CODEWITHSUNDEEP
phppythonmysqlbinaryhex
igs013
igs013

Reputation: 1420

How does python converts mysql binary(16)

I have two apps one written in php and one in python and both of them use the same mysql database.

For the public id of the entries in some of the tables I use binary(16) fields(I can't change this, it must remain this way).

The question is how does python does the conversion of this binary field?

Let's take one of the entries as an example.

When I get it in php(from the db) the value of the public id is °•WiCÄ‘õ0Iò|–g, the same value is shown in SequelPro. But php myAdmin does a hex function over binary fields and shows 0bb09557691443c491f53049f27c9667. Now I managed in php to convert the binary to the value showed in php myAdmin and it works for all the entries but I've just noticed that python does another conversion. When I get the entry used in this example via python the public id is owwweye1rjnvt3i1d0ib18x3.

What I need to achieve is to convert in php what I get from MySql: °•WiCÄ‘õ0Iò|–g to what python sees: owwweye1rjnvt3i1d0ib18x3. The php app makes calls on the python one(not developed by me) and thus the id needs to be in the same format for a successfull call.

Any suggestions are welcomed. Thanks.

EDIT: If i send °•WiCÄ‘õ0Iò|–g from php to python and print it rigth away I get: °•WiCÄ‘õ0Iò|–g

Upvotes: 1

Views: 159

Answers (1)

igs013
igs013

Reputation: 1420

Finally I've sorted this out.

Seems that python converts to base36 not hex as I've wrongly supposed.

I've tried to simply base_convert 0bb09557691443c491f53049f27c9667 from 16 to 36 but I've got owwweye1rk04k4cskkw4s08s. Not really what I needed but still a great step further as it started to look like owwweye1rjnvt3i1d0ib18x3.

This difference I supposed to appear because of the large values to be converted(loss of precision), so I've further researched and found the bellow function, written by Clifford dot ct at gmail dot com on the php.net website:

<?php 

function str_baseconvert($str, $frombase=10, $tobase=36) { 
    $str = trim($str); 
    if (intval($frombase) != 10) { 
        $len = strlen($str); 
        $q = 0; 
        for ($i=0; $i<$len; $i++) { 
            $r = base_convert($str[$i], $frombase, 10); 
            $q = bcadd(bcmul($q, $frombase), $r); 
        } 
    } 
    else $q = $str; 

    if (intval($tobase) != 10) { 
        $s = ''; 
        while (bccomp($q, '0', 0) > 0) { 
            $r = intval(bcmod($q, $tobase)); 
            $s = base_convert($r, 10, $tobase) . $s; 
            $q = bcdiv($q, $tobase, 0); 
        } 
    } 
    else $s = $q; 

    return $s; 
} 

?>

I don't think others will come across this issue very often, but still if it happens hope they'll find this instead of burning their brains out like I did :))))

Upvotes: 1

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