feat: 🎸 add pubrel packet

Author: streamich

src/MqttDecoder.ts

@@ -5,6 +5,7 @@ import {PacketConnect, parseConnect} from './packets/connect';
 import {PacketPublish, parsePublish} from './packets/publish';
 import {PacketPuback, parsePuback} from './packets/puback';
 import {PacketPubrec, parsePubrec} from './packets/pubrec';
+import {PacketPubrel, parsePubrel} from './packets/pubrel';
 
 export class MqttDecoder {
   public state: DECODER_STATE = DECODER_STATE.HEADER;
@@ -32,7 +33,7 @@ export class MqttDecoder {
     this.list = new BufferList();
   }
 
-  public parse(): null | PacketConnect | PacketConnack | PacketPublish | PacketPuback | PacketPubrec {
+  public parse(): null | PacketConnect | PacketConnack | PacketPublish | PacketPuback | PacketPubrec | PacketPubrel {
     this.parseFixedHeader();
     const data = this.parseVariableData();
     if (!data) return null;
@@ -62,6 +63,10 @@ export class MqttDecoder {
         const packet = parsePubrec(b, l, data, this.version);
         return packet;
       }
+      case PACKET_TYPE.PUBREL: {
+        const packet = parsePubrel(b, l, data, this.version);
+        return packet;
+      }
       default: {
         return null;
       }

src/__tests__/MqttDecoder.spec.ts

@@ -246,3 +246,43 @@ describe('PUBREC', () => {
     });
   });
 });
+
+describe('PUBREL', () => {
+  it('parses MQTT 3.1.1 packet', () => {
+    const decoder = new MqttDecoder();
+    decoder.push(Buffer.from([
+      98, 2, // Header
+      0, 2 // Message ID
+    ]));
+    const packet: PacketPubrec = decoder.parse() as PacketPubrec;
+    expect(packet.b).toBe(98);
+    expect(packet.l).toBe(2);
+    expect(packet.i).toBe(2);
+    expect(packet.c).toBe(0);
+    expect(packet.p).toEqual({});
+  });
+
+  it('parses MQTT 5 properties', () => {
+    const decoder = new MqttDecoder();
+    decoder.version = 5;
+    decoder.push(Buffer.from([
+      98, 24, // Header
+      0, 2, // Message ID
+      16, // reason code
+      20, // properties length
+      31, 0, 4, 116, 101, 115, 116, // reasonString
+      38, 0, 4, 116, 101, 115, 116, 0, 4, 116, 101, 115, 116 // userProperties
+    ]));
+    const packet: PacketPubrec = decoder.parse() as PacketPubrec;
+    expect(packet.b).toBe(98);
+    expect(packet.l).toBe(24);
+    expect(packet.i).toBe(2);
+    expect(packet.c).toBe(16);
+    expect(packet.p).toEqual({
+      [PROPERTY.ReasonString]: 'test',
+      [PROPERTY.UserProperty]: [
+        ['test', 'test'],
+      ],
+    });
+  });
+});

src/packets/pubrel.ts

@@ -0,0 +1,38 @@
+import BufferList from 'bl';
+import {Packet, PacketHeaderData} from '../packet';
+import {Properties} from '../types';
+import {parseProps} from '../util/parse';
+
+export interface PacketPubrelData extends PacketHeaderData {
+  /** Packet Identifier. */
+  i: number;
+  /** PUBREL Reason Code. */
+  c: number;
+  /** Properties. */
+  p: Properties;
+}
+
+export class PacketPubrel extends Packet implements PacketPubrelData {
+  constructor(
+    b: number,
+    l: number,
+    public i: number,
+    public c: number,
+    public p: Properties,
+  ) {
+    super(b, l);
+  }
+}
+
+export const parsePubrel = (b: number, l: number, data: BufferList, version: number): PacketPubrel => {
+  const i = data.readUInt16BE(0);
+  let c: number = 0;
+  let p: Properties = {};
+  if (version === 5) {
+    c = data.readUInt8(2);
+    if (l > 3) {
+      [p] = parseProps(data, 3);
+    }
+  }
+  return new PacketPubrel(b, l, i, c, p);
+};