http: Consistent 'finish' event semantics

In other Writable streams, the 'finish' event means that all of the data
was written, and flushed to the underlying system.

The 'prefinish' event means that end() was called, and all of the data
was processed, but not necessarily completely flushed.

This change brings the http OutgoingMessage classes more in sync with
the other Writable classes throughout Node.

Unfortunately, this change highlights an issue with http
IncomingMessages, where the _dump() method will not actually pull the
data off the wire.  This is a minor issue that is typically only
relevant in test cases, and will be addressed in the next commit.

lib/_http_outgoing.js

@@ -477,6 +477,16 @@ OutgoingMessage.prototype.end = function(data, encoding, callback) {
   if (this.finished) {
     return false;
   }
+
+  var self = this;
+  function finish() {
+    self.emit('finish');
+  }
+
+  if (util.isFunction(callback))
+    this.once('finish', callback);
+
+
   if (!this._header) {
     this._implicitHeader();
   }
@@ -497,10 +507,10 @@ OutgoingMessage.prototype.end = function(data, encoding, callback) {
   }
 
   if (this.chunkedEncoding) {
-    ret = this._send('0\r\n' + this._trailer + '\r\n', 'ascii', callback);
+    ret = this._send('0\r\n' + this._trailer + '\r\n', 'ascii', finish);
   } else {
     // Force a flush, HACK.
-    ret = this._send('', 'ascii', callback);
+    ret = this._send('', 'ascii', finish);
   }
 
   if (this.connection && data)
@@ -521,7 +531,7 @@ OutgoingMessage.prototype.end = function(data, encoding, callback) {
 
 OutgoingMessage.prototype._finish = function() {
   assert(this.connection);
-  this.emit('finish');
+  this.emit('prefinish');
 };
 
 

lib/_http_server.js

@@ -429,7 +429,7 @@ function connectionListener(socket) {
 
     // When we're finished writing the response, check if this is the last
     // respose, if so destroy the socket.
-    res.on('finish', resOnFinish);
+    res.on('prefinish', resOnFinish);
     function resOnFinish() {
       // Usually the first incoming element should be our request.  it may
       // be that in the case abortIncoming() was called that the incoming

test/simple/test-http-byteswritten.js

@@ -26,12 +26,19 @@ var http = require('http');
 
 var body = 'hello world\n';
 
+var sawFinish = false;
+process.on('exit', function() {
+  assert(sawFinish);
+  console.log('ok');
+});
+
 var httpServer = http.createServer(function(req, res) {
+  httpServer.close();
+
   res.on('finish', function() {
+    sawFinish = true;
     assert(typeof(req.connection.bytesWritten) === 'number');
     assert(req.connection.bytesWritten > 0);
-    httpServer.close();
-    console.log('ok');
   });
   res.writeHead(200, { 'Content-Type': 'text/plain' });
 
@@ -51,6 +58,9 @@ var httpServer = http.createServer(function(req, res) {
 });
 
 httpServer.listen(common.PORT, function() {
-  http.get({ port: common.PORT });
+  // XXX(isaacs): This should not be necessary.
+  http.get({ port: common.PORT }, function(res) {
+    res.resume();
+  });
 });
 

test/simple/test-http-outgoing-finish.js

@@ -0,0 +1,74 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var common = require('../common');
+var assert = require('assert');
+
+var http = require('http');
+
+http.createServer(function(req, res) {
+  write(res);
+  req.resume();
+  this.close();
+}).listen(common.PORT, function() {
+  var req = http.request({
+    port: common.PORT,
+    method: 'PUT'
+  });
+  write(req);
+  req.on('response', function(res) {
+    res.resume();
+  });
+});
+
+var buf = new Buffer(1024 * 16);
+buf.fill('x');
+function write(out) {
+  var name = out.constructor.name;
+  var finishEvent = false;
+  var endCb = false;
+
+  // first, write until it gets some backpressure
+  while (out.write(buf)) {}
+
+  // now end, and make sure that we don't get the 'finish' event
+  // before the tick where the cb gets called.  We give it until
+  // nextTick because this is added as a listener before the endcb
+  // is registered.  The order is not what we're testing here, just
+  // that 'finish' isn't emitted until the stream is fully flushed.
+  out.on('finish', function() {
+    finishEvent = true;
+    console.error('%s finish event', name);
+    process.nextTick(function() {
+      assert(endCb, name + ' got finish event before endcb!');
+      console.log('ok - %s finishEvent', name);
+    });
+  });
+
+  out.end(buf, function() {
+    endCb = true;
+    console.error('%s endCb', name);
+    process.nextTick(function() {
+      assert(endCb, name + ' got endCb event before finishEvent!');
+      console.log('ok - %s endCb', name);
+    });
+  });
+}