[wp-trac] [WordPress Trac] #16925: Move the WP_Filesystem_SSH2 class to a plugin

[WordPress Trac]

#16925: Move the WP_Filesystem_SSH2 class to a plugin
--------------------------+-----------------------------
 Reporter:  dd32          |       Owner:  dd32
     Type:  defect (bug)  |      Status:  accepted
 Priority:  normal        |   Milestone:  Future Release
Component:  Filesystem    |     Version:
 Severity:  normal        |  Resolution:
 Keywords:  needs-patch   |
--------------------------+-----------------------------

Comment (by knuthmorris):

 Oh - and let's try phpseclib without either gmp or bcmath.  Doing so will
 require a slight modification to urdd's script:

 {{{
 <?php
 include('Net/SFTP.php');
 define('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_INTERNAL);
 $sftp = new Net_SFTP('www.domain.tld', 22);
 $sftp->login('user', 'pass');
 $start = microtime(true);
 $sftp->put('test', str_repeat('a', 256 * 1024));
 $elapsed = microtime(true) - $start;
 echo "took $elapsed seconds\r\n";


 $connection = ssh2_connect('www.domain.tld', 22);
 ssh2_auth_password($connection, 'user', 'pass');
 $sftp = ssh2_sftp($connection);
 $start = microtime(true);
 $stream = fopen("ssh2.sftp://$sftp/home/user/test", 'w');
 fputs($stream, str_repeat('a', 256 * 1024));
 fclose($stream);
 $elapsed = microtime(true) - $start;
 echo "took $elapsed seconds\r\n";
 ?>
 }}}

 See the define('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_INTERNAL)?
 That's new.  And here's what we get with that:

 {{{
 Trial #1:
 took 6.8606338500977 seconds
 took 7.5764989852905 seconds

 Trial #2:
 took 5.2222318649292 seconds
 took 7.167053937912 seconds

 Trial #3:
 took 5.325345993042 seconds
 took 7.7823340892792 seconds
 }}}
 Oh snap.  phpseclib owns again.

 Let's try it without mcrypt or gmp or bcmath.  I ensure that mcrypt is not
 used by doing define('CRYPT_RC4_MODE', CRYPT_RC4_MODE_INTERNAL).  Pure-PHP
 for everything.

 {{{
 Trial #1:
 took 5.2221701145172 seconds
 took 7.4742610454559 seconds

 Trial #2:
 took 5.2241580486298 seconds
 took 7.8221480846405 seconds

 Trial #3:
 took 5.2212400436401 seconds
 took 7.8840770721436 seconds
 }}}
 phpseclib wins again.

 But just in case you believe I'm cooking the books and you're too lazy to
 verify the results for yourself, here's proof that the bottleneck is how
 the network packets are handled.

 {{{
 <?php
 include('Crypt/RC4.php');
 include('Crypt/Random.php');

 define('CRYPT_RC4_MODE', CRYPT_RC4_MODE_INTERNAL);

 $rc4 = new Crypt_RC4();

 $key = '';
 for ($i = 0; $i < 16; $i++) {
     $key.= pack('n', crypt_random(0, 0xFFFF));
 }

 $rc4->setKey($key);
 $start = microtime(true);
 $rc4->encrypt(str_repeat("\0", 1536));
 $rc4->encrypt(str_repeat('a', 1024 * 1024));
 $elapsed = microtime(true) - $start;
 echo "took $elapsed seconds\r\n";
 }}}

 phpseclib uses arcfour256 by default hence my using Crypt_RC4 as well.
 str_repeat("\0", 1536) is encrypted because that's apparently what
 arcfour256 requires, per the source code comments in phpseclib.  Also,
 note how we're encrypting 1MB instead of the 256KB that we're uploading
 via SFTP.  And here are the times using phpseclib's pure-PHP RC4
 implementation:

 {{{
 Trial #1:
 took 2.6884229183197 seconds

 Trial #2:
 took 2.76646900177 seconds

 Trial #3:
 took 2.8742060661316 seconds
 }}}
 So, basically, it takes less time to encrypt 1MB then it takes to upload
 256KB.  The bottleneck in SFTP isn't solved by simply using C instead of
 PHP and phpseclib IS faster.

 Don't believe me?  Try it for yourself.  I'm not included the source code
 to make my post bigger.  I'm including it so you can verify my results
 instead of pulling random - and false - factoids out of thin air.

-- 
Ticket URL: <http://core.trac.wordpress.org/ticket/16925#comment:8>
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