Add autoEnd option

README.md

@@ -112,6 +112,13 @@ Serve files relative to `path`.
 Byte offset at which the stream starts, defaults to 0. The start is inclusive,
 meaning `start: 2` will include the 3rd byte in the stream.
 
+##### autoEnd
+
+Enable or disable ending the stream of the http response  after pipe, defaults to true.
+Disabling this will ignore the header `Content-Length` which will force 
+the `Transfer-Encoding` to be `chunked`. User can listen the event `end` 
+for further operation. Here is the doc about [pipe]('https://nodejs.org/dist/latest-v6.x/docs/api/stream.html#stream_readable_pipe_destination_options').
+
 #### Events
 
 The `SendStream` is an event emitter and will emit the following events:

index.js

@@ -704,7 +704,9 @@ SendStream.prototype.send = function send (path, stat) {
   opts.end = Math.max(offset, offset + len - 1)
 
   // content-length
-  res.setHeader('Content-Length', len)
+  if (options.autoEnd !== undefined ? options.autoEnd : true) {
+    res.setHeader('Content-Length', len)
+  }
 
   // HEAD support
   if (req.method === 'HEAD') {
@@ -803,7 +805,8 @@ SendStream.prototype.stream = function stream (path, options) {
   // pipe
   var stream = fs.createReadStream(path, options)
   this.emit('stream', stream)
-  stream.pipe(res)
+  var autoEnd = options.autoEnd !== undefined ? options.autoEnd : true
+  stream.pipe(res, {end: autoEnd})
 
   // response finished, done with the fd
   onFinished(res, function onfinished () {

test/send.js

@@ -24,6 +24,22 @@ var app = http.createServer(function (req, res) {
   .pipe(res)
 })
 
+var appPipeNotEnd = http.createServer(function (req, res) {
+  function error (err) {
+    res.statusCode = err.status
+    res.end(http.STATUS_CODES[err.status])
+  }
+
+  function end () {
+    res.end('tobi')
+  }
+
+  send(req, req.url, {root: fixtures, autoEnd: false, acceptRanges: false})
+      .on('error', error)
+      .on('end', end)
+      .pipe(res)
+})
+
 describe('send(file).pipe(res)', function () {
   it('should stream the file contents', function (done) {
     request(app)
@@ -1420,6 +1436,14 @@ describe('send.mime', function () {
   })
 })
 
+describe('send(file).pipe(res,false)', function () {
+  it('should stream the file contents with append', function (done) {
+    request(appPipeNotEnd)
+        .get('/name.txt')
+        .expect(200, 'tobitobi', done)
+  })
+})
+
 function createServer (opts, fn) {
   return http.createServer(function onRequest (req, res) {
     try {