Show a read only link on the pad

node/PadMessageHandler.js

@@ -23,6 +23,7 @@ var padManager = require("./PadManager");
 var Changeset = require("./Changeset");
 var AttributePoolFactory = require("./AttributePoolFactory");
 var authorManager = require("./AuthorManager");
+var readOnlyManager = require("./ReadOnlyManager");
 
 /**
  * A associative array that translates a session to a pad
@@ -507,6 +508,7 @@ function handleClientReady(client, message)
   var authorColorId;
   var pad;
   var historicalAuthorData = {};
+  var readOnlyId;
 
   async.series([
     //get all authordata of this new user
@@ -543,6 +545,14 @@ function handleClientReady(client, message)
               pad = value;
               callback(err);
             });
+          },
+          function(callback)
+          {
+            readOnlyManager.getReadOnlyId(message.padId, function(err, value)
+            {
+              readOnlyId = value;
+              callback(err);
+            });
           }
         ], callback);
       });
@@ -627,6 +637,7 @@ function handleClientReady(client, message)
         },
         "numConnectedUsers": pad2sessions[message.padId].length,
         "isProPad": false,
+        "readOnlyId": readOnlyId,
         "serverTimestamp": new Date().getTime(),
         "globalPadId": message.padId,
         "userId": author,

node/ReadOnlyManager.js

@@ -0,0 +1,74 @@
+/**
+ * The ReadOnlyManager manages the database and rendering releated to read only pads
+ */
+
+/*
+ * 2011 Peter 'Pita' Martischka
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS-IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+var db = require("./db").db;
+var async = require("async");
+
+/**
+ * returns a read only id for a pad
+ * @param {String} padId the id of the pad
+ */
+exports.getReadOnlyId = function (padId, callback)
+{  
+  var readOnlyId;
+  
+  async.waterfall([
+    //check if there is a pad2readonly entry
+    function(callback)
+    {
+      db.get("pad2readonly:" + padId, callback);
+    },
+    function(dbReadOnlyId, callback)
+    {
+      //there is no readOnly Entry in the database, let's create one
+      if(dbReadOnlyId == null)
+      {
+        readOnlyId = randomString(10);
+        
+        db.set("pad2readonly:" + padId, readOnlyId);
+        db.set("readonly2pad:" + readOnlyId, padId);
+      }
+      //there is a readOnly Entry in the database, let's take this one
+      else
+      {
+        readOnlyId = dbReadOnlyId;
+      }
+      
+      callback();
+    }
+  ], function(err)
+  {
+    //return the results
+    callback(err, readOnlyId);
+  })
+}
+
+/**
+ * Generates a random String with the given length. Is needed to generate the read only ids
+ */
+function randomString(len) 
+{
+  // use only numbers and lowercase letters
+  var pieces = [];
+  for(var i=0;i<len;i++) {
+    pieces.push(Math.floor(Math.random()*36).toString(36).slice(-1));
+  }
+  return pieces.join('');
+}