Bump protocol to v9 and carry talk-circle ids on the presence frame.

Names stay off the wire; a person not in a circle writes an empty member list and topic.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/HSchool.Client/src/net/protocol.test.ts

@@ -262,7 +262,9 @@ describe('decodeServerMessage', () => {
         + 2
         + 2 + personId.length
         + 2 + personNode.length
-        + 1,
+        + 1
+        + 1
+        + 2,
     );
     const view = new DataView(buffer);
     view.setUint8(0, MessageType.ServerPresence);
@@ -296,6 +298,10 @@ describe('decodeServerMessage', () => {
     new Uint8Array(buffer).set(personNode, offset);
     offset += personNode.length;
     view.setUint8(offset, PresenceState.Here);
+    offset += 1;
+    view.setUint8(offset, 0);
+    offset += 1;
+    view.setUint16(offset, 0, true);
 
     expect(decodeServerMessage(buffer)).toEqual({
       type: 'presence',
@@ -308,7 +314,123 @@ describe('decodeServerMessage', () => {
           activityClass: '5А',
         },
       ],
-      people: [{ id: 'f0.c0', nodeId: 'classroom-101', state: PresenceState.Here }],
+      people: [
+        {
+          id: 'f0.c0',
+          nodeId: 'classroom-101',
+          state: PresenceState.Here,
+          talkMemberIds: [],
+          talkTopicId: '',
+        },
+      ],
+    });
+  });
+
+  it('reads a presence person with talk-circle member ids and topic id', () => {
+    const encoder = new TextEncoder();
+    const putString = (target: DataView, at: number, text: Uint8Array): number => {
+      target.setUint16(at, text.length, true);
+      new Uint8Array(target.buffer).set(text, at + 2);
+      return at + 2 + text.length;
+    };
+
+    const corridor = encoder.encode('corridor-1');
+    const selfId = encoder.encode('f0.c0');
+    const partnerId = encoder.encode('f0.c1');
+    const topic = encoder.encode('TopicSport');
+    const buffer = new ArrayBuffer(
+      7
+        + 2
+        + 2
+        + 2 + selfId.length
+        + 2 + corridor.length
+        + 1
+        + 1
+        + 2 + selfId.length
+        + 2 + partnerId.length
+        + 2 + topic.length,
+    );
+    const view = new DataView(buffer);
+    view.setUint8(0, MessageType.ServerPresence);
+    view.setInt32(1, 1, true);
+    view.setUint16(5, 0, true);
+    view.setUint16(7, 1, true);
+    let offset = 9;
+    offset = putString(view, offset, selfId);
+    offset = putString(view, offset, corridor);
+    view.setUint8(offset, PresenceState.Here);
+    offset += 1;
+    view.setUint8(offset, 2);
+    offset += 1;
+    offset = putString(view, offset, selfId);
+    offset = putString(view, offset, partnerId);
+    putString(view, offset, topic);
+
+    expect(decodeServerMessage(buffer)).toEqual({
+      type: 'presence',
+      schoolId: 1,
+      nodes: [],
+      people: [
+        {
+          id: 'f0.c0',
+          nodeId: 'corridor-1',
+          state: PresenceState.Here,
+          talkMemberIds: ['f0.c0', 'f0.c1'],
+          talkTopicId: 'TopicSport',
+        },
+      ],
+    });
+  });
+
+  it('does not carry a person display name in a presence frame', () => {
+    const encoder = new TextEncoder();
+    const putString = (target: DataView, at: number, text: Uint8Array): number => {
+      target.setUint16(at, text.length, true);
+      new Uint8Array(target.buffer).set(text, at + 2);
+      return at + 2 + text.length;
+    };
+
+    const corridor = encoder.encode('corridor-1');
+    const selfId = encoder.encode('f0.c0');
+    const topic = encoder.encode('TopicSport');
+    const buffer = new ArrayBuffer(
+      7 + 2 + 2 + selfId.length + 2 + corridor.length + 1 + 1 + 2 + selfId.length + 2 + topic.length,
+    );
+    const view = new DataView(buffer);
+    view.setUint8(0, MessageType.ServerPresence);
+    view.setInt32(1, 1, true);
+    view.setUint16(5, 0, true);
+    view.setUint16(7, 1, true);
+    let offset = 9;
+    offset = putString(view, offset, selfId);
+    offset = putString(view, offset, corridor);
+    view.setUint8(offset, PresenceState.Here);
+    offset += 1;
+    view.setUint8(offset, 1);
+    offset += 1;
+    offset = putString(view, offset, selfId);
+    putString(view, offset, topic);
+
+    const bytes = new Uint8Array(buffer);
+    const text = new TextDecoder().decode(bytes);
+    expect(text).not.toContain('Мария');
+    expect(text).not.toContain('Иванова');
+    expect(text).not.toContain('Маша');
+    expect(text).toContain('f0.c0');
+    expect(text).toContain('TopicSport');
+    expect(decodeServerMessage(buffer)).toEqual({
+      type: 'presence',
+      schoolId: 1,
+      nodes: [],
+      people: [
+        {
+          id: 'f0.c0',
+          nodeId: 'corridor-1',
+          state: PresenceState.Here,
+          talkMemberIds: ['f0.c0'],
+          talkTopicId: 'TopicSport',
+        },
+      ],
     });
   });
 

src/HSchool.Client/src/net/protocol.ts

@@ -5,7 +5,7 @@
  * changed together and documented in `docs/protocol.md`. All numbers are little-endian.
  */
 
