Topic: PHP Coding question in regards to validat user input before passing it into mysq (Read 351 times)

//Check if form submitted
if($_SERVER['REQUEST_METHOD'] == 'POST'){

     //Check if address valid and insert into db if so
     if(checkAddress($_POST['address'])){
          INSERT INTO DATABASE HERE AND REDIRECT OR DO WHATEVER ON SUCCESSFUL INSERT
     }
     //Display error for invalid address
     else{
          echo "Invalid address";
     }
}

//Display form if form not submitted
else{
     FORM HTML CODE HERE
}

if (checkAddress($address) {
   .... code address valid
} else {
   ... code address not valid
}

function checkAddress($address)
{
    $origbase58 = $address;
    $dec = "0";
 
    for ($i = 0; $i < strlen($address); $i++)
    {
        $dec = bcadd(bcmul($dec,"58",0),strpos("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz",substr($address,$i,1)),0);
    }
 
    $address = "";
 
    while (bccomp($dec,0) == 1)
    {
        $dv = bcdiv($dec,"16",0);
        $rem = (integer)bcmod($dec,"16");
        $dec = $dv;
        $address = $address.substr("0123456789ABCDEF",$rem,1);
    }
 
    $address = strrev($address);
 
    for ($i = 0; $i < strlen($origbase58) && substr($origbase58,$i,1) == "1"; $i++)
    {
        $address = "00".$address;
    }
 
    if (strlen($address)%2 != 0)
    {
        $address = "0".$address;
    }
 
    if (strlen($address) != 50)
    {
        return false;
    }
 
    if (hexdec(substr($address,0,2)) > 0)
    {
        return false;
    }
 
    return substr(strtoupper(hash("sha256",hash("sha256",pack("H*",substr($address,0,strlen($address)-8)),true))),0,8) == substr($address,strlen($address)-8);
}