add new style middleware support through @jonathanong's koa-compose patch

benchmarks/middleware.js

@@ -9,20 +9,16 @@ var n = parseInt(process.env.MW || '1', 10);
 console.log('  %s middleware', n);
 
 while (n--) {
-  app.use(function(next){
+  app.use(function *(next){
-    return function *(){
+    yield next;
-      yield next;
-    }
   });
 }
 
 var body = new Buffer('Hello World');
 
-app.use(function(next){
+app.use(function *(next){
-  return function *(){
+  yield next;
-    yield next;
+  this.body = body;
-    this.body = body;
-  }
 });
 
 app.listen(3333);

lib/application.js

@@ -126,15 +126,13 @@ app.context = function(obj){
 
 app.callback = function(){
   var mw = [respond].concat(this.middleware);
-  var fn = compose(mw)(downstream);
+  var gen = compose(mw);
   var self = this;
 
   return function(req, res){
     var ctx = new self.Context(self, req, res);
 
-    co.call(ctx, function *(){
+    co.call(ctx, gen)(function(err){
-      yield fn;
-    })(function(err){
       if (err) ctx.onerror(err);
     });
   }
@@ -157,68 +155,58 @@ app.onerror = function(err){
  * Response middleware.
  */
 
-function respond(next){
+function *respond(next){
-  return function *respond(){
+  this.status = 200;
-    this.status = 200;
+  if (this.app.poweredBy) this.set('X-Powered-By', 'koa');
-    if (this.app.poweredBy) this.set('X-Powered-By', 'koa');
 
-    yield next;
+  yield next;
 
-    var app = this.app;
+  var app = this.app;
-    var res = this.res;
+  var res = this.res;
-    var body = this.body;
+  var body = this.body;
-    var head = 'HEAD' == this.method;
+  var head = 'HEAD' == this.method;
-    var noContent = 204 == this.status || 304 == this.status;
+  var noContent = 204 == this.status || 304 == this.status;
 
-    // 404
+  // 404
-    if (null == body && 200 == this.status) {
+  if (null == body && 200 == this.status) {
-      this.status = 404;
+    this.status = 404;
-    }
-
-    // ignore body
-    if (noContent) return res.end();
-
-    // status body
-    if (null == body) {
-      this.type = 'text';
-      body = http.STATUS_CODES[this.status];
-    }
-
-    // Buffer body
-    if (Buffer.isBuffer(body)) {
-      if (head) return res.end();
-      return res.end(body);
-    }
-
-    // string body
-    if ('string' == typeof body) {
-      if (head) return res.end();
-      return res.end(body);
-    }
-
-    // Stream body
-    if (body instanceof Stream) {
-      if (!~body.listeners('error').indexOf(this.onerror)) body.on('error', this.onerror);
-      if (head) return res.end();
-      return body.pipe(res);
-    }
-
-    // body: json
-    body = JSON.stringify(body, null, this.app.jsonSpaces);
-    this.length = Buffer.byteLength(body);
-    if (head) return res.end();
-    res.end(body);
   }
+
+  // ignore body
+  if (noContent) return res.end();
+
+  // status body
+  if (null == body) {
+    this.type = 'text';
+    body = http.STATUS_CODES[this.status];
+  }
+
+  // Buffer body
+  if (Buffer.isBuffer(body)) {
+    if (head) return res.end();
+    return res.end(body);
+  }
+
+  // string body
+  if ('string' == typeof body) {
+    if (head) return res.end();
+    return res.end(body);
+  }
+
+  // Stream body
+  if (body instanceof Stream) {
+    if (!~body.listeners('error').indexOf(this.onerror)) body.on('error', this.onerror);
+    if (head) return res.end();
+    return body.pipe(res);
+  }
+
+  // body: json
+  body = JSON.stringify(body, null, this.app.jsonSpaces);
+  this.length = Buffer.byteLength(body);
+  if (head) return res.end();
+  res.end(body);
 }
 
