stream: Don't emit 'end' unless read() called

isaacs · isaacs · commit 327b6e3e1de8 · 2013-03-10T11:08:22.000-07:00
This solves the problem of calling `readable.pipe(writable)` after the readable stream has already emitted 'end', as often is the case when writing simple HTTP proxies. The spirit of streams2 is that things will work properly, even if you don't set them up right away on the first tick. This approach breaks down, however, because pipe()ing from an ended readable will just do nothing. No more data will ever arrive, and the writable will hang open forever never being ended. However, that does not solve the case of adding a `on('end')` listener after the stream has received the EOF chunk, if it was the first chunk received (and thus, length was 0, and 'end' got emitted). So, with this, we defer the 'end' event emission until the read() function is called. Also, in pipe(), if the source has emitted 'end' already, we call the cleanup/onend function on nextTick. Piping from an already-ended stream is thus the same as piping from a stream that is in the process of ending. Updates many tests that were relying on 'end' coming immediately, even though they never read() from the req. Fix nodejs#4942
diff --git a/lib/_stream_readable.js b/lib/_stream_readable.js
@@ -49,6 +49,12 @@ function ReadableState(options, stream) {
   this.endEmitted = false;
   this.reading = false;
 
+  // In streams that never have any data, and do push(null) right away,
+  // the consumer can miss the 'end' event if they do some I/O before
+  // consuming the stream.  So, we don't emit('end') until some reading
+  // happens.
+  this.calledRead = false;
+
   // a flag to be able to tell if the onwrite cb is called immediately,
   // or on a later tick.  We set this to true at first, becuase any
   // actions that shouldn't happen until "later" should generally also
@@ -218,6 +224,7 @@ function howMuchToRead(n, state) {
 // you can override either this method, or the async _read(n) below.
 Readable.prototype.read = function(n) {
   var state = this._readableState;
+  state.calledRead = true;
   var nOrig = n;
 
   if (typeof n !== 'number' || n > 0)
@@ -430,13 +437,15 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
   }
   state.pipesCount += 1;
 
-  if ((!pipeOpts || pipeOpts.end !== false) &&
-      dest !== process.stdout &&
-      dest !== process.stderr) {
-    src.once('end', onend);
-  } else {
-    src.once('end', cleanup);
-  }
+  var doEnd = (!pipeOpts || pipeOpts.end !== false) &&
+              dest !== process.stdout &&
+              dest !== process.stderr;
+
+  var endFn = doEnd ? onend : cleanup;
+  if (state.endEmitted)
+    process.nextTick(endFn);
+  else
+    src.once('end', endFn);
 
   dest.on('unpipe', onunpipe);
   function onunpipe(readable) {
@@ -853,12 +862,12 @@ function endReadable(stream) {
   if (state.length > 0)
     throw new Error('endReadable called on non-empty stream');
 
-  if (state.endEmitted)
-    return;
-  state.ended = true;
-  state.endEmitted = true;
-  process.nextTick(function() {
-    stream.readable = false;
-    stream.emit('end');
-  });
+  if (!state.endEmitted && state.calledRead) {
+    state.ended = true;
+    state.endEmitted = true;
+    process.nextTick(function() {
+      stream.readable = false;
+      stream.emit('end');
+    });
+  }
 }
diff --git a/lib/http.js b/lib/http.js
@@ -416,13 +416,13 @@ IncomingMessage.prototype._addHeaderLine = function(field, value) {
 // Call this instead of resume() if we want to just
 // dump all the data to /dev/null
 IncomingMessage.prototype._dump = function() {
-  if (this._dumped)
-    return;
-
-  this._dumped = true;
-  if (this.socket.parser) this.socket.parser.incoming = null;
-  this.push(null);
-  readStart(this.socket);
+  if (!this._dumped) {
+    this._dumped = true;
+    if (this.socket.parser) this.socket.parser.incoming = null;
+    this.push(null);
+    readStart(this.socket);
+    this.read();
+  }
 };
 
 
diff --git a/test/simple/test-http-allow-req-after-204-res.js b/test/simple/test-http-allow-req-after-204-res.js
@@ -58,6 +58,7 @@ function nextRequest() {
         //process.nextTick(nextRequest);
       }
     });
+    response.resume();
   });
   request.end();
 }
diff --git a/test/simple/test-http-client-response-domain.js b/test/simple/test-http-client-response-domain.js
@@ -60,6 +60,7 @@ function test() {
     res.on('end', function() {
       res.emit('error', new Error('should be caught by domain'));
     });
+    res.resume();
   });
   req.end();
 }
diff --git a/test/simple/test-http-contentLength0.js b/test/simple/test-http-contentLength0.js
@@ -36,6 +36,7 @@ s.listen(common.PORT, function() {
   var request = http.request({ port: common.PORT }, function(response) {
     console.log('STATUS: ' + response.statusCode);
     s.close();
+    response.resume();
   });
 
   request.end();
diff --git a/test/simple/test-http-head-request.js b/test/simple/test-http-head-request.js
@@ -47,6 +47,7 @@ server.listen(common.PORT, function() {
       common.error('response end');
       gotEnd = true;
     });
+    response.resume();
   });
   request.end();
 });
diff --git a/test/simple/test-http-head-response-has-no-body-end.js b/test/simple/test-http-head-response-has-no-body-end.js
@@ -51,6 +51,7 @@ server.on('listening', function() {
       server.close();
       responseComplete = true;
     });
+    res.resume();
   });
   common.error('req');
   req.end();
diff --git a/test/simple/test-http-head-response-has-no-body.js b/test/simple/test-http-head-response-has-no-body.js
@@ -48,6 +48,7 @@ server.on('listening', function() {
       server.close();
       responseComplete = true;
     });
+    res.resume();
   });
   common.error('req');
   req.end();
diff --git a/test/simple/test-http-legacy.js b/test/simple/test-http-legacy.js
@@ -61,6 +61,7 @@ var server = http.createServer(function(req, res) {
     res.end();
     responses_sent += 1;
   });
+  req.resume();
 
