sign: dont convert input buffers to utf8 strings

binary payloads would get mangled due to the unnecessary string
conversion, which should go the other way around

Fixes: #50

Author: omsmith

lib/sign-stream.js

@@ -3,13 +3,13 @@ var base64url = require('base64url');
 var DataStream = require('./data-stream');
 var jwa = require('jwa');
 var Stream = require('stream');
-var toString = require('./tostring');
+var toBuffer = require('./to-buffer');
 var util = require('util');
 
 function jwsSecuredInput(header, payload, encoding) {
   encoding = encoding || 'utf8';
-  var encodedHeader = base64url(toString(header), 'binary');
-  var encodedPayload = base64url(toString(payload), encoding);
+  var encodedHeader = base64url(toBuffer(header));
+  var encodedPayload = base64url(toBuffer(payload, encoding));
   return util.format('%s.%s', encodedHeader, encodedPayload);
 }
 

lib/to-buffer.js

@@ -0,0 +1,19 @@
+'use strict';
+
+var Buffer = require('safe-buffer').Buffer;
+
+module.exports = function toBuffer(val, encoding) {
+	if (Buffer.isBuffer(val)) {
+		return val;
+	}
+	if (typeof val === 'string') {
+		return Buffer.from(val, encoding || 'utf8');
+	}
+	if (typeof val === 'number') {
+		// This won't work for very large or very small numbers, but is consistent
+		// with previous behaviour at least
+		val = val.toString();
+		return Buffer.from(val, 'utf8');
+	}
+	return Buffer.from(JSON.stringify(val), 'utf8');
+};