Fix Data object support (with test)

lib/multipartform.js

@@ -67,8 +67,9 @@ Part.prototype = {
     if (this.value.data) {
 	    header = "Content-Disposition: form-data; name=\"" + this.name + 
   	            "\"; filename=\"" + this.value.filename + "\"\r\n" +
+  	            "Content-Length: " + this.value.data.length + "\r\n" +	
   	            "Content-Type: " + this.value.contentType;
- 	  } if (this.value instanceof File) {
+ 	  } else if (this.value instanceof File) {
   	  header = "Content-Disposition: form-data; name=\"" + this.name + 
   	            "\"; filename=\"" + this.value.filename + "\"\r\n" +
   	            "Content-Length: " + this.value.fileSize + "\r\n" +	
@@ -127,6 +128,10 @@ Part.prototype = {
   	      }); 
   	    })(); // reader() 
   	  });
+     } else if (this.value instanceof Data) {
+  	  stream.write(this.value.data);
+  	  stream.write("\r\n");
+  	  callback();
      } else {
   	  stream.write(this.value + "\r\n");
   	  callback();

test/restler.js

@@ -294,7 +294,26 @@ module.exports['Multipart'] = {
 
       test.done();
     });
-  }
+  },
+
+  'Test multipart request with Data vars': function(test) {
+    rest.post(host, {
+      data: {
+        a: 10,
+        b: rest.data('b.txt', 'text/plain', 'thing'),
+        c: rest.data('c.txt', 'text/plain', new Buffer('thing'))
+      },
+      multipart: true
+    }).on('complete', function(data) {
+      test.re(data, /content-type\: multipart\/form-data/, 'should set "content-type" header');
+      test.re(data, /name="a"(\s)+10/, 'should send a=10');
+      test.re(data, /name="b"; filename="b.txt"\s+Content-Length: 5\s+Content-Type: text\/plain\s+thing\s/, 'should send b=thing');
+      test.re(data, /name="c"; filename="c.txt"\s+Content-Length: 5\s+Content-Type: text\/plain\s+thing\s/, 'should send c=thing');
+      test.re(data, /content-length: 410/, 'should send content-length header');
+
+      test.done();
+    });
+  },
 
 };