-export const PROTOCOL_VERSION = 8;
+export const PROTOCOL_VERSION = 9;
 
 export const MessageType = {
   ClientHello: 0x01,
@@ -122,6 +122,8 @@ export interface PresencePerson {
   readonly id: string;
   readonly nodeId: string;
   readonly state: number;
+  readonly talkMemberIds: readonly string[];
+  readonly talkTopicId: string;
 }
 
 export interface PresenceMessage {
@@ -375,7 +377,24 @@ function decodePresence(view: DataView): PresenceMessage {
     offset = nodeId.next;
     const state = readU8(view, offset);
     offset += 1;
-    people.push({ id: id.text, nodeId: nodeId.text, state });
+    const memberCount = readU8(view, offset);
+    offset += 1;
+    const talkMemberIds: string[] = [];
+    for (let member = 0; member < memberCount; member++) {
+      const memberId = readString(view, offset);
+      offset = memberId.next;
+      talkMemberIds.push(memberId.text);
+    }
+
+    const topic = readString(view, offset);
+    offset = topic.next;
+    people.push({
+      id: id.text,
+      nodeId: nodeId.text,
+      state,
+      talkMemberIds,
+      talkTopicId: topic.text,
+    });
   }
 
   return { type: 'presence', schoolId, nodes, people };

src/HSchool.Protocol/Messages.cs

@@ -98,8 +98,22 @@ public sealed record PresenceNode(
     string ActivitySubject = "",
     string ActivityClass = "");
 
-/// <summary>One on-campus person. Names are resolved over HTTP, not on this frame.</summary>
-public sealed record PresencePerson(string Id, string NodeId, byte State);
+/// <summary>
+/// One on-campus person. Names are resolved over HTTP, not on this frame. Talk members and
+/// topic are ids; an empty list means the person is not in a circle.
+/// </summary>
+public sealed record PresencePerson(
+    string Id,
+    string NodeId,
+    byte State,
+    IReadOnlyList<string> TalkMemberIds,
+    string TalkTopicId)
+{
+    public PresencePerson(string id, string nodeId, byte state)
+        : this(id, nodeId, state, [], "")
+    {
+    }
+}
 
 /// <summary>
 /// Live occupancy of an open school, about twice a second. Counts and people cover the whole

src/HSchool.Protocol/ProtocolCodec.cs

@@ -202,6 +202,14 @@ public static class ProtocolCodec
         foreach (var person in message.People)
         {
             size += StringSize(person.Id) + StringSize(person.NodeId) + sizeof(byte);
+            var members = person.TalkMemberIds ?? [];
+            size += sizeof(byte);
+            foreach (var memberId in members)
+            {
+                size += StringSize(memberId);
+            }
+
+            size += StringSize(person.TalkTopicId ?? "");
         }
 
         return size;
@@ -242,9 +250,22 @@ public static class ProtocolCodec
         writer.WriteUInt16((ushort)message.People.Count);
         foreach (var person in message.People)
         {
+            var members = person.TalkMemberIds ?? [];
+            if (members.Count > byte.MaxValue)
+            {
+                throw new ProtocolException($"Presence person {person.Id} has {members.Count} talk members; u8 count cannot hold it.");
+            }
+
             writer.WriteString(person.Id);
             writer.WriteString(person.NodeId);
             writer.WriteByte(person.State);
+            writer.WriteByte((byte)members.Count);
+            foreach (var memberId in members)
+            {
+                writer.WriteString(memberId);
+            }
+
+            writer.WriteString(person.TalkTopicId ?? "");
         }
 
         return writer.Position;
@@ -403,7 +424,18 @@ public static class ProtocolCodec
         var people = new PresencePerson[personCount];
         for (var i = 0; i < personCount; i++)
         {
-            people[i] = new PresencePerson(reader.ReadString(), reader.ReadString(), reader.ReadByte());
+            var id = reader.ReadString();
+            var nodeId = reader.ReadString();
+            var state = reader.ReadByte();
+            var memberCount = reader.ReadByte();
+            var members = new string[memberCount];
+            for (var member = 0; member < memberCount; member++)
+            {
+                members[member] = reader.ReadString();
+            }
+
+            var topicId = reader.ReadString();
+            people[i] = new PresencePerson(id, nodeId, state, members, topicId);
         }
 
         return new ServerPresenceMessage(schoolId, nodes, people);

src/HSchool.Protocol/ProtocolConstants.cs

@@ -4,7 +4,7 @@ namespace HSchool.Protocol;
 public static class ProtocolConstants
 {
     /// <summary>Bumped on every breaking change to the binary layout.</summary>
-    public const byte Version = 8;
+    public const byte Version = 9;
 
     /// <summary>Upper bound for a single WebSocket frame accepted by the server.</summary>
     public const int MaxMessageSize = 8 * 1024;