diff --git a/flight/Engine.php b/flight/Engine.php
index 554a93f..6130c41 100644
--- a/flight/Engine.php
+++ b/flight/Engine.php
@@ -466,7 +466,8 @@ class Engine {
 
         $this->response()->header('ETag', $id);
 
-        if ($id === getenv('HTTP_IF_NONE_MATCH')) {
+        if (isset($_SERVER['HTTP_IF_NONE_MATCH']) &&
+            $_SERVER['HTTP_IF_NONE_MATCH'] === $id) {
             $this->halt(304);
         }
     }
@@ -479,7 +480,8 @@ class Engine {
     public function _lastModified($time) {
         $this->response()->header('Last-Modified', date(DATE_RFC1123, $time));
 
-        if ($time === strtotime(getenv('HTTP_IF_MODIFIED_SINCE'))) {
+        if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) &&
+            strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) === $time) {
             $this->halt(304);
         }
     }
diff --git a/flight/net/Request.php b/flight/net/Request.php
index 0100634..051bc07 100644
--- a/flight/net/Request.php
+++ b/flight/net/Request.php
@@ -132,23 +132,23 @@ class Request {
         // Default properties
         if (empty($config)) {
             $config = array(
-                'url' => getenv('REQUEST_URI') ?: '/',
-                'base' => str_replace(array('\\',' '), array('/','%20'), dirname(getenv('SCRIPT_NAME'))),
-                'method' => getenv('REQUEST_METHOD') ?: 'GET',
-                'referrer' => getenv('HTTP_REFERER') ?: '',
-                'ip' => getenv('REMOTE_ADDR') ?: '',
-                'ajax' => getenv('HTTP_X_REQUESTED_WITH') == 'XMLHttpRequest',
-                'scheme' => getenv('SERVER_PROTOCOL') ?: 'HTTP/1.1',
-                'user_agent' => getenv('HTTP_USER_AGENT') ?: '',
+                'url' => $this->server('REQUEST_URI', '/'),
+                'base' => str_replace(array('\\',' '), array('/','%20'), dirname($this->server('SCRIPT_NAME'))),
+                'method' => $this->server('REQUEST_METHOD', 'GET'),
+                'referrer' => $this->server('HTTP_REFERER'),
+                'ip' => $this->server('REMOTE_ADDR'),
+                'ajax' => $this->server('HTTP_X_REQUESTED_WITH') == 'XMLHttpRequest',
+                'scheme' => $this->server('SERVER_PROTOCOL', 'HTTP/1.1'),
+                'user_agent' => $this->server('HTTP_USER_AGENT'),
                 'body' => file_get_contents('php://input'),
-                'type' => getenv('CONTENT_TYPE') ?: '',
-                'length' => getenv('CONTENT_LENGTH') ?: 0,
+                'type' => $this->server('CONTENT_TYPE'),
+                'length' => $this->server('CONTENT_LENGTH', 0),
                 'query' => new Collection($_GET),
                 'data' => new Collection($_POST),
                 'cookies' => new Collection($_COOKIE),
                 'files' => new Collection($_FILES),
-                'secure' => getenv('HTTPS') && getenv('HTTPS') != 'off',
-                'accept' => getenv('HTTP_ACCEPT') ?: '',
+                'secure' => $this->server('HTTPS', 'off') != 'off',
+                'accept' => $this->server('HTTP_ACCEPT'),
                 'proxy_ip' => $this->getProxyIpAddress()
             );
         }
@@ -225,4 +225,11 @@ class Request {
 
         return '';
     }
+
+  /**
+   * Get variable from $_SERVER using $default if not provided
+   */
+  private function server($var, $default='') {
+    return isset($_SERVER[$var]) ? $_SERVER[$var] : $default;
+  }
 }
diff --git a/flight/net/Response.php b/flight/net/Response.php
index c2d6ca9..69a12fc 100644
--- a/flight/net/Response.php
+++ b/flight/net/Response.php
@@ -187,7 +187,7 @@ class Response {
                 header(
                     sprintf(
                         '%s %d %s',
-                        getenv('SERVER_PROTOCOL') ?: 'HTTP/1.1',
+                        (isset($_SERVER['SERVER_PROTOCOL']) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.1'),
                         $this->status,
                         self::$codes[$this->status]),
                     true,
diff --git a/tests/RedirectTest.php b/tests/RedirectTest.php
index a877653..d35b221 100644
--- a/tests/RedirectTest.php
+++ b/tests/RedirectTest.php
@@ -25,7 +25,7 @@ class RedirectTest extends PHPUnit_Framework_TestCase
     }
 
     function setUp() {
-        putenv('SCRIPT_NAME=/subdir/index.php');
+        $_SERVER['SCRIPT_NAME'] = '/subdir/index.php';
 
         $this->app = new \flight\Engine();
         $this->app->set('flight.base_url', '/testdir');
diff --git a/tests/RequestTest.php b/tests/RequestTest.php
index f28a96e..1b6acae 100644
--- a/tests/RequestTest.php
+++ b/tests/RequestTest.php
@@ -17,13 +17,12 @@ class RequestTest extends PHPUnit_Framework_TestCase
     private $request;
 
     function setUp() {
-        putenv('REQUEST_URI=/');
-        putenv('SCRIPT_NAME=/index.php');
-        putenv('REQUEST_METHOD=GET');
-        putenv('HTTP_X_REQUESTED_WITH=XMLHttpRequest');
-        putenv('REQUEST_URI=/');
-        putenv('REMOTE_ADDR=8.8.8.8');
-        putenv('HTTPS=on');
+        $_SERVER['REQUEST_URI'] = '/';
+        $_SERVER['SCRIPT_NAME'] = '/index.php';
+        $_SERVER['REQUEST_METHOD'] = 'GET';
+        $_SERVER['HTTP_X_REQUESTED_WITH'] = 'XMLHttpRequest';
+        $_SERVER['REMOTE_ADDR'] = '8.8.8.8';
+        $_SERVER['HTTPS'] = 'on';
         $_SERVER['HTTP_X_FORWARDED_FOR'] = '32.32.32.32';
 
         $this->request = new \flight\net\Request();
@@ -48,7 +47,7 @@ class RequestTest extends PHPUnit_Framework_TestCase
     }
 
     function testSubdirectory() {
-        putenv('SCRIPT_NAME=/subdir/index.php');
+        $_SERVER['SCRIPT_NAME'] = '/subdir/index.php';
 
         $request = new \flight\net\Request();
 
@@ -56,7 +55,7 @@ class RequestTest extends PHPUnit_Framework_TestCase
     }
 
     function testQueryParameters() {
-        putenv('REQUEST_URI=/page?id=1&name=bob');
+        $_SERVER['REQUEST_URI'] = '/page?id=1&name=bob';
 
         $request = new \flight\net\Request();
 
@@ -66,7 +65,7 @@ class RequestTest extends PHPUnit_Framework_TestCase
     }
 
     function testCollections() {
-        putenv('REQUEST_URI=/page?id=1');
+        $_SERVER['REQUEST_URI'] = '/page?id=1';
 
         $_GET['q'] = 1;
         $_POST['q'] = 1;