Similar to this question I wish to generate an htpasswd file entry from PHP. However it must be the APR1 (Apache) style, as pointed out within the original answer (The solution didn't show how you can implement the APR1 style), to utilize mod_dav_svn.

I can not appear to locate a working implementation and build the password.

I discovered this (I forget where now):

function crypt_apr1_md5($plainpasswd) {
    $salt = substr(str_shuffle("abcdefghijklmnopqrstuvwxyz0123456789"), 0, 8);
    $len = strlen($plainpasswd);
    $text = $plainpasswd.'$apr1$'.$salt;
    $bin = pack("H32", md5($plainpasswd.$salt.$plainpasswd));
    for($i = $len; $i > 0; $i -= 16) { $text .= substr($bin, 0, min(16, $i)); }
    for($i = $len; $i > 0; $i >>= 1) { $text .= ($i & 1) ? chr(0) : $plainpasswd{0}; }
    $bin = pack("H32", md5($text));
    for($i = 0; $i < 1000; $i++) {
        $new = ($i & 1) ? $plainpasswd : $bin;
        if ($i % 3) $new .= $salt;
        if ($i % 7) $new .= $plainpasswd;
        $new .= ($i & 1) ? $bin : $plainpasswd;
        $bin = pack("H32", md5($new));
    }
    for ($i = 0; $i < 5; $i++) {
        $k = $i + 6;
        $j = $i + 12;
        if ($j == 16) $j = 5;
        $tmp = $bin[$i].$bin[$k].$bin[$j].$tmp;
    }
    $tmp = chr(0).chr(0).$bin[11].$tmp;
    $tmp = strtr(strrev(substr(base64_encode($tmp), 2)),
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
    "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz");
    return "$"."apr1"."$".$salt."$".$tmp;
}

However it does not produce a working password. I believe this can be something related to the version of apache but am unsure. (I'm running on CENTOS 5)

Search for existing components which do it on sites like phpclasses.org. An example: http://www.phpclasses.org/browse/package/5066.html.

It works out I designed a mistake which function does actually create working APR1 htpasswd records. They are doing look dissimilar to those Apache produces however they will work.

This can be a little hacky, but have you thought about while using professional() function to call the command that creates the htpasswd ?

Thanks you! It really works like no bodies business.

Only a small comment: The salt may also contain "./" and "A..Z" besides "a..z0..9", so it's exactly the same string because the 'translate-to' string within the last line. And often you need to set the salt additionally, to produce reproducable results, like:

function crypt_apr1_md5( $plainpasswd, $salt = '' ) {
$translateTo = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
if ( $salt == '' ) { $salt = substr(str_shuffle($translateTo), 0, 8); }

...

$tmp = strtr(strrev(substr(base64_encode($tmp), 2)), "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/", $translateTo);
return '$apr1$'.$salt.'$'.$tmp;
}