Support for Base64 Content-Transfer-Encoding

[ghost]

We needed to parse base64-encoded attachments, so we wrote a quick patch to formidable to handle 'em. It's a complete hack without any test cases, but I figured I'd throw it upstream anyway, in case someone else needs the feature (or has the time to implement it as a proper patch with test cases and stuff)

index 62c9e3b..2dc52c3 100644
--- a/dep/node_formidable/lib/incoming_form.js
+++ b/dep/node_formidable/lib/incoming_form.js
@@ -256,6 +256,8 @@ IncomingForm.prototype._initMultipart = function(boundary) {
     part.name = null;
     part.filename = null;
     part.mime = null;
+    part.encoding = null;
+    part.base64Buf = '';
     headerField = '';
     headerValue = '';
   };
@@ -283,6 +285,8 @@ IncomingForm.prototype._initMultipart = function(boundary) {
       }
     } else if (headerField == 'content-type') {
       part.mime = headerValue;
+    } else if (headerField == 'content-transfer-encoding') {
+      part.encoding = headerValue;
     }

     headerField = '';
@@ -294,7 +298,14 @@ IncomingForm.prototype._initMultipart = function(boundary) {
   };

   parser.onPartData = function(b, start, end) {
-    part.emit('data', b.slice(start, end));
+    if (part.encoding === 'base64') {
+      part.base64Buf += b.toString('ascii', start, end);
+      var excess = part.base64Buf.length % 4;
+      part.emit('data', new Buffer(part.base64Buf.slice(0, excess ? -excess : undefined), 'base64'
+      part.base64Buf = excess ? part.base64Buf.slice(-excess) : '';
+    } else {
+      part.emit('data', b.slice(start, end));
+    }
   };

   parser.onPartEnd = function() {

Patch is against felixge/node-formidable@6b9ffe3653fe59f035b01ba1f46b5f2650be00ca

[felixge]

I'll be happy to look at anything, but stuff that's not tested will take me longer to merge : )