Configurable Headers for All Requests to PayPal

- Allows adding additional headers to every call to PayPal APIs.
- Refactored OAuthTokenCredential to share code for making Rest Calls
- SDK Config to add headers with http.headers.* syntax
- Fixes #193

lib/PayPal/Rest/ApiContext.php

@@ -58,6 +58,26 @@ class ApiContext
         return $this->credential;
     }
 
+    public function getRequestHeaders()
+    {
+        $result = PPConfigManager::getInstance()->get('http.headers');
+        $headers = array();
+        foreach ($result as $header => $value) {
+            $headerName = ltrim($header, 'http.headers');
+            $headers[$headerName] = $value;
+        }
+        return $headers;
+    }
+
+    public function addRequestHeader($name, $value)
+    {
+        // Determine if the name already has a 'http.headers' prefix. If not, add one.
+        if (!(substr($name, 0, strlen('http.headers')) === 'http.headers')) {
+            $name = 'http.headers.' . $name;
+        }
+        PPConfigManager::getInstance()->addConfigs(array($name => $value));
+    }
+
     /**
      * Get Request ID
      *

lib/PayPal/Rest/OauthHandler.php

@@ -0,0 +1,105 @@
+<?php
+/**
+ * API handler for OAuth Token Request REST API calls
+ */
+
+namespace PayPal\Rest;
+
+use PayPal\Common\PPUserAgent;
+use PayPal\Core\PPConstants;
+use PayPal\Core\PPHttpConfig;
+use PayPal\Exception\PPConfigurationException;
+use PayPal\Exception\PPInvalidCredentialException;
+use PayPal\Exception\PPMissingCredentialException;
+use PayPal\Handler\IPPHandler;
+
+/**
+ * Class OauthHandler
+ */
+class OauthHandler implements IPPHandler
+{
+    /**
+     * Private Variable
+     *
+     * @var \Paypal\Rest\ApiContext $apiContext
+     */
+    private $apiContext;
+
+    /**
+     * Construct
+     *
+     * @param \Paypal\Rest\ApiContext $apiContext
+     */
+    public function __construct($apiContext)
+    {
+        $this->apiContext = $apiContext;
+    }
+
+    /**
+     * @param PPHttpConfig $httpConfig
+     * @param string                    $request
+     * @param mixed                     $options
+     * @return mixed|void
+     * @throws PPConfigurationException
+     * @throws PPInvalidCredentialException
+     * @throws PPMissingCredentialException
+     */
+    public function handle($httpConfig, $request, $options)
+    {
+        $config = $this->apiContext->getConfig();
+
+        $httpConfig->setUrl(
+            rtrim(trim($this->_getEndpoint($config)), '/') .
+            (isset($options['path']) ? $options['path'] : '')
+        );
+
+        $headers = array(
+            "User-Agent"    => PPUserAgent::getValue(PPConstants::SDK_NAME, PPConstants::SDK_VERSION),
+            "Authorization" => "Basic " . base64_encode($options['clientId'] . ":" . $options['clientSecret']),
+            "Accept"        => "*/*"
+        );
+        $httpConfig->setHeaders($headers);
+
+        // Add any additional Headers that they may have provided
+        $headers = $this->apiContext->getRequestHeaders();
+        foreach ($headers as $key => $value) {
+            $httpConfig->addHeader($key, $value);
+        }
+    }
+
+    /**
+     * Get HttpConfiguration object for OAuth API
+     *
+     * @param array $config
+     *
+     * @return PPHttpConfig
+     * @throws \PayPal\Exception\PPConfigurationException
+     */
+    private static function _getEndpoint($config)
+    {
+        if (isset($config['oauth.EndPoint'])) {
+            $baseEndpoint = $config['oauth.EndPoint'];
+        } else if (isset($config['service.EndPoint'])) {
+            $baseEndpoint = $config['service.EndPoint'];
+        } else if (isset($config['mode'])) {
+            switch (strtoupper($config['mode'])) {
+                case 'SANDBOX':
+                    $baseEndpoint = PPConstants::REST_SANDBOX_ENDPOINT;
+                    break;
+                case 'LIVE':
+                    $baseEndpoint = PPConstants::REST_LIVE_ENDPOINT;
+                    break;
+                default:
+                    throw new PPConfigurationException('The mode config parameter must be set to either sandbox/live');
+            }
+        } else {
+            throw new PPConfigurationException(
+                'You must set one of service.endpoint or mode parameters in your configuration'
+            );
+        }
+
+        $baseEndpoint = rtrim(trim($baseEndpoint), '/') . "/v1/oauth2/token";
+
+        return $baseEndpoint;
+    }
+}

lib/PayPal/Rest/RestHandler.php

@@ -84,6 +84,11 @@ class RestHandler implements IPPHandler
         if ($httpConfig->getMethod() == 'POST' || $httpConfig->getMethod() == 'PUT') {
             $httpConfig->addHeader('PayPal-Request-Id', $this->apiContext->getRequestId());
         }
+        // Add any additional Headers that they may have provided
+        $headers = $this->apiContext->getRequestHeaders();
+        foreach ($headers as $key => $value) {
+            $httpConfig->addHeader($key, $value);
+        }
     }
 
     /**