-/**
- * Default downstream middleware.
- *
- * @api private
- */
-
-function *downstream(){}
-
 /**
  * Create a new `Context` constructor.
  *

package.json

@@ -21,12 +21,12 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "co": "2.0.0",
+    "co": "2.2.0",
     "debug": "*",
     "mime": "1.2.10",
     "fresh": "0.2.0",
     "negotiator": "0.2.7",
-    "koa-compose": "1.0.0",
+    "koa-compose": "2.0.0",
     "cookies": "~0.3.6"
   },
   "devDependencies": {

test/application.js

@@ -10,28 +10,22 @@ describe('app.use(fn)', function(){
     var app = koa();
     var calls = [];
 
-    app.use(function(next){
+    app.use(function *(next){
-      return function *(){
+      calls.push(1);
-        calls.push(1);
+      yield next;
-        yield next;
+      calls.push(6);
-        calls.push(6);
-      }
     });
 
-    app.use(function(next){
+    app.use(function *(next){
-      return function *(){
+      calls.push(2);
-        calls.push(2);
+      yield next;
-        yield next;
+      calls.push(5);
-        calls.push(5);
-      }
     });
 
-    app.use(function(next){
+    app.use(function *(next){
-      return function *(){
+      calls.push(3);
-        calls.push(3);
+      yield next;
-        yield next;
+      calls.push(4);
-        calls.push(4);
-      }
     });
 
     var server = app.listen();
@@ -51,10 +45,8 @@ describe('app.respond', function(){
     it('should not respond with the body', function(done){
       var app = koa();
 
-      app.use(function(next){
+      app.use(function *(){
-        return function *(){
+        this.body = 'Hello';
-          this.body = 'Hello';
-        }
       });
 
       var server = app.listen();
@@ -87,10 +79,8 @@ describe('app.respond', function(){
     it('should respond with the associated status message', function(done){
       var app = koa();
 
-      app.use(function(next){
+      app.use(function *(){
-        return function *(){
+        this.status = 400;
-          this.status = 400;
-        }
       });
 
       var server = app.listen();
@@ -106,10 +96,8 @@ describe('app.respond', function(){
     it('should respond', function(done){
       var app = koa();
 
-      app.use(function(next){
+      app.use(function *(){
-        return function *(){
+        this.body = 'Hello';
-          this.body = 'Hello';
-        }
       });
 
       var server = app.listen();
@@ -124,10 +112,8 @@ describe('app.respond', function(){
     it('should respond', function(done){
       var app = koa();
 
-      app.use(function(next){
+      app.use(function *(){
-        return function *(){
+        this.body = new Buffer('Hello');
-          this.body = new Buffer('Hello');
-        }
       });
 
       var server = app.listen();
@@ -142,11 +128,9 @@ describe('app.respond', function(){
     it('should respond', function(done){
       var app = koa();
 
-      app.use(function(next){
+      app.use(function *(){
-        return function *(){
+        this.body = fs.createReadStream('package.json');
-          this.body = fs.createReadStream('package.json');
+        this.set('Content-Type', 'application/json');
-          this.set('Content-Type', 'application/json');
-        }
       });
 
       var server = app.listen();
@@ -165,11 +149,9 @@ describe('app.respond', function(){
     it('should handle errors', function(done){
       var app = koa();
 
-      app.use(function(next){
+      app.use(function *(){
-        return function *(){
+        this.set('Content-Type', 'application/json');
-          this.set('Content-Type', 'application/json');
+        this.body = fs.createReadStream('does not exist');
-          this.body = fs.createReadStream('does not exist');
-        }
       });
 
       var server = app.listen();
@@ -186,10 +168,8 @@ describe('app.respond', function(){
     it('should respond with json', function(done){
       var app = koa();
 
-      app.use(function(next){
+      app.use(function *(){
-        return function *(){
+        this.body = { hello: 'world' };
-          this.body = { hello: 'world' };
-        }
       });
 
       var server = app.listen();
@@ -206,10 +186,8 @@ describe('app.respond', function(){
 
         app.jsonSpaces = 0;
 
