Vouchers Lib

A PHP library for generating and validating vouchers. We make no assumptions about storage and instead offer the concept of Bags which can take any number of Vouchers. These bags can validate vouchers, generate new vouchers and apply validation rules across the whole set.

Install

composer require alancole/vouchers

Example

$model = new Vouchers\Voucher\Model([
    'owner' => [
        'required'  => true,
        'immutable' => true,
    ],
    'claimed_by' => [
        'required' => true,
    ]
]);

$collection = new Vouchers\Bag($model);
$collection->fill(1000);

$voucher = $collection->pick();

print $voucher; // FHUW-JSUJ-KSIQ-JDUI

Vouchers

Vouchers can take on almost any form, however you can use Vouchers\Voucher\Model to enforce validation and structure. The only required attribute is code which by default is immutable.

$voucher = new Vouchers\Voucher();
print $voucher; // ABCD-EFGH-IJKL

You may also pass an array to the voucher to set pre existing values to the voucher. Matching fields (including code) will be validated.

$voucher = new Voucher(['code' => 'ALAN-COLE-CODE', 'claimed_by' => '', 'claimed_on' => '']);
print $voucher; // "ALAN-COLE-CODE"

Any value passed on voucher creation can be get and set using get() and set() on the voucher.

$voucher->set('owner', 'Alan');
echo $voucher->get('owner'); // Alan

Model

By creating a model you can set default values and validation on vouchers created or loaded. Models are passed as an array to Vouchers\Voucher\Model

$model = new Vouchers\Voucher\Model([
    'owner' => [
        'required'  => true,
        'immutable' => true,
    ],
    'claimed_by' => [
        'required' => true,
    ]
]);

If you set a voucher attribute as immutable then Voucher will throw the ImmutableData exception.

Code

You can change the way the code is generated by settings generator on a model. A generator must implement Vouchers\Voucher\Code\GeneratorInterface

namespace My\Voucher\Generator;

use Vouchers\Voucher\Code\Interface as Generator;

class MyCode implements Generator
{
    public function part()
    {
        return bin2hex(openssl_random_pseudo_bytes(2));
    }

    public function generate()
    {
        return strtoupper(sprintf("%s-%s-%s", $this->part(), $this->part(), $this->part()));
    }

    public function validate()
    {
        return true;
    }
}

Then tell the model to use this generator.

$model = new Vouchers\Voucher\Model([
    'code' => [
        'generator' => \My\Voucher\Generator\MyCode::class
    ]
]);

Bags

Bags act as collections for vouchers and allow you to enforce validations on a whole set. Bags can also act as a selector for vouchers, allowing to you pick a voucher at random and enforce rules on that selection. Bags are also Iterable so they can be used in loops.

$collection = new Vouchers\Bag();
$collection->fill(1000);

foreach($collection as $voucher) {
    print $voucher;
}

You can use Vouchers\Voucher\Model to enfore a model on all items in a bag by passing a model as the first attribute on construction.

$collection = new Vouchers\Bag($model);

You can fill a model with existing vouchers by using add() add will only accept an instance of Vouchers\Voucher

$vouchers = [$voucher1...$voucher100];
foreach ($vouchers as $voucher) {
    $collection->add(new Vouchers\Voucher($voucher));
}

You can also run a map on any array, mapping the return as new vouchers within the bag. This is handy if you need to transform data to fit a model.

$collection->map($vouchers, function ($voucher) {
    return new Vouchers\Voucher($voucher);
});

You can get a voucher by code, which can be used to see if a voucher exists.

$collection = new Vouchers\Bag();
$voucher = new Vouchers\Voucher(['code' => 'special-voucher']);
$collection->add($voucher);

$v = $collection->find("special-voucher");

if ($v) {
    print (string)$v;
} else {
    print "Voucher does not exist.";
}

Pick

You can have the bag pick you a voucher at random by using pick() on any bag.

$collection = new Vouchers\Bag();
$collection->fill(1000);

$collection->pick();

If you wish to validate the selection you can pass a callback to pick which will run until it returns a true or throw an Vouchers\Exceptions\NoValidVouchers exception.

$collection->pick(function ($voucher) {
    return (bool)$voucher->owner == "Alan";
});

try {
    $collection->pick(function ($voucher) {
        return 2 == 1;
    });
} catch (Exception $e) {
    print $e->getMessage();
}

You may also ask pick() to check all validators this bag might have (see Validate) and only return a voucher that is valid. Again this will throw Vouchers\Exceptions\NoValidVouchers is it doesn't find a voucher.

$collection->pickValid();

Validate

You can add validators to a bag, these validators can be used to validate requirements of a voucher using validate() on a bag and passing the voucher code as a parameter.

$collection->validate("ALAN-COLE-CODE");

Validators can be added as callbacks to the validator function, or as a class that implements Vouchers\Voucher\Validator here is an example that assumes a voucher has an expire_date and checks it has not passed.

$collection->validator(function ($voucher) {
    return $voucher->expire_date > new DateTime();
}, "Sorry, this voucher is expired");

try {
    $collection->validate("ALAN-COLE-CODE");
} catch (\Vouchers\Exceptions\VoucherNotValid $e) {
    return $e->getMessage(); // "Sorry, this voucher is expired";
}

Kitchen Sink

This shows how to get vouchers from the subscriptions api, take a requested voucher, validate it and the claim it on the API.

$api = new Discovery\Subscriptions\Api();
$api->setApiKey(getenv("SUBS_API_KEY"));
$api->setAppId(getenv("SUBS_APP_ID"));

$vouchers = $api->getAllVouchers();

$bag = new Vouchers\Bag();
$bag->map($vouchers, function($voucher) {
    return new Vouchers\Voucher($voucher);
});

# Add some validators
$bag->validator(function ($voucher) {
    return $voucher->owner == "Eurosport";
}, "Sorry, this voucher was not valid.");

$bag->validator(function ($voucher) {
    return !$voucher->used;
}, "Sorry, this voucher has been used.");

$bag->validator(function ($voucher) {
    return new DateTime($voucher->valid_till) < new DateTime();
}, "Sorry, this voucher is expired.");

try {
    $voucher = $collection->validate(filter_val(INPUT_POST, "voucher_code", FILTER_SANITIZE_STRING));
    $voucher->set("used", true // not really needed.
    $api->putVoucherClaim($voucher); // because this takes care of it.
} catch (\Vouchers\Exceptions\VoucherNotValid $e) {
    echo $e->getMessage();
}