fixing issue where navigating to a non-existant category_id caused NodeBB

to crash

src/categories.js

@@ -10,12 +10,8 @@ var	RDB = require('./redis.js'),
 	Categories.getCategoryById = function(category_id, current_user, callback) {
 		
 		Categories.getCategoryData(category_id, function(err, categoryData) {
-			
-			if(err) {
-				callback(false);
-				return;
-			}
-			
+			if (err) return callback(err);
+
 			var category_name = categoryData.name,
 				category_slug = categoryData.slug;
 
@@ -75,7 +71,7 @@ var	RDB = require('./redis.js'),
 						categoryData.show_sidebar = 'hidden';
 						categoryData.no_topics_message = 'show';
 
-						callback(categoryData);
+						callback(null, categoryData);
 					});
 				} else {
 					async.parallel([getTopics, getModerators, getActiveUsers], function(err, results) {
@@ -83,7 +79,7 @@ var	RDB = require('./redis.js'),
 						categoryData.moderator_block_class = results[1].length > 0 ? '' : 'none';
 						categoryData.moderators = results[1];
 						categoryData.active_users = results[2];
-						callback(categoryData);
+						callback(null, categoryData);
 					});
 				}
 
@@ -341,7 +337,10 @@ var	RDB = require('./redis.js'),
 	}
 
 	Categories.getCategoryData = function(cid, callback) {
-		RDB.hgetall('category:' + cid, callback);
+		RDB.exists('category:' + cid, function(err, exists) {
+			if (exists) RDB.hgetall('category:' + cid, callback);
+			else callback(new Error('No category found!'));
+		});
 	}
 	
 	Categories.getCategoryFields = function(cid, fields, callback) {

src/feed.js

@@ -67,7 +67,12 @@
 	};
 
 	Feed.updateCategory = function(cid) {
-		categories.getCategoryById(cid, 0, function(categoryData) {
+		categories.getCategoryById(cid, 0, function(err, categoryData) {
+			if (err) {
+				console.log('Error: Could not update RSS feed for category ' + cid);
+				return;
+			}
+
 			var location = '/category/' + categoryData.category_id + '/' + categoryData.category_name,
 				xml_url = '/category' + cid + '.rss';
 

src/webserver.js

@@ -209,11 +209,8 @@ var express = require('express'),
 			}
 
 			var category_url = cid + (req.params.slug ? '/' + req.params.slug : '');
-			categories.getCategoryById(cid, 0, function(returnData) {
-				if(!returnData) {
-					res.redirect('404');
-					return;
-				}
+			categories.getCategoryById(cid, 0, function(err, returnData) {
+				if(err) return res.redirect('404');
 				
 				res.send(
 					app.build_header(res) +
@@ -379,8 +376,9 @@ var express = require('express'),
 					});
 				break;
 			case 'category' :
-					categories.getCategoryById(req.params.id, uid, function(data) {
-						res.json(data);
+					categories.getCategoryById(req.params.id, uid, function(err, data) {
+						if (!err) res.json(data);
+						else res.send(404);
 					}, req.params.id, uid);
 				break;
 			case 'recent' :