Fix #21 - handle empty payloads without crashing

Not uploading any file will cause `Buffer.byteLength` to throw an error if called with an empty array in node >= 7, which is what `concat-stream` will return if no payload is provided.

Remove `concat-stream` in favour of `bl`, which will reliably callback with Buffer instances for empty streams.

README.md

@@ -47,7 +47,7 @@ The middleware will add files to `req.files` in the following form:
 // req.files:
 {
     fieldName: {
-        data: "raw file data",
+        data: Buffer("raw file data"),
         name: "upload.txt",
         encoding: "utf8",
         mimetype: "text/plain",
@@ -77,7 +77,7 @@ If the `multi` property is set:
 // req.files:
 {
     fieldName: [{
-        data: "raw file data",
+        data: Buffer("raw file data"),
         name: "upload.txt",
         encoding: "utf8",
         mimetype: "text/plain",

index.js

@@ -1,6 +1,6 @@
 var Busboy = require('busboy'),
     bytes = require('bytes'),
-    concat = require('concat-stream'),
+    bl = require('bl'),
     debug = require('debug')('busboy-body-parser');
 
 var HARDLIMIT = bytes('250mb');
@@ -41,7 +41,8 @@ module.exports = function (settings) {
                 req.body[key] = value;
             });
             busboy.on('file', function (key, file, name, enc, mimetype) {
-                file.pipe(concat(function (d) {
+                file.pipe(bl(function (err, d) {
+                    if (err || !name) { return; }
                     var fileData = {
                         data: file.truncated ? null : d,
                         name: name,

package.json

@@ -8,13 +8,14 @@
   "license": "MIT",
   "repository": "lennym/busboy-body-parser",
   "dependencies": {
+    "bl": "^1.2.1",
     "busboy": "^0.2.9",
     "bytes": "^2.0.0",
-    "concat-stream": "^1.4.6",
     "debug": "^2.1.0"
   },
   "devDependencies": {
     "chai": "^1.9.2",
+    "express": "^4.16.2",
     "mocha": "^2.0.1",
     "sinon": "^1.11.1",
     "sinon-chai": "^2.6.0"

test/index.js

@@ -96,7 +96,7 @@ describe('multipart form parser', function () {
         parser(req, res, function () {
             req.files.should.have.property('key');
             req.files.key.should.eql({
-                data: 'abc123',
+                data: Buffer('abc123'),
                 name: 'test.jpg',
                 encoding: 'binary',
                 mimetype: 'image/jpeg',
@@ -154,15 +154,15 @@ describe('multipart form parser', function () {
             req.files.should.have.property('key');
             req.files.key.should.length(2);
             req.files.key[0].should.eql({
-                data: 'abc123',
+                data: Buffer('abc123'),
                 name: 'test.jpg',
                 encoding: 'binary',
                 mimetype: 'image/jpeg',
                 size: 6,
                 truncated: false
             });
             req.files.key[1].should.eql({
-                data: 'xyz789',
+                data: Buffer('xyz789'),
                 name: 'test2.jpg',
                 encoding: 'binary',
                 mimetype: 'image/jpeg',
@@ -172,6 +172,46 @@ describe('multipart form parser', function () {
 
             done();
         });
-    })
+    });
+
+    it('can handle empty payloads', function (done) {
+        var file = {
+            pipe: function (s) {
+                s.end();
+                // ensure 'finish' event fires after files are processed
+                process.nextTick(Busboy.prototype.on.withArgs('finish').args[0][1]);
+            },
+            truncated: false
+        };
+        Busboy.prototype.on.withArgs('file').yieldsAsync('key', file, '', '7bit', 'application/octet-stream');
+        parser(req, res, function () {
+            req.files.should.eql({});
+            done();
+        });
+    });
+
+    it('can handle empty files', function (done) {
+        var file = {
+            pipe: function (s) {
+                s.end();
+                // ensure 'finish' event fires after files are processed
+                process.nextTick(Busboy.prototype.on.withArgs('finish').args[0][1]);
+            },
+            truncated: false
+        };
+        Busboy.prototype.on.withArgs('file').yieldsAsync('key', file, 'test.jpg', 'binary', 'image/jpeg');
+        parser(req, res, function () {
+            req.files.should.have.property('key');
+            req.files.key.should.eql({
+                data: Buffer(''),
+                name: 'test.jpg',
+                encoding: 'binary',
+                mimetype: 'image/jpeg',
+                size: 0,
+                truncated: false
+            });
+            done();
+        });
+    });
 
 });