Use HTML5 FileAPI properties for File class

This does not break backwards compatiblity yet, but future
versions will remove the old property alias.

See: https://github.com/felixge/node-formidable/issues#issue/32

lib/formidable/file.js

@@ -7,29 +7,45 @@ var util = require('./util'),
 function File(properties) {
   EventEmitter.call(this);
 
-  this.length = 0;
+  this.size = 0;
   this.path = null;
-  this.filename = null;
-  this.mime = null;
+  this.name = null;
+  this.type = null;
 
   this._writeStream = null;
 
   for (var key in properties) {
     this[key] = properties[key];
   }
+
+  this._backwardsCompatibility();
 }
 module.exports = File;
 util.inherits(File, EventEmitter);
 
+// @todo Next release: Show error messages when accessing these
+File.prototype._backwardsCompatibility = function() {
+  var self = this;
+  this.__defineGetter__('length', function() {
+    return self.size;
+  });
+  this.__defineGetter__('filename', function() {
+    return self.name;
+  });
+  this.__defineGetter__('mime', function() {
+    return self.type;
+  });
+};
+
 File.prototype.open = function() {
   this._writeStream = new WriteStream(this.path);
 };
 
 File.prototype.write = function(buffer, cb) {
   var self = this;
   this._writeStream.write(buffer, function() {
-    self.length += buffer.length;
-    self.emit('progress', self.length);
+    self.size += buffer.length;
+    self.emit('progress', self.size);
     cb();
   });
 };

lib/formidable/incoming_form.js

@@ -167,8 +167,8 @@ IncomingForm.prototype.handlePart = function(part) {
 
   var file = new File({
     path: this._uploadPath(part.filename),
-    filename: part.filename,
-    mime: part.mime,
+    name: part.filename,
+    type: part.mime,
   });
 
   this.emit('fileBegin', part.name, file);

test/simple/test-file.js

@@ -15,10 +15,10 @@ function test(test) {
 
 test(function constructor() {
   assert.ok(file instanceof EventEmitter);
-  assert.strictEqual(file.length, 0);
+  assert.strictEqual(file.size, 0);
   assert.strictEqual(file.path, null);
-  assert.strictEqual(file.filename, null);
-  assert.strictEqual(file.mime, null);
+  assert.strictEqual(file.name, null);
+  assert.strictEqual(file.type, null);
 
   assert.strictEqual(file._writeStream, null);
 
@@ -55,22 +55,22 @@ test(function write() {
 
     gently.expect(file, 'emit', function (event, bytesWritten) {
       assert.equal(event, 'progress');
-      assert.equal(bytesWritten, file.length);
+      assert.equal(bytesWritten, file.size);
     });
 
     CB_STUB = gently.expect(function writeCb() {
-      assert.equal(file.length, 10);
+      assert.equal(file.size, 10);
     });
 
     cb();
 
     gently.expect(file, 'emit', function (event, bytesWritten) {
       assert.equal(event, 'progress');
-      assert.equal(bytesWritten, file.length);
+      assert.equal(bytesWritten, file.size);
     });
 
     CB_STUB = gently.expect(function writeCb() {
-      assert.equal(file.length, 20);
+      assert.equal(file.size, 20);
     });
 
     cb();

test/simple/test-incoming-form.js

@@ -595,8 +595,8 @@ test(function handlePart() {
 
     gently.expect(FileStub, 'new', function(properties) {
       assert.equal(properties.path, PATH);
-      assert.equal(properties.filename, PART.filename);
-      assert.equal(properties.mime, PART.mime);
+      assert.equal(properties.name, PART.filename);
+      assert.equal(properties.type, PART.mime);
       FILE = this;
 
       gently.expect(form, 'emit', function (event, field, file) {