Limit fetch message count

SyncerWeb.js

@@ -11,6 +11,8 @@ const multer = require('multer');
 
 const css = require('css');
 
+const MAX_FETCH = 100;
+
 module.exports = SyncerWeb;
 
 function SyncerWeb(syncer, pg, cfg)
@@ -153,6 +155,8 @@ SyncerWeb.prototype.get_messages = function*(req, res)
     if (!folderId)
         return res.status(500).send('Need `folderId` query parameter');
     var limit = req.query.limit || 50;
+    if (limit > MAX_FETCH)
+        limit = MAX_FETCH;
     var offset = req.query.offset || 0;
     var [ msgs ] = yield this.pg.select('*').from('messages').where({ folder_id: folderId })
         .orderBy('time desc').limit(limit).offset(offset).rows(gen.ef());