From f4e8c022d1f81e7f2f462e4a1d9d2801f7f17fcd Mon Sep 17 00:00:00 2001
From: Aaron Stannard <aaron@petabridge.com>
Date: Sat, 13 Apr 2024 12:59:39 -0500
Subject: [PATCH] fixed the ASCII indicator for MQTT 3.1.1

---
 src/TurboMqtt.Core/Protocol/MqttEncoder.cs          | 13 +++++++------
 .../Packets/Connect/ConnectPacketMqtt311Specs.cs    |  4 ++--
 .../Packets/Connect/ConnectPacketMqtt5Specs.cs      |  6 +++---
 3 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/src/TurboMqtt.Core/Protocol/MqttEncoder.cs b/src/TurboMqtt.Core/Protocol/MqttEncoder.cs
index a562b9bb..2bdee046 100644
--- a/src/TurboMqtt.Core/Protocol/MqttEncoder.cs
+++ b/src/TurboMqtt.Core/Protocol/MqttEncoder.cs
@@ -9,12 +9,13 @@
 
 namespace TurboMqtt.Core.Protocol;
 
-public static class MqttEncoder
+internal static class MqttPacketSizeEstimator
 {
-    private const int PacketIdLength = 2;
-    private const int StringSizeLength = 2;
-    private const int MaxVariableLength = 4;
-    private const string Mqtt5ProtocolName = "MQTT";
+    internal const int PacketIdLength = 2;
+    internal const int StringSizeLength = 2;
+    internal const int MaxVariableLength = 4;
+    internal const string Mqtt5ProtocolName = "MQTT";
+    internal const string Mqtt311ProtocolName = "MQIsdp";
     
     /// <summary>
     /// Estimates the size of the packet WITHOUT the length header.
@@ -212,7 +213,7 @@ private static int EstimateConnectPacketSizeMqtt311(ConnectPacket packet)
         
         // Protocol Name (2 bytes length + actual length of string)
 
-        size += 2 + Encoding.ASCII.GetByteCount(Mqtt5ProtocolName); // MQTT uses ASCII, not UTF8, for the protocol name: https://www.emqx.com/en/blog/mqtt-5-0-control-packets-01-connect-connack#connect-packet-structure
+        size += 2 + Encoding.ASCII.GetByteCount(Mqtt311ProtocolName); // MQTT uses ASCII, not UTF8, for the protocol name: https://www.emqx.com/en/blog/mqtt-5-0-control-packets-01-connect-connack#connect-packet-structure
         
         // Protocol Version (1 byte)
         size += 1;
diff --git a/tests/TurboMqtt.Core.Tests/Packets/Connect/ConnectPacketMqtt311Specs.cs b/tests/TurboMqtt.Core.Tests/Packets/Connect/ConnectPacketMqtt311Specs.cs
index b43ffe10..847a749a 100644
--- a/tests/TurboMqtt.Core.Tests/Packets/Connect/ConnectPacketMqtt311Specs.cs
+++ b/tests/TurboMqtt.Core.Tests/Packets/Connect/ConnectPacketMqtt311Specs.cs
@@ -120,7 +120,7 @@ [Fact] public void should_estimate_correct_size()
                 TopicAliasMaximum = 5, // should be ignored - only supported in MQTT 5.0
             };
             
-            MqttEncoder.EstimatePacketSize(connectPacket, MqttProtocolVersion.V3_1_1).Should().Be(49);
+            MqttPacketSizeEstimator.EstimatePacketSize(connectPacket, MqttProtocolVersion.V3_1_1).Should().Be(51);
         }
         
         // estimate the packet size without username and password
@@ -134,7 +134,7 @@ [Fact] public void should_estimate_correct_size_without_username_password()
                 TopicAliasMaximum = 5, // should be ignored - only supported in MQTT 5.0
             };
             
-            MqttEncoder.EstimatePacketSize(connectPacket, MqttProtocolVersion.V3_1_1).Should().Be(34);
+            MqttPacketSizeEstimator.EstimatePacketSize(connectPacket, MqttProtocolVersion.V3_1_1).Should().Be(36);
         }
     }
 }
\ No newline at end of file
diff --git a/tests/TurboMqtt.Core.Tests/Packets/Connect/ConnectPacketMqtt5Specs.cs b/tests/TurboMqtt.Core.Tests/Packets/Connect/ConnectPacketMqtt5Specs.cs
index 404271b1..7a17e52a 100644
--- a/tests/TurboMqtt.Core.Tests/Packets/Connect/ConnectPacketMqtt5Specs.cs
+++ b/tests/TurboMqtt.Core.Tests/Packets/Connect/ConnectPacketMqtt5Specs.cs
@@ -85,7 +85,7 @@ public void should_estimate_correct_packet_size()
         {
             var packet = new ConnectPacket("clientId", MqttProtocolVersion.V5_0);
 
-            MqttEncoder.EstimatePacketSize(packet, MqttProtocolVersion.V5_0).Should().Be(42);
+            MqttPacketSizeEstimator.EstimatePacketSize(packet, MqttProtocolVersion.V5_0).Should().Be(42);
         }
 
         [Fact]
@@ -100,7 +100,7 @@ public void should_estimate_correct_packet_size_with_properties()
                 }
             };
 
-            MqttEncoder.EstimatePacketSize(packet, MqttProtocolVersion.V5_0).Should().Be(52);
+            MqttPacketSizeEstimator.EstimatePacketSize(packet, MqttProtocolVersion.V5_0).Should().Be(52);
         }
 
         [Fact]
@@ -127,7 +127,7 @@ public void should_estimate_correct_packet_size_with_will()
             };
             
 
-            MqttEncoder.EstimatePacketSize(packet, MqttProtocolVersion.V5_0).Should().Be(77);
+            MqttPacketSizeEstimator.EstimatePacketSize(packet, MqttProtocolVersion.V5_0).Should().Be(77);
         }
     }
 }
\ No newline at end of file