From 466b05c347dccf0b238062ad3c24ab324d60a8b1 Mon Sep 17 00:00:00 2001
From: thosakwe <thosakwe@gmail.com>
Date: Fri, 13 Jan 2017 19:36:38 -0500
Subject: [PATCH] waterfall

---
 README.md                  |  2 +-
 lib/src/http/routable.dart | 20 ++++++++++++++++++++
 pubspec.yaml               |  2 +-
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 991942ff..c26c18c6 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # angel_framework
 
-[![pub 1.0.0-dev.42](https://img.shields.io/badge/pub-1.0.0--dev.42-red.svg)](https://pub.dartlang.org/packages/angel_framework)
+[![pub 1.0.0-dev.43](https://img.shields.io/badge/pub-1.0.0--dev.43-red.svg)](https://pub.dartlang.org/packages/angel_framework)
 [![build status](https://travis-ci.org/angel-dart/framework.svg)](https://travis-ci.org/angel-dart/framework)
 
 Core libraries for the Angel Framework.
diff --git a/lib/src/http/routable.dart b/lib/src/http/routable.dart
index 7206d878..493099b1 100644
--- a/lib/src/http/routable.dart
+++ b/lib/src/http/routable.dart
@@ -19,6 +19,26 @@ typedef Future<bool> RequestMiddleware(RequestContext req, ResponseContext res);
 /// A function that receives an incoming [RequestContext] and responds to it.
 typedef Future RequestHandler(RequestContext req, ResponseContext res);
 
+/// Sequentially runs a list of [handlers] of middleware, and breaks if any does not
+/// return `true`. Works well with [Router].chain.
+RequestMiddleware waterfall(List handlers) {
+  for (var handler in handlers) {
+    if (handler is! RequestMiddleware && handler is! RequestHandler)
+      throw new ArgumentError(
+          '`waterfall` only accepts middleware and handlers. $handler is not a valid option.');
+  }
+
+  return (req, res) async {
+    for (var handler in handlers) {
+      var result = await handler(req, res);
+
+      if (result != true) return result;
+    }
+
+    return true;
+  };
+}
+
 /// A routable server that can handle dynamic requests.
 class Routable extends Router {
   final Map<Pattern, Controller> _controllers = {};
diff --git a/pubspec.yaml b/pubspec.yaml
index 1bb182a8..6da03e3f 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: angel_framework
-version: 1.0.0-dev.42
+version: 1.0.0-dev.43
 description: Core libraries for the Angel framework.
 author: Tobe O <thosakwe@gmail.com>
 homepage: https://github.com/angel-dart/angel_framework