Separate AuthHelper class for authentication purpose

Author: tareqtms

lib/AuthHelper.php

@@ -0,0 +1,166 @@
+<?php
+/**
+ * Created by PhpStorm.
+ * @author Tareq Mahmood <tareqtms@yahoo.com>
+ * Created at: 8/27/16 10:58 AM UTC+06:00
+ */
+
+namespace PHPShopify;
+
+
+use PHPShopify\Exception\SdkException;
+
+class AuthHelper
+{
+    /**
+     * Return the admin url, based on a given shop url
+     *
+     * @param string $shopUrl
+     * @param string $apiKey
+     * @param string $apiPassword
+     * @return string
+     */
+    public static function getAdminUrl($shopUrl, $apiKey = null, $apiPassword = null)
+    {
+        //Remove https:// and trailing slash (if provided)
+        $shopUrl = preg_replace('#^https?://|/$#', '', $shopUrl);
+
+        if($apiKey && $apiPassword) {
+            $adminUrl = "https://$apiKey:$apiPassword@$shopUrl/admin/";
+        } else {
+            $adminUrl = "https://$shopUrl/admin/";
+        }
+        return $adminUrl;
+    }
+
+    /**
+     * Get the url of the current page
+     *
+     * @return string
+     */
+    public static function getCurrentUrl()
+    {
+        if (isset($_SERVER['HTTPS']) &&
+            ($_SERVER['HTTPS'] == 'on' || $_SERVER['HTTPS'] == 1) ||
+            isset($_SERVER['HTTP_X_FORWARDED_PROTO']) &&
+            $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https') {
+            $protocol = 'https';
+        }
+        else {
+            $protocol = 'http';
+        }
+
+        return "$protocol://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
+    }
+
+    /**
+     * Verify if the request is made from shopify using hmac hash value
+     *
+     * @throws SdkException if SharedSecret is not provided or hmac is not found in the url parameters
+     *
+     * @return bool
+     */
+    public static function verifyShopifyRequest()
+    {
+        $data = $_GET;
+
+        if(!isset(ShopifyClient::$config['SharedSecret'])) {
+            throw new SdkException("Please provide SharedSecret while configuring the SDK client.");
+        }
+
+        $sharedSecret = ShopifyClient::$config['SharedSecret'];
+
+        //Get the hmac and remove it from array
+        if (isset($data['hmac'])) {
+            $hmac = $data['hmac'];
+            unset($data['hmac']);
+        } else {
+            throw new SdkException("HMAC value not found in url parameters.");
+        }
+        //signature validation is deprecated
+        if (isset($data['signature'])) {
+            unset($data['signature']);
+        }
+        //Create data string for the remaining url parameters
+        $dataString = http_build_query($data);
+
+        $realHmac = hash_hmac('sha256', $dataString, $sharedSecret);
+
+        //hash the values before comparing (to prevent time attack)
+        if(md5($realHmac) === md5($hmac)) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     * Redirect the user to the authorization page to allow the app access to the shop
+     *
+     * @see https://help.shopify.com/api/guides/authentication/oauth#scopes For allowed scopes
+     *
+     * @param string|string[] $scopes Scopes required by app
+     * @param string $redirectUrl
+     *
+     * @throws SdkException if required configuration is not provided in $config
+     *
+     * @return void
+     */
+    public static function createAuthRequest($scopes, $redirectUrl = null)
+    {
+        $config = ShopifyClient::$config;
+
+        if(!isset($config['ShopUrl']) || !isset($config['ApiKey'])) {
+            throw new SdkException("ShopUrl and ApiKey are required for authentication request. Please check SDK configuration!");
+        }
+
+        if (!$redirectUrl) {
+            if(!isset($config['SharedSecret'])) {
+                throw new SdkException("SharedSecret is required for getting access token. Please check SDK configuration!");
+            }
+
+            //If redirect url is the same as this url, then need to check for access token when redirected back from shopify
+            if(isset($_GET['code'])) {
+                return self::getAccessToken($config);
+            } else {
+                $redirectUrl = self::getCurrentUrl();
+            }
+        }
+
+        if (is_array($scopes)) {
+            $scopes = join(',', $scopes);
+        }
+        $authUrl = $config['ApiUrl'] . 'oauth/authorize?client_id=' . $config['ApiKey'] . '&redirect_uri=' . $redirectUrl . "&scope=$scopes";
+
+        header("Location: $authUrl");
+    }
+
+    /**
+     * Get Access token for the API
+     * Call this when being redirected from shopify page ( to the $redirectUrl) after authentication
+     *
+     * @throws SdkException if SharedSecret or ApiKey is missing in SDK configuration
+     *
+     * @return string
+     */
+    public static function getAccessToken()
+    {
+        $config = ShopifyClient::$config;
+
+        if(!isset($config['SharedSecret']) || !isset($config['ApiKey'])) {
+            throw new SdkException("SharedSecret and ApiKey are required for getting access token. Please check SDK configuration!");
+        }
+
+        if(self::verifyShopifyRequest()) {
+            $data = array(
+                'client_id' => $config['ApiKey'],
+                'client_secret' => $config['SharedSecret'],
+                'code' => $_GET['code'],
+            );
+
+            $response = HttpRequestJson::post($config['ApiUrl'] . 'oauth/access_token', $data);
+
+            return isset($response['access_token']) ? $response['access_token'] : null;
+        }
+    }
+}