Examples: Add example "How to set discount".

docs/examples/CheckoutAPI/discounts.php

@@ -0,0 +1,93 @@
+<?php
+/**
+ * Copyright 2019 Klarna AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Create a checkout order with discounts.
+ */
+
+require_once dirname(__DIR__) . '/../../vendor/autoload.php';
+
+/**
+ * Follow the link to get your credentials: https://github.com/klarna/kco_rest_php/#api-credentials
+ *
+ * Make sure that your credentials belong to the right endpoint. If you have credentials for the US Playground,
+ * such credentials will not work for the EU Playground and you will get 401 Unauthorized exception.
+ */
+$merchantId = getenv('USERNAME') ?: 'K123456_abcd12345';
+$sharedSecret = getenv('PASSWORD') ?: 'sharedSecret';
+
+/*
+EU_BASE_URL = 'https://api.klarna.com'
+EU_TEST_BASE_URL = 'https://api.playground.klarna.com'
+NA_BASE_URL = 'https://api-na.klarna.com'
+NA_TEST_BASE_URL = 'https://api-na.playground.klarna.com'
+*/
+$apiEndpoint = Klarna\Rest\Transport\ConnectorInterface::EU_TEST_BASE_URL;
+
+$connector = Klarna\Rest\Transport\Connector::create(
+    $merchantId,
+    $sharedSecret,
+    $apiEndpoint
+);
+
+$order = [
+    "purchase_country" => "gb",
+    "purchase_currency" => "gbp",
+    "locale" => "en-gb",
+    "order_amount" => 9000,
+    "order_tax_amount" => 818,
+    "order_lines" => [
+        [
+            "type" => "physical",
+            "reference" => "19-402-USA",
+            "name" => "Red T-Shirt",
+            "quantity" => 1,
+            "quantity_unit" => "pcs",
+            "unit_price" => 10000,
+            "tax_rate" => 1000,
+            "total_amount" => 10000,
+            "total_tax_amount" => 909
+        ],
+
+        // Add discount as an order line
+        [
+            "type" => "discount",
+            "reference" => "10-gbp-order-discount",
+            "name" => "Discount",
+            "quantity" => 1,
+            "unit_price" => -1000,
+            "tax_rate" => 1000,
+            "total_amount" => -1000,
+            "total_tax_amount" => -91
+        ]
+    ],
+    "merchant_urls" => [
+        "terms" => "https://example.com/toc",
+        "checkout" => "https://example.com/checkout?klarna_order_id={checkout.order.id}",
+        "confirmation" => "https://example.com/thank-you?klarna_order_id={checkout.order.id}",
+        "push" => "https://example.com/create_order?klarna_order_id={checkout.order.id}"
+    ]
+];
+
+try {
+    $checkout = new Klarna\Rest\Checkout\Order($connector);
+    $checkout->create($order);
+
+    echo $checkout['html_snippet'];
+} catch (Exception $e) {
+    echo 'Caught exception: ' . $e->getMessage() . "\n";
+}