diff --git a/src/aphront/sink/AphrontHTTPSink.php b/src/aphront/sink/AphrontHTTPSink.php
index 88773cdff0..875aafa3f0 100644
--- a/src/aphront/sink/AphrontHTTPSink.php
+++ b/src/aphront/sink/AphrontHTTPSink.php
@@ -96,13 +96,16 @@ abstract class AphrontHTTPSink {
    * @return void
    */
   final public function writeResponse(AphrontResponse $response) {
+    // Do this first, in case it throws.
+    $response_string = $response->buildResponseString();
+
     $all_headers = array_merge(
       $response->getHeaders(),
       $response->getCacheHeaders());
 
     $this->writeHTTPStatus($response->getHTTPResponseCode());
     $this->writeHeaders($all_headers);
-    $this->writeData($response->buildResponseString());
+    $this->writeData($response_string);
   }
 
 
diff --git a/webroot/index.php b/webroot/index.php
index 1f56a1d0bd..53069daeac 100644
--- a/webroot/index.php
+++ b/webroot/index.php
@@ -26,6 +26,8 @@ try {
   PhutilErrorHandler::setErrorListener(
     array('DarkConsoleErrorLogPluginAPI', 'handleErrors'));
 
+  $sink = new AphrontPHPHTTPSink();
+
   if (PhabricatorEnv::getEnvConfig('phabricator.setup')) {
     try {
       PhabricatorSetup::runSetup();
@@ -48,7 +50,6 @@ try {
       break;
   }
 
-
   $application->setHost($host);
   $application->setPath($path);
   $application->willBuildRequest();
@@ -100,7 +101,9 @@ try {
     $response = $controller->didProcessRequest($response);
     $response = $application->willSendResponse($response, $controller);
     $response->setRequest($request);
-    $response_string = $response->buildResponseString();
+
+    $sink->writeResponse($response);
+
   } catch (Exception $ex) {
     $write_guard->dispose();
     if ($access_log) {
@@ -119,18 +122,6 @@ try {
 
   $write_guard->dispose();
 
-  // TODO: Share the $sink->writeResponse() pathway here?
-
-  $sink = new AphrontPHPHTTPSink();
-  $sink->writeHTTPStatus($response->getHTTPResponseCode());
-
-  $headers = $response->getCacheHeaders();
-  $headers = array_merge($headers, $response->getHeaders());
-
-  $sink->writeHeaders($headers);
-
-  $sink->writeData($response_string);
-
   if ($access_log) {
     $request_start = PhabricatorStartup::getStartTime();
     $access_log->setData(