# Get Started

In this chapter we are going to talk about the most common task: purchasing a product. We assume you already read basic [get it started](https://payum.gitbook.io/payum/get-it-started).

### Installation

The preferred way to install the library is using [composer](http://getcomposer.org/). Run composer require to add dependencies to *composer.json*:

```bash
php composer.phar require payum/paypal-rest php-http/guzzle7-adapter
```

### Configuration

```php
<?php
//config.php

use Payum\Core\PayumBuilder;
use Payum\Core\Payum;

/** @var Payum $payum */
$payum = (new PayumBuilder())
    ->addGateway('paypalRest', [
        'factory' => 'paypal_rest',
        'client_id' => 'REPLACE IT', // Your PayPal REST API cliend ID.
        'client_secret' => 'REPLACE IT', // Your PayPal REST API client secret.
        'config_path' => 'REPLACE IT', // Point to the directory where your skd_config.ini is located.
    ])

    ->getPayum()
;
```

alternatively, set configuration via the `config` option. See PayPal's `sdk_config.ini` for available options.

```php
<?php
//config.php

use Payum\Core\PayumBuilder;
use Payum\Core\Payum;

/** @var Payum $payum */
$payum = (new PayumBuilder())
    ->addGateway('paypalRest', [
        'factory' => 'paypal_rest',
        'client_id' => 'REPLACE IT',
        'client_secret' => 'REPLACE IT',
        'config' => [
            'option1' => 'value1',
            'option2' => 'value2',
        ],
    ])

    ->getPayum()
;
```

### Prepare payment

```php
<?php
// prepare.php

include __DIR__.'/config.php';

use Payum\Core\Model\Payment;

$paymentClass = Payment::class;

/** @var \Payum\Core\Payum $payum */
$storage = $payum->getStorage($paymentClass);

/** @var Payment $payment */
$payment = $storage->create();
$payment->setNumber(uniqid());
$payment->setTotalAmount(200);
$payment->setCurrencyCode('EUR');


$payment->setDetails(array(
  // put here any fields in a gateway format.
));

$storage->update($payment);

$captureToken = $payum->getTokenFactory()->createCaptureToken('paypalRest', $payment, 'done.php');

header('Location: '.$captureToken->getTargetUrl());

```

or if you want to have more control over the payment information sent to PayPal:

```php
<?php
// prepare.php

include __DIR__.'/config.php';

use League\Uri\Http as HttpUri;
use League\Uri\UriModifier;
use PayPal\Api\Amount;
use PayPal\Api\Payer;
use PayPal\Api\RedirectUrls;
use PayPal\Api\Transaction;

$paypalRestPaymentDetailsClass = 'Payum\Paypal\Rest\Model\PaymentDetails';

/** @var \Payum\Core\Payum $payum */
$storage = $payum->getStorage($paypalRestPaymentDetailsClass);

$payment = $storage->create();
$storage->update($payment);

$payer = new Payer();
$payer->payment_method = "paypal";

$amount = new Amount();
$amount->currency = "USD";
$amount->total = "1.00";

$transaction = new Transaction();
$transaction->amount = $amount;
$transaction->description = "This is the payment description.";

$captureToken = $payum->getTokenFactory()->createCaptureToken('paypalRest', $payment, 'done.php');

$redirectUrls = new RedirectUrls();
$redirectUrls->return_url = $captureToken->getTargetUrl();
$redirectUrls->cancel_url = (string) UriModifier::mergeQuery(HttpUri::createFromString($captureToken->getTargetUrl()), 'cancelled=1');

$payment->intent = "sale";
$payment->payer = $payer;
$payment->redirect_urls = $redirectUrls;
$payment->transactions = array($transaction);

$storage->update($payment);

header("Location: ".$captureToken->getTargetUrl());
```

That's it. As you see we configured Paypal Rest `config.php` and set details `prepare.php`. [capture.php](https://payum.gitbook.io/payum/examples/capture-script) and [done.php](https://payum.gitbook.io/payum/examples/done-script) scripts remain same.

***

### Supporting Payum

Payum is an MIT-licensed open source project with its ongoing development made possible entirely by the support of community and our customers. If you'd like to join them, please consider:

* [Become a sponsor](https://github.com/sponsors/Payum)


---

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