pkg/shelf - send Date header in shelf_io

pkg/shelf/lib/shelf_io.dart

Index: pkg/shelf/lib/shelf_io.dart
diff --git a/pkg/shelf/lib/shelf_io.dart b/pkg/shelf/lib/shelf_io.dart
index d8d4d9ca3175e9b0cfea38c36302eeee00bfeb22..98fd319a6873b35ee3d394142e15270d5fb634d8 100644
--- a/pkg/shelf/lib/shelf_io.dart
+++ b/pkg/shelf/lib/shelf_io.dart
@@ -52,7 +52,12 @@ void serveRequests(Stream<HttpRequest> requests, Handler handler) {
 /// Uses [handler] to handle [request].
 ///
 /// Returns a [Future] which completes when the request has been handled.
-Future handleRequest(HttpRequest request, Handler handler) {
+///
+/// If [includeDateHeader] is `true`, the `Date` header is included with a value
+/// of `new DateTime.now` at the time the response is written. The default is
+/// `true`.

[nweiz, 2014/05/27 19:52:44]

Why is this configurable? Any configuration that's included in shelf_io runs the
risk of becoming standard for all adapters, which increases the barrier to entry
of writing a new adapter.

I don't think we should make this configurable without a clear use case for
configuring it.

[kevmoo, 2014/05/27 20:50:58]

DONE

I guess we can always add this later if demand arises.

+Future handleRequest(HttpRequest request, Handler handler,
+    {bool includeDateHeader: true}) {
   var shelfRequest = _fromHttpRequest(request);
 
   // TODO(nweiz): abstract out hijack handling to make it easier to implement an
@@ -83,7 +88,7 @@ Future handleRequest(HttpRequest request, Handler handler) {
       throw new Exception(message.toString().trim());
     }
 
-    return _writeResponse(response, request.response);
+    return _writeResponse(response, request.response, includeDateHeader);
   }).catchError((error, stackTrace) {
     // Ignore HijackExceptions.
     if (error is! HijackException) throw error;
@@ -109,7 +114,8 @@ Request _fromHttpRequest(HttpRequest request) {
       body: request, onHijack: onHijack);
 }
 
-Future _writeResponse(Response response, HttpResponse httpResponse) {
+Future _writeResponse(Response response, HttpResponse httpResponse,
+    bool includeDateHeader) {
   httpResponse.statusCode = response.statusCode;
 
   response.headers.forEach((header, value) {
@@ -121,6 +127,11 @@ Future _writeResponse(Response response, HttpResponse httpResponse) {
     var value = httpResponse.headers.value(HttpHeaders.SERVER);
     httpResponse.headers.set(HttpHeaders.SERVER, '$value with Shelf');
   }
+
+  if (includeDateHeader && !response.headers.containsKey(HttpHeaders.DATE)) {
+    httpResponse.headers.date = new DateTime.now().toUtc();
+  }
+
   return httpResponse.addStream(response.read())
       .then((_) => httpResponse.close());
 }