Add username from CONNECT to client after authenticate succes

docs/Client.md

@@ -72,6 +72,15 @@ It is available only after `CONNACK (rc=0)`, otherwise it is `null` in cases:
 - after `CONNACK (rc!=0)` response
 - `connectionError` raised by aedes
 
+## client.username
+
+- `<string>` __Default__: `null`
+
+Client username, specified by CONNECT packet.
+
+It is available only after a successful call to `aedes.authenticate()`, where it
+will be set to the username specifed by the client, or `null` if no username was supplied.
+
 ## client.clean
 
 - `<boolean>` __Default__: `true`

lib/handlers/connect.js

@@ -98,9 +98,10 @@ function init (client, packet, done) {
 function authenticate (arg, done) {
   const client = this.client
   client.pause()
+  let username = this.username;
   client.broker.authenticate(
     client,
-    this.packet.username,
+    username,
     this.packet.password,
     negate)
 
@@ -113,6 +114,10 @@ function authenticate (arg, done) {
     }
     if (!err && successful) {
       client._authorized = true
+      if (typeof(client.username) == "undefined") {
+        // check it's undefined, it could have been set in preConnect
+        client.username = username || null;
+      }
       return done()
     }