php file upload and download source code

　　First, File upload

Front page:

<! DOCTYPE html>
　　Background processing:
<?php//receive information about the delivery of the submitted page $name = $_post[' username '); $intro = $_post[' Fileintro '];//$_files information about the file//echo "<pre >//Print_r ($_files);//echo "</pre>";//You can limit the file size here/* $filesize = $_files[' myfile ' [' Size '];if ($    filesize>2*1024*1024) {echo "file too large to upload"; Exit ();} *///can restrict the file type/* $filetype = $_files[' myfile ' [' type '];     if ($filetype! = ' image/jpg ' && $filetype! = ' application/pdf ') {echo "file type can be JPG and PDF only"; Exit (); }*/if (is_uploaded_file ($_files[' myfile ' [' tmp_name '])) {//dump the file to the directory you wish to store $uploaded = $_files[' myfile ' [' Tmp_name '        ]; Each user dynamically creates a folder $userpath = $_server[' Document_root '). "    /up/". $name;    Determine if the user already has a folder if (!file_exists ($userpath)) {mkdir ($userpath);    }//Prevent the same user from uploading a file with the same name, you can add a timestamp to the file. $moveto = $userpath. "        /". Time (). $_files[' myfile ' [' name '];    or modify the file name, but you need to use string processing to intercept the filename suffix $truename = $_files[' myfile ' [' name ']; $moveto = $userpath. "        /". Time (). substr ($truename, Strrpos ($truename,". ")); if (MoVe_uploaded_file ($uploaded, Iconv ("Utf-8", "gb2312", $moveto)) {echo "Upload file". $_files[' myfile ' [' Name ']. "    Success "; }else{echo "Upload file". $_files[' myfile ' [' Name ']. "    Failure "; }}else{echo "Upload file". $FILES [' myfile '] [' name ']. " Failed ";}? >
　　Second, the file download:
Single File Download:
 <?php function Down_file ($file _name, $file _path) {//$file _name = Iconv ("Uft-8", "gb2312", $file _name); If the file name is in Chinese, the Chinese name needs to be transcoded gb2312//The file to be downloaded reads into the server's memory//the server returns the file data to the browser//browser writes the file to the user-specified location//1. Determine if the file exists if (!file_exist        S ($file _name)) {echo "111";    return;    } $fp = fopen ($file _name, "R");    $file _size = filesize ($file _name);    Get file Size//can limit browser download file size via file_size.    Returns the header of the file ("Content-type:application/octet-stream");    Returns the header by byte size ("Accept-ranges:bytes");    Returns the file size header ("Accept-length: $file _size");    The Client Popup dialog box, corresponding to the filename header ("content-disposition:attachment;filename=". $file _name);      $buffer = 1024;    Define buffers//In order to download the security, it is best to use the file byte read counter $file _count = 0;    Feof is used to determine if a file is read to the end of the document while (!feof ($fp) && ($file _size-$file _count>0)) {$file _data = fread ($fp, $buffer);    Statistics read how many bytes $file _count+ $buffer;       echo $file _data;    Send some data to the browser} fclose ($FP); Close file}?> 
　　Multiple file Downloads:
downlist.php:
<a href= "downprocess.php?filename=1.jpg" >down</a> <br><br><a href= "downprocess.php?filename=2.jpg" >down</a><br><br><a href= "downprocess.php?filename=3.jpg" >down</a><br><br><a href=" Downprocess.php?filename=4.jpg ">down</ A><br><br>
　　downprocess.php:
<?php    $filename = $_request[' filename '];    function Down_file ($file _name) {    if (!file_exists ($file _name)) {        echo "111";        return;    }    $fp = fopen ($file _name, "R");    $file _size = filesize ($file _name);    Header ("Content-type:application/octet-stream");    Returns the header by byte size    ("accept-ranges:bytes");    Returns the file size    header ("Accept-length: $file _size");    The Client Popup dialog box, corresponding to the filename    header ("Content-disposition:attachment;filename=". $file _name);    $buffer = 1024x768;      Defines the buffer    $file _count = 0;    The feof is used to determine if a file is read to the end of the document    while (!feof ($fp) && ($file _size-$file _count>0)) {        $file _data = fread ($fp, $buffer);        Statistics read how many bytes        $file _count+ $buffer;        echo $file _data;           Send some data to the browser        }    fclose ($FP);    }    Down_file ($filename);? >
php file upload and download source code