From 2bc3bb73274d95a74cc911b3eb486a4f383405df Mon Sep 17 00:00:00 2001
From: Jonathan Ong <jonathanrichardong@gmail.com>
Date: Fri, 24 Jan 2014 14:38:40 -0800
Subject: [PATCH] this.respond=false for bypassing koa's response handling

closes #198
---
 docs/api/context.md |  6 ++++++
 lib/application.js  |  2 ++
 test/application.js | 25 +++++++++++++++++++++++++
 3 files changed, 33 insertions(+)

diff --git a/docs/api/context.md b/docs/api/context.md
index 0fb0032..576fdf1 100644
--- a/docs/api/context.md
+++ b/docs/api/context.md
@@ -102,6 +102,12 @@ throw err;
   error messages since you do not want to leak failure
   details.
 
+### ctx.respond
+
+  To bypass Koa's built-in response handling, you may explicitly set `this.respond = false;`. Use this if you want to write to the raw `res` object instead of letting Koa handle the response for you.
+
+  Note that using this is __not__ supported by Koa. This may break intended functionality of Koa middleware and Koa itself. Using this properly is considered a hack and is only a convenience to those wishing to use traditional `fn(req, res)` functions and middleware within Koa.
+
 ## Request aliases
 
   The following accessors and alias [Request](request.md) equivalents:
diff --git a/lib/application.js b/lib/application.js
index 5918241..40790a2 100644
--- a/lib/application.js
+++ b/lib/application.js
@@ -184,6 +184,8 @@ function *respond(next){
 
   yield *next;
 
+  if (false === this.respond) return;
+
   var res = this.res;
   if (res.headersSent || !res.socket.writable) return;
 
diff --git a/test/application.js b/test/application.js
index 1aefe3e..6b81549 100644
--- a/test/application.js
+++ b/test/application.js
@@ -94,6 +94,31 @@ describe('app.use(fn)', function(){
 })
 
 describe('app.respond', function(){
+  describe('when this.respond === false', function(){
+    it('should bypass app.respond', function(done){
+      var app = koa();
+
+      app.use(function *(){
+        this.body = 'Hello';
+        this.respond = false;
+
+        var res = this.res;
+        setImmediate(function () {
+          res.setHeader('Content-Type', 'text/plain');
+          res.end('lol');
+        })
+      })
+
+      var server = app.listen();
+
+      request(server)
+      .get('/')
+      .expect(200)
+      .expect('lol')
+      .end(done);
+    })
+  })
+
   describe('when HEAD is used', function(){
     it('should not respond with the body', function(done){
       var app = koa();