Few fixes, but still very broken for some streams.

Need to go back and rethink the approach.

Author: seangarner

lib/buffer-peek-stream.js

@@ -28,7 +28,6 @@ function BufferPeekStream(bytes) {
 util.inherits(BufferPeekStream, stream.Transform);
 module.exports = BufferPeekStream;
 
-
 BufferPeekStream.prototype._transform = function _transform(chunk, enc, callback) {
   // buffer incoming chunks until we have enough for our peek
   this.__buffer.push(chunk);
@@ -56,34 +55,41 @@ BufferPeekStream.prototype.__stopPeeking = function __stopPeeking() {
   // unpipe from upstream
   this.__src.unpipe(this);
 
-  //TODO: find out if this stream can still get data after unpiping under any circumstance 
-
-  var buffer = Buffer.concat(this.__buffer);
-  var source = this.__src;
-
-  // push exactly the number of bytes we wanted to peek
-  this.push(buffer.slice(0, this.__peekBytes));
-  this.push(null);
-
-  if (source._readableState.ended) {
+  if (this.__src._readableState.ended) {
     // if the source has ended then we need to modify its state so it'll start flowing again when we
     // unshift the data back on.  these settings were naively obtained by creating a file read
     // stream of a tiny file then leaving it hang for a timeout of 5s and dumping the state
-    source.readable = true;
-    source._readableState.ended = true;
-    source._readableState.endEmitted = false;
-    source._readableState.ranOut = false;
-    source._readableState.reading = false;
-    source._readableState.calledRead = true;
-    source._readableState.sync = false;
-    source._readableState.needReadable = false;
-    source._readableState.emittedReadable = true;
-    source._readableState.readableListening = false;
-    source._readableState.readingMore = false;
+    this.__src.readable = true;
+    this.__src._readableState.ended = false;
+    this.__src._readableState.endEmitted = false;
+    this.__src._readableState.ranOut = false;
+    this.__src._readableState.reading = false;
+    this.__src._readableState.calledRead = true;
+    this.__src._readableState.sync = false;
+    this.__src._readableState.needReadable = false;
+    this.__src._readableState.emittedReadable = true;
+    this.__src._readableState.readableListening = false;
+    this.__src._readableState.readingMore = false;
+
+    // flush before end is called on this stream
+    flush.call(this);
+  } else {
+
+    // flush once we've emptied this streams buffer through the transform function
+    this.once('drain', flush.bind(this));
   }
 
-  source.unshift(buffer);
+  function flush() {
+    var buffer = Buffer.concat(this.__buffer);
 
-  // we don't need to keep the original buffers
-  this.__buffer = null;
+    // push exactly the number of bytes we wanted to peek
+    this.push(buffer.slice(0, this.__peekBytes));
+
+    // put the whole buffer back onto the start of the origin stream
+    this.__src.unshift(buffer);
+    this.__src = null;
+    this.__buffer = null;
+
+    this.push(null);
+  }
 };

lib/index.js

@@ -7,15 +7,21 @@ peek.Constructor = BufferPeekStream;
 function peek(input, bytes, cb) {
   if (typeof bytes === 'function') {
     cb = bytes;
-    bytes = 65536; // 64K
+    bytes = 16384; // 16K
   }
 
   // make sure we don't callback more than once
   cb = once(cb);
 
   var _ = new BufferPeekStream(bytes);
 
-  _.once('data', function (data) {
+  var data;
+
+  _.once('data', function (d) {
+    data = d;
+  });
+
+  _.once('end', function () {
     cb(null, data);
   });
 

package.json

@@ -1,10 +1,10 @@
 {
   "name": "buffer-peek-stream",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "description": "Transform stream that lets you inspect the start of a ReadStream before deciding what to do with it",
   "main": "lib/index.js",
   "scripts": {
-    "test": "mocha test/buffer-peek-stream.js"
+    "test": "mocha test.js"
   },
   "repository": {
     "type": "git",
@@ -22,5 +22,10 @@
   "bugs": {
     "url": "https://github.com/seangarner/node-buffer-peek-stream/issues"
   },
-  "homepage": "https://github.com/seangarner/node-buffer-peek-stream"
+  "homepage": "https://github.com/seangarner/node-buffer-peek-stream",
+  "devDependencies": {
+    "chai": "^1.9.2",
+    "mocha": "^2.0.1",
+    "randomstring": "^1.0.3"
+  }
 }