   //assert.equal('127.0.0.1', res.connection.remoteAddress);
 });
diff --git a/test/simple/test-http-max-headers-count.js b/test/simple/test-http-max-headers-count.js
@@ -75,6 +75,7 @@ server.listen(common.PORT, function() {
           server.close();
         }
       });
+      res.resume();
     });
     req.maxHeadersCount = max;
     req.end();
diff --git a/test/simple/test-http-pipe-fs.js b/test/simple/test-http-pipe-fs.js
@@ -54,6 +54,7 @@ var server = http.createServer(function(req, res) {
             server.close();
           }
         });
+        res.resume();
       });
       req.on('socket', function(s) {
         common.debug('req' + i + ' start');
diff --git a/test/simple/test-http-should-keep-alive.js b/test/simple/test-http-should-keep-alive.js
@@ -59,6 +59,7 @@ var server = net.createServer(function(socket) {
       } else {
         server.close();
       }
+      res.resume();
     });
   }
 
diff --git a/test/simple/test-http.js b/test/simple/test-http.js
@@ -58,6 +58,7 @@ var server = http.Server(function(req, res) {
     res.end();
     responses_sent += 1;
   });
+  req.resume();
 
   //assert.equal('127.0.0.1', res.connection.remoteAddress);
 });
diff --git a/test/simple/test-https-client-reject.js b/test/simple/test-https-client-reject.js
@@ -41,6 +41,7 @@ var server = https.createServer(options, function(req, res) {
   ++reqCount;
   res.writeHead(200);
   res.end();
+  req.resume();
 }).listen(common.PORT, function() {
   unauthorized();
 });
@@ -51,6 +52,7 @@ function unauthorized() {
     rejectUnauthorized: false
   }, function(res) {
     assert(!req.socket.authorized);
+    res.resume();
     rejectUnauthorized();
   });
   req.on('error', function(err) {
@@ -80,6 +82,7 @@ function authorized() {
   };
   options.agent = new https.Agent(options);
   var req = https.request(options, function(res) {
+    res.resume();
     assert(req.socket.authorized);
     server.close();
   });
diff --git a/test/simple/test-stream-pipe-after-end.js b/test/simple/test-stream-pipe-after-end.js
@@ -0,0 +1,86 @@
+// 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 Readable = require('_stream_readable');
+var Writable = require('_stream_writable');
+var util = require('util');
+
+util.inherits(TestReadable, Readable);
+function TestReadable(opt) {
+  if (!(this instanceof TestReadable))
+    return new TestReadable(opt);
+  Readable.call(this, opt);
+  this._ended = false;
+}
+
+TestReadable.prototype._read = function(n) {
+  if (this._ended)
+    this.emit('error', new Error('_read called twice'));
+  this._ended = true;
+  this.push(null);
+};
+
+util.inherits(TestWritable, Writable);
+function TestWritable(opt) {
+  if (!(this instanceof TestWritable))
+    return new TestWritable(opt);
+  Writable.call(this, opt);
+  this._written = [];
+}
+
+TestWritable.prototype._write = function(chunk, encoding, cb) {
+  this._written.push(chunk);
+  cb();
+};
+
+// this one should not emit 'end' until we read() from it later.
+var ender = new TestReadable();
+var enderEnded = false;
+
+// what happens when you pipe() a Readable that's already ended?
+var piper = new TestReadable();
+// pushes EOF null, and length=0, so this will trigger 'end'
+piper.read();
+
+setTimeout(function() {
+  ender.on('end', function() {
+    enderEnded = true;
+  });
+  assert(!enderEnded);
+  var c = ender.read();
+  assert.equal(c, null);
+
+  var w = new TestWritable();
+  var writableFinished = false;
+  w.on('finish', function() {
+    writableFinished = true;
+  });
+  piper.pipe(w);
+
+  process.on('exit', function() {
+    assert(enderEnded);
+    assert(writableFinished);
+    console.log('ok');
+  });
+});

Original file line number	Diff line number	Diff line change
`@@ -58,6 +58,7 @@ function nextRequest() {`
`58`	`58`	`//process.nextTick(nextRequest);`
`59`	`59`	`}`
`60`	`60`	`});`
	`61`	`+ response.resume();`
`61`	`62`	`});`
`62`	`63`	`request.end();`
`63`	`64`	`}`
Original file line number	Diff line number	Diff line change
`@@ -60,6 +60,7 @@ function test() {`
`60`	`60`	`res.on('end', function() {`
`61`	`61`	`res.emit('error', new Error('should be caught by domain'));`
`62`	`62`	`});`
	`63`	`+ res.resume();`
`63`	`64`	`});`
`64`	`65`	`req.end();`
`65`	`66`	`}`
Original file line number	Diff line number	Diff line change
`@@ -75,6 +75,7 @@ server.listen(common.PORT, function() {`
`75`	`75`	`server.close();`
`76`	`76`	`}`
`77`	`77`	`});`
	`78`	`+ res.resume();`
`78`	`79`	`});`
`79`	`80`	`req.maxHeadersCount = max;`
`80`	`81`	`req.end();`