sha1_file

(PHP 4 >= 4.3.0, PHP 5)

sha1_fileCalcula el hash sha1 de un archivo

Descripción

string sha1_file ( string $filename [, bool $raw_output = false ] )

Calcula el hash sha1 del archivo especificado mediante filename utilizando el » algoritmo de hash seguro 1 de US y devuelve ese hash. El hash es un número hexadecimal de 40 caracteres.

Parámetros

filename

El nombre del archivo para el hash.

raw_output

Cuando es TRUE, devuelve el resumen en formato binario sin tratar con una longitud de 20.

Valores devueltos

Devuelve un string cuando es exitoso o FALSE si no es así.

Ejemplos

Ejemplo #1 Ejemplo de sha1_file()

<?php
foreach(glob('/home/Kalle/myproject/*.php') as $ent)
{
    if(
is_dir($ent))
    {
        continue;
    }

    echo 
$ent ' (SHA1: ' sha1_file($ent) . ')'PHP_EOL;
}
?>

Historial de cambios

Versión Descripción
5.1.0 Cambiada la función para utilizar el API de flujo de datos. Esto significa que se puede utilizar con envolturas, como en sha1_file('http://ejemplo.com/..')
5.0.0 Agregado el parámetro raw_output.

Ver también

  • sha1() - Calcula el hash sha1 de un string
  • md5_file() - Calcula el resumen criptográfico md5 de un archivo dado
  • crc32() - Calcula el polinomio crc32 de una cadena

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User Contributed Notes 5 notes

up
7
xijque at gmail dot com
2 years ago
Just for the record -

As some have pointed out, you have two ways to generate the hash of a file:
Method 1 [this function]: sha1_file($file)
Method 2: sha1(file_get_contents($file))

It's important to realize that these two methods are NOT the same thing. If they were, I seriously doubt this function would exist.

The key difference, as far as I can tell, is how the file's contents are loaded. The second method loads the entirety of $file into memory before passing it to sha1($str). Method two, however, loads the contents of $file as they are needed to create the hash.

If you can guarantee that you'll only ever have to hash relatively small files, this difference means very little. If you have larger ones, though, loading the entirety of file into memory is a bad idea: best case, you slow down your server as it tries to handle the request; worse case, you run out of memory and don't get your hash at all.

Just try to keep this in mind if you decide to load the file's contents yourself, in lieu of using this function. On my system, I was able to use this function to generate the hash of a 2.6GB file in 22 seconds, whereas I could not with the second method, due to an out-of-memory error (which took 185 seconds).
up
1
admin at cmsrevolution dot com
7 years ago
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
"<br>is file hash valid?";
echo
"hash = add the hash here<br>";
echo
"hash of file :";
print(
$file);
?>
up
2
vista_ at live dot se
5 years ago
<?php
    
if(!function_exists('sha1_file'))
     {
          function
sha1_file($file = null)
          {
               if(
is_null($file) || !file_exists($file))
               {
                    return
trigger_error('File is null or does not exists');
               }

               return
sha1(file_get_contents($file));
          }
     }
?>

Remember, it's important to write a corret url like this:
/home/snackzon/public_html/php/sha1.php
up
0
schiros at invisihosting dot com
6 years ago
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   
           
}
        }
       
   
?>
up
-1
gubatron at gmail dot com
8 years ago
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

}
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