }
     else{
      return true;
     }
}
//
//关闭连接
//
function Close(){
     @fclose($this->m_fp);
}
}
?>

Call example: 1. Download the web page

<?
$httpdown = new DedeHttpDown();
$httpdown->OpenUrl("http://bbs.it-home.org");
echo $httpdown->GetHtml();
$httpdown->Close();
?>

2. Download the picture and save it

<?
$httpdown = new DedeHttpDown();
$httpdown->OpenUrl("http://img.jbxue.com/images/1.jpg");
echo $httpdown->SaveBin("test.jpg");
$httpdown->Close();
echo "<img  src='test.jpg' alt="Code sharing for php download files" >";
?>