Added document max length limit, enforceMaxLength on change and show modal when reach the limit.

lib/ot/editor-socketio-server.js

@@ -95,6 +95,7 @@ EditorSocketIOServer.prototype.onOperation = function (socket, revision, operati
     try {
         var clientId = socket.id;
         var wrappedPrime = this.receiveOperation(revision, wrapped);
+        if(!wrappedPrime) return;
         //console.log("new operation: " + JSON.stringify(wrapped));
         this.getClient(clientId).selection = wrappedPrime.meta;
         revision = this.operations.length;

lib/ot/server.js

@@ -1,3 +1,5 @@
+var config = require('../../config');
+
 if (typeof ot === 'undefined') {
   var ot = {};
 }
@@ -28,7 +30,10 @@ ot.Server = (function (global) {
     }
 
     // ... and apply that on the document.
-    this.document = operation.apply(this.document);
+    var newDocument = operation.apply(this.document);
+    // ignore if exceed the max length of document
+    if(newDocument.length > config.documentmaxlength) return;
+    this.document = newDocument;
     // Store operation in history.
     this.operations.push(operation);