Better error messages for topic validations

lib/handlers/subscribe.js

@@ -4,7 +4,7 @@ var write = require('../write')
 var fastfall = require('fastfall')
 var Packet = require('aedes-packet')
 var through = require('through2')
-var validateSubscribeTopic = require('./validations').validateSubscribeTopic
+var validateTopic = require('./validations').validateTopic
 var topicActions = fastfall([
   authorize,
   storeSubscriptions,
@@ -37,7 +37,7 @@ function doSubscribe (sub, done) {
 
 function authorize (sub, done) {
   var client = this.client
-  var err = validateSubscribeTopic(sub.topic)
+  var err = validateTopic(sub.topic, 'SUBSCRIBE')
   if (err) {
     return done(err)
   }

lib/handlers/unsubscribe.js

@@ -1,7 +1,7 @@
 'use strict'
 
 var write = require('../write')
-var validateSubscribeTopic = require('./validations').validateSubscribeTopic
+var validateTopic = require('./validations').validateTopic
 
 function UnsubscribeState (client, packet, finish, granted) {
   this.client = client
@@ -16,7 +16,7 @@ function handleUnsubscribe (client, packet, done) {
   var err
 
   for (var i = 0; i < unsubscriptions.length; i++) {
-    err = validateSubscribeTopic(unsubscriptions[i])
+    err = validateTopic(unsubscriptions[i], 'UNSUBSCRIBE')
     if (err) {
       return done(err)
     }

lib/handlers/validations.js

@@ -1,29 +1,29 @@
 'use strict'
 
-function validateSubscribeTopic (topic) {
+function validateTopic (topic, message) {
   var end = topic.length - 1
   var endMinus = end - 1
   var slashInPreEnd = endMinus > 0 && topic.charCodeAt(endMinus) !== 47
   if (topic.length === 0) {
-    return new Error('impossible to subscribe to an empty topic')
+    return new Error('impossible to ' + message + ' to an empty topic')
   }
   for (var i = 0; i < topic.length; i++) {
     switch (topic.charCodeAt(i)) {
       case 35:
         var notAtTheEnd = i !== end
         if (notAtTheEnd || slashInPreEnd) {
-          return new Error('# is only allowed in SUBSCRIBE in the last position')
+          return new Error('# is only allowed in ' + message + ' in the last position')
         }
         break
       case 43:
         var pastChar = i < end - 1 && topic.charCodeAt(i + 1) !== 47
         var preChar = i > 1 && topic.charCodeAt(i - 1) !== 47
         if (pastChar || preChar) {
-          return new Error('+ is only allowed in SUBSCRIBE between /')
+          return new Error('+ is only allowed in ' + message + ' between /')
         }
         break
     }
   }
 }
 
-module.exports.validateSubscribeTopic = validateSubscribeTopic
+module.exports.validateTopic = validateTopic