Auto credit check?

Through PHP Post maybe?

[ahmedtheking]

Anyone know of a system that allows for a simple credit check when the details are passed through PHP?

[henry0]

I do not think you can even code anything without somehow partnering with one of the very few big guys
and it is going to be costly :)

[edited by: dreamcatcher at 9:06 am (utc) on May 13, 2007]
[edit reason] no urls as per T.O.S [webmasterworld.com].Thanks [/edit]

[FiRe]

<?php
/*==============================================================================

This routine checks the credit card number. The following checks are made:

1. A number has been provided
2. The number is a right length for the card
3. The number has an appropriate prefix for the card
4. The number has a valid modulus 10 number check digit if required

If the validation fails an error is reported.

The structure of credit card formats was gleaned from a variety of sources on
the web, although the best is probably on Wikepedia ("Credit card number"):

[en.wikipedia.org...]

Input parameters:
cardnumber number on the card
cardname name of card as defined in the card list below
Output parameters:
cardnumber number on the card
cardname name of card as defined in the card list below

Author: John Gardner
Date: 4th January 2005
Updated: 26th February 2005 additional credit cards added
1st July 2006 multiple definition of Discovery card removed
27th Nov. 2006 Additional cards added from Wikipedia

if (isset($_GET['submitted'])) {
if (checkCreditCard ($_GET['CardNumber'], $_GET['CardType'], $ccerror, $ccerrortext)) {
$ccerrortext = 'This card has a valid format';
}
}

==============================================================================*/

function checkCreditCard ($cardnumber, $cardname, &$errornumber, &$errortext) {

// Define the cards we support. You may add additional card types.

// Name: As in the selection box of the form - must be same as user's
// Length: List of possible valid lengths of the card number for the card
// prefixes: List of possible prefixes for the card
// checkdigit Boolean to say whether there is a check digit

// Don't forget - all but the last array definition needs a comma separator!

$cards = array ( array ('name' => 'American Express',
'length' => '15',
'prefixes' => '34,37',
'checkdigit' => true
),
array ('name' => 'Carte Blanche',
'length' => '14',
'prefixes' => '300,301,302,303,304,305,36,38',
'checkdigit' => true
),
array ('name' => 'Diners Club',
'length' => '14',
'prefixes' => '300,301,302,303,304,305,36,38',
'checkdigit' => true
),
array ('name' => 'Discover',
'length' => '16',
'prefixes' => '6011',
'checkdigit' => true
),
array ('name' => 'Enroute',
'length' => '15',
'prefixes' => '2014,2149',
'checkdigit' => true
),
array ('name' => 'JCB',
'length' => '15,16',
'prefixes' => '3,1800,2131',
'checkdigit' => true
),
array ('name' => 'Maestro',
'length' => '16',
'prefixes' => '5020,6',
'checkdigit' => true
),
array ('name' => 'MasterCard',
'length' => '16',
'prefixes' => '51,52,53,54,55',
'checkdigit' => true
),
array ('name' => 'Solo',
'length' => '16,18,19',
'prefixes' => '6334, 6767',
'checkdigit' => true
),
array ('name' => 'Switch',
'length' => '16,18,19',
'prefixes' => '4903,4905,4911,4936,564182,633110,6333,6759',
'checkdigit' => true
),
array ('name' => 'Visa',
'length' => '13,16',
'prefixes' => '4',
'checkdigit' => true
),
array ('name' => 'Visa Electron',
'length' => '16',
'prefixes' => '417500,4917,4913',
'checkdigit' => true
)
);

$ccErrorNo = 0;

$ccErrors [0] = "Unknown card type";
$ccErrors [1] = "No card number provided";
$ccErrors [2] = "Credit card number has invalid format";
$ccErrors [3] = "Credit card number is invalid";
$ccErrors [4] = "Credit card number is wrong length";

// Establish card type
$cardType = -1;
for ($i=0; $i<sizeof($cards); $i++) {

// See if it is this card (ignoring the case of the string)
if (strtolower($cardname) == strtolower($cards[$i]['name'])) {
$cardType = $i;
break;
}
}

// If card type not found, report an error
if ($cardType == -1) {
$errornumber = 0;
$errortext = $ccErrors [$errornumber];
return false;
}

// Ensure that the user has provided a credit card number
if (strlen($cardnumber) == 0) {
$errornumber = 1;
$errortext = $ccErrors [$errornumber];
return false;
}

// Remove any spaces from the credit card number
$cardNo = str_replace (' ', '', $cardnumber);

// Check that the number is numeric and of the right sort of length.
if (!eregi('^[0-9]{13,19}$',$cardNo)) {
$errornumber = 2;
$errortext = $ccErrors [$errornumber];
return false;
}

// Now check the modulus 10 check digit - if required
if ($cards[$cardType]['checkdigit']) {
$checksum = 0; // running checksum total
$mychar = ""; // next char to process
$j = 1; // takes value of 1 or 2

// Process each digit one by one starting at the right
for ($i = strlen($cardNo) - 1; $i >= 0; $i--) {

// Extract the next digit and multiply by 1 or 2 on alternative digits.
$calc = $cardNo{$i} * $j;

// If the result is in two digits add 1 to the checksum total
if ($calc > 9) {
$checksum = $checksum + 1;
$calc = $calc - 10;
}

// Add the units element to the checksum total
$checksum = $checksum + $calc;

// Switch the value of j
if ($j ==1) {$j = 2;} else {$j = 1;};
}

// All done - if checksum is divisible by 10, it is a valid modulus 10.
// If not, report an error.
if ($checksum % 10!= 0) {
$errornumber = 3;
$errortext = $ccErrors [$errornumber];
return false;
}
}

// The following are the card-specific checks we undertake.

// Load an array with the valid prefixes for this card
$prefix = split(',',$cards[$cardType]['prefixes']);

// Now see if any of them match what we have in the card number
$PrefixValid = false;
for ($i=0; $i<sizeof($prefix); $i++) {
$exp = '^' . $prefix[$i];
if (ereg($exp,$cardNo)) {
$PrefixValid = true;
break;
}
}

// If it isn't a valid prefix there's no point at looking at the length
if (!$PrefixValid) {
$errornumber = 3;
$errortext = $ccErrors [$errornumber];
return false;
}

// See if the length is valid for this card
$LengthValid = false;
$lengths = split(',',$cards[$cardType]['length']);
for ($j=0; $j<sizeof($lengths); $j++) {
if (strlen($cardNo) == $lengths[$j]) {
$LengthValid = true;
break;
}
}

// See if all is OK by seeing if the length was valid.
if (!$LengthValid) {
$errornumber = 4;
$errortext = $ccErrors [$errornumber];
return false;
};

// The credit card is in the required format.
return true;
}
/*============================================================================*/
?>

[ahmedtheking]

Very nice!

[henry0]

ahmed,
as far as I can read this is a credit card number validation process.

You asked for "check credit" which leads to understanding:
checking credit history :(

[ahmedtheking]

No I understand what you mean. You're right. In order to do a full credit check it needs to be done manually. It's a bit of pain, but what I've found is that companies such as Protx offer a 'real' validation service where it can check your billing details against your card details and return a 'credit limit' if you have a credit card!

[henry0]

Interesting, thanks