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Digg  sha1_file
Calculate the sha1 hash of a file
(PHP 4 >= 4.3.0, PHP 5, PECL hash:1.1-1.3)
Code Examples / Notes » sha1_filegubatron
P2P programs like LimeWire utilize sha1 to identify files. However they do it in base32. Here's an utility class if you want to write a Gnutella client in PHP5 /** Utility base32 SHA1 class for PHP5 Copyright (C) 2006 Karl Magdsick (original author for Python) Angel Leon (ported to PHP5) Lime Wire LLC This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ class SHA1 { static $BASE32_ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'; /** Given a file it creates a magnetmix */ static function fileSHA1($file) { $raw = sha1_file($file,true); return SHA1::base32encode($raw); } //fileSHA1 /** Takes raw input and converts it to base32 */ static function base32encode($input) { $output = ''; $position = 0; $storedData = 0; $storedBitCount = 0; $index = 0; while ($index < strlen($input)) { $storedData <<= 8; $storedData += ord($input[$index]); $storedBitCount += 8; $index += 1; //take as much data as possible out of storedData while ($storedBitCount >= 5) { $storedBitCount -= 5; $output .= SHA1::$BASE32_ALPHABET[$storedData >> $storedBitCount]; $storedData &= ((1 << $storedBitCount) - 1); } } //while //deal with leftover data if ($storedBitCount > 0) { $storedData <<= (5-$storedBitCount); $output .= SHA1::$BASE32_ALPHABET[$storedData]; } return $output; } //base32encode } schiros
If you've got a script that allows user file upload, and you want to prevent multiple uploads of the same file: <? session_start(); $isDuplicate = false; if(isset($_FILES["filename"]["tmp_name"]) && file_exists($_FILES["filename"]["tmp_name"])) { $fileHash = sha1_file($_FILES["filename"]["tmp_name"]); if(!isset($_SESSION["check_filelist"])) { $_SESSION["check_filelist"] = array($fileHash); } elseif(in_array($fileHash,$_SESSION["check_filelist"])) { $isDuplicate = true; } else { $_SESSION["check_filelist"][] = $fileHash; } if($isDuplicate) { echo "You've already uploaded that file"; } else{ // do some stuff } } ?> admin
checking the sha1 of the file. ideal for download scripts making sure the file the user is downloading is not currupt by checking the sha1 key <?php $filename = './Path/To/Your/File.zip'; if (file_exists($filename)) { echo"i see the file"; } else { echo "recheck the link file maybe broken"; } $file = sha1_file('./Path/To/Your/File.zip'); echo" is file hash valid?"; echo"hash = add the hash here "; echo"hash of file :"; print($file); ?> |
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