-        app.use(function(next){
+        app.use(function *(){
-          return function *(){
+          this.body = { hello: 'world' };
-            this.body = { hello: 'world' };
-          }
         });
 
         var server = app.listen();
@@ -226,10 +204,8 @@ describe('app.respond', function(){
     it('should emit "error" on the app', function(done){
       var app = koa();
 
-      app.use(function(next){
+      app.use(function *(){
-        return function *(){
+        throw new Error('boom');
-          throw new Error('boom');
-        }
       });
 
       app.on('error', function(err){
@@ -246,13 +222,11 @@ describe('app.respond', function(){
       it('should expose the message', function(done){
         var app = koa();
 
-        app.use(function(next){
+        app.use(function *(){
-          return function *(){
+          var err = new Error('sorry!');
-            var err = new Error('sorry!');
+          err.status = 403;
-            err.status = 403;
+          err.expose = true;
-            err.expose = true;
+          throw err;
-            throw err;
-          }
         });
 
         request(app.listen())
@@ -266,12 +240,10 @@ describe('app.respond', function(){
       it('should respond with .status', function(done){
         var app = koa();
 
-        app.use(function(next){
+        app.use(function *(){
-          return function *(){
+          var err = new Error('s3 explodes');
-            var err = new Error('s3 explodes');
+          err.status = 403;
-            err.status = 403;
+          throw err;
-            throw err;
-          }
         });
 
         request(app.listen())
@@ -284,10 +256,8 @@ describe('app.respond', function(){
     it('should respond with 500', function(done){
       var app = koa();
 
-      app.use(function(next){
+      app.use(function *(){
-        return function *(){
+        throw new Error('boom!');
-          throw new Error('boom!');
-        }
       });
 
       var server = app.listen();
@@ -301,23 +271,19 @@ describe('app.respond', function(){
     it('should be catchable', function(done){
       var app = koa();
 
-      app.use(function(next){
+      app.use(function *(next){
-        return function *(){
+        try {
-          try {
+          yield next;
-            yield next;
+          this.body = 'Hello';
-            this.body = 'Hello';
+        } catch (err) {
-          } catch (err) {
+          error = err;
-            error = err;
+          this.body = 'Got error';
-            this.body = 'Got error';
-          }
         }
       });
 
-      app.use(function(next){
+      app.use(function *(next){
-        return function *(){
+        throw new Error('boom!');
-          throw new Error('boom!');
+        this.body = 'Oh no';
-          this.body = 'Oh no';
-        }
       });
 
       var server = app.listen();
@@ -339,12 +305,10 @@ describe('app.context(obj)', function(){
       b: 2
     });
 
-    app.use(function(next){
+    app.use(function *(next){
-      return function *(){
+      this.a.should.equal(1);
-        this.a.should.equal(1);
+      this.b.should.equal(2);
-        this.b.should.equal(2);
+      this.status = 204;
-        this.status = 204;
-      }
     });
 
     var server = app.listen();
@@ -368,13 +332,11 @@ describe('app.context(obj)', function(){
       }
     });
 
-    app.use(function(next){
+    app.use(function *(next){
-      return function *(){
+      this.something.should.equal('hi');
-        this.something.should.equal('hi');
+      this.something = 'hello';
-        this.something = 'hello';
+      this.something.should.equal('hello');
-        this.something.should.equal('hello');
+      this.status = 204;
-        this.status = 204;
-      }
     });
 
     var server = app.listen();
@@ -396,12 +358,10 @@ describe('app.context(obj)', function(){
       b: 2
     });
 
-    app.use(function(next){
+    app.use(function *(){
-      return function *(){
+      this.a.should.equal(1);
-        this.a.should.equal(1);
+      this.b.should.equal(2);
-        this.b.should.equal(2);
+      this.status = 204;
-        this.status = 204;
-      }
     });
 
     var server = app.listen();
@@ -420,11 +380,9 @@ describe('app.context(obj)', function(){
       a: 1
     });
 
-    app2.use(function(next){
+    app2.use(function *(next){
-      return function *(){
+      assert.equal(this.a, undefined);
-        assert.equal(this.a, undefined);
+      this.status = 204;
-        this.status = 204;
-      }
     });
 
     var server = http.createServer(app2.callback());