ltrim
In response to using exec instead for performance (Nov 13 2007 post), It looks like the performance depends on the size of the file. See the results below using the same script from the original post. The first hash is with md5_file and the second is with openssl md5.
With a 1MB file:
Hash = df1555ec0c2d7fcad3a03770f9aa238a; time = 0.005006
Hash = df1555ec0c2d7fcad3a03770f9aa238a; time = 0.01498
With a 2MB file:
Hash = 4387904830a4245a8ab767e5937d722c; time = 0.010393
Hash = 4387904830a4245a8ab767e5937d722c; time = 0.016691
With a 10MB file:
Hash = b89f948e98f3a113dc13fdbd3bdb17ef; time = 0.241907
Hash = b89f948e98f3a113dc13fdbd3bdb17ef; time = 0.037597
Performance seems to change proportionally with the file size. Judging from the previous post's default file name (.mov) he/she was probably dealing with a large file. These are just quick tests and far from a perfect benchmark, but you might want to test your own files before assuming that the openssl solution is faster (ie, if working with small text files vs. movies, etc)
md5_file
(PHP 4 >= 4.2.0, PHP 5, PECL hash:1.1-1.3)
md5_file — Calcola l'hash md5 del file dato
Descrizione
string md5_file
( string $filename
[, bool $raw_output
] )
Calcola l'hash md5 del file filename utilizzando l' » RSA Data Security, Inc. MD5 Message-Digest Algorithm, e lo restituisce. L'hash prodotto è un numero esadecimale di 32 caratteri. Se il secondo parametro raw_output è impostato a TRUE, il valore md5 è restituito nel formato binario raw con una lunghezza di 16 caratteri.
Nota: Il parametro opzionale raw_output è stato aggiunto in PHP 5.0.0, e come default vale FALSE
Questa funzione ha il medesimo scopo dell'utilità di linea di comando md5sum.
Vedere anche md5(), crc32() e sha1_file().
add a note
User Contributed Notesmd5_file
smartin
12-Mar-2008 01:58
12-Mar-2008 01:58
toby at globaloptima dot co dot uk
18-Nov-2007 09:15
18-Nov-2007 09:15
I'm wondering about the MD5_DIR function posted by potsed, what happens if the file listing is returned in a different order?
From what I can tell you get different MD5's based on the order, a minor addition sorts this:
...
asort($filemd5s); //sort the md5s before concat
return md5(implode('', $filemd5s));
}
glau dot stuff at N0_SPAM dot ridiculousprods dot com
14-Nov-2007 02:54
14-Nov-2007 02:54
It's much faster to call an 'exec' command to openssl md5 than to use md5_file.
<?php
$file_path = '/path/to/large/video_file.mov';
$begin = microtime(true);
$hash = md5_file($file_path);
$end = microtime(true) - $begin;
echo "Hash = $hash; time = $end<br>";
# Hash = eac425a6f5b90f69e74710b015228640; time = 2.5333859920502
$begin = microtime(true);
$result = split('=',exec("openssl md5 $file_path"));
$end = microtime(true) - $begin;
echo "Hash = ".$result[1]."; time = $end";
#Hash = eac425a6f5b90f69e74710b015228640; time = 0.79528999328613
?>
I consistently see about a 3x improvement in speed.
potsed [at] gmail [dot] com
27-May-2007 01:12
27-May-2007 01:12
Heres a function to give an md5 for an entire directory..
function MD5_DIR($dir)
{
if (!is_dir($dir))
{
return false;
}
$filemd5s = array();
$d = dir($dir);
while (false !== ($entry = $d->read()))
{
if ($entry != '.' && $entry != '..')
{
if (is_dir($dir.'/'.$entry))
{
$filemd5s[] = MD5_DIR($dir.'/'.$entry);
}
else
{
$filemd5s[] = md5_file($dir.'/'.$entry);
}
}
}
$d->close();
return md5(implode('', $filemd5s));
}
bubba at revbubba dot com
29-Mar-2005 02:56
29-Mar-2005 02:56
a working example of the usage of this function, to confirm a specific file has not been modified (replace all instances of "myfile.xxx" with your filename):
<?php
$chkfilename = "myfile.xxx";
$chkmd5return = md5_file($chkfilename);
if ($chkmd5return != "myfile.xxx's md5 value") {
echo "You have replaced myfile.xxx with an unknown version of the file, please replace the original file.";
} else {
(your code to be executed, now that it has confirmed your myfile.xxx has been unmodified)
}
?>
To find out the file's md5 value, create a new .php doc, and put this code in it:
<?php
$chkfilename = "myfile.xxx";
$chkmd5return = md5_file($chkfilename);
echo $chkmd5return;
?>
Then upload the new .php doc to your webserver and navigate to it. Be sure to delete the new .php doc once you have plugged in the value it spits out, into the "myfile.xxx's md5 value" in the first example above.
I just thought this example might be helpful to someone somewhere... if you php.net people feel it needs editing or deletion, I leave it to your discretion. ;)
richard at interlink dot com dot au
16-Nov-2004 09:57
16-Nov-2004 09:57
For those of you with PHP 4 that want to output the "raw" 128 bit hash, all you need to do is send it to pack to convert the hex string into the raw output.
ie:
$filename="checkthisfile.bin";
$rawhash=pack("H*",md5_file($filename));