fix: announce a presence channel user once across all of their sockets

database/factories/MemberFactory.php

@@ -30,6 +30,9 @@ public function definition()
         return [
             'channel_id' => Channel::factory(),
             'socket_id'  => fake()->uuid,
+            'user_id'    => fn (array $attributes) => isset($attributes['data']['user_id'])
+                ? (string) $attributes['data']['user_id']
+                : null,
             'data'       => null,
         ];
     }

database/migrations/2026_10_13_120000_add_user_id_to_pollcast_channel_members_table.php

@@ -0,0 +1,29 @@
+<?php declare(strict_types=1);
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /** @var string */
+    private $table = 'pollcast_channel_members';
+
+    public function up(): void
+    {
+        Schema::table($this->table, function (Blueprint $table) {
+            $table->string('user_id', 191)->nullable()->after('socket_id');
+            $table->index(['channel_id', 'user_id']);
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table($this->table, function (Blueprint $table) {
+            $table->dropForeign(['channel_id']);
+            $table->dropIndex(['channel_id', 'user_id']);
+            $table->dropColumn('user_id');
+            $table->foreign('channel_id')->references('id')->on('pollcast_channel')->cascadeOnDelete();
+        });
+    }
+};

src/Broadcasting/Socket.php

@@ -176,7 +176,10 @@ public function joinChannel(string $name, ?array $data = null): void
         $member = Member::query()->firstOrCreate([
             'channel_id' => $channel->id,
             'socket_id'  => $this->getId(),
-        ], ['data' => $data]);
+        ], [
+            'user_id' => isset($data['user_id']) ? (string) $data['user_id'] : null,
+            'data'    => $data,
+        ]);
         $member->touch();
 
         if ($data === null) {
@@ -194,6 +197,10 @@ public function removeMemberFromChannel(Member $member, Channel $channel): void
             return;
         }
 
+        if ($this->hasAnotherSocket($member)) {
+            return;
+        }
+
         (new Message([
             'channel_id' => $channel->id,
             // The member's own socket, not the request's - garbage collection removes members
@@ -215,9 +222,19 @@ protected function joinedPresenceChannel(Channel $channel, Member $member, array
             'channel_id' => $channel->id,
             'member_id'  => $member->id,
             'event'      => 'pollