Gravity forms & bitcoin address Validation WordPress

Bob answers:

Add this code in functions.php file of your theme.

It is not tested so not sure if it will work or not.

<strong>Note:</strong> In below code there is line <em>add_filter( 'gform_field_validation_6_1', 'validate_bitcoin_address', 10, 4 );</em>
you need to change 6 with your form id and 1 with your field id. Here 6 and 1 are place holder only.



function decodeBase58($input) {
$alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";

$out = array_fill(0, 25, 0);
for($i=0;$i<strlen($input);$i++){
if(($p=strpos($alphabet, $input[$i]))===false){
throw new \Exception("invalid character found");
}
$c = $p;
for ($j = 25; $j--; ) {
$c += (int)(58 * $out[$j]);
$out[$j] = (int)($c % 256);
$c /= 256;
$c = (int)$c;
}
if($c != 0){
throw new \Exception("address too long");
}
}

$result = "";
foreach($out as $val){
$result .= chr($val);
}

return $result;
}
function validate_bitcoin($address){
$decoded = decodeBase58($address);

$d1 = hash("sha256", substr($decoded,0,21), true);
$d2 = hash("sha256", $d1, true);

if(substr_compare($decoded, $d2, 21, 4)){
throw new \Exception("bad digest");
}
return true;
}

//The following declaration targets field 1 in form 6
add_filter( 'gform_field_validation_6_1', 'validate_bitcoin_address', 10, 4 );
function validate_bitcoin_address( $result, $value, $form, $field ){

if ( $result['is_valid'] ) {
$isvalid_bitcoin = validate_bitcoin( $value );
if($isvalid_bitcoin != true){
$result['is_valid'] = false;
$result['message'] = 'Please enter valid bitcoin no.';
}
}
return $result;
}


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