Can request for message size when fetch.

lib/imap.js

@@ -862,7 +862,10 @@ ImapConnection.prototype._fetch = function(which, uids, options) {
   if (extensions)
     cmd += extensions;
   cmd += 'UID FLAGS INTERNALDATE';
-  cmd += (opts.request.struct ? ' BODYSTRUCTURE' : '');
+  if(opts.request.struct)
+    cmd += ' BODYSTRUCTURE';
+  if(opts.request.size)
+    cmd += ' RFC822.SIZE';
   if (toFetch !== undefined) {
     cmd += ' BODY';
     if (!opts.markSeen)

lib/imap.parsers.js

@@ -59,6 +59,8 @@ exports.parseFetch = function(str, literals, fetchData) {
       fetchData.flags = result[i+1].filter(utils.isNotEmpty);
     else if (result[i] === 'BODYSTRUCTURE')
       fetchData.structure = exports.parseBodyStructure(result[i+1], literals);
+    else if (result[i] === 'RFC822.SIZE')
+      fetchData.size = parseInt(result[i+1], 10);
     else if (typeof result[i] === 'string') // simple extensions
       fetchData[result[i].toLowerCase()] = result[i+1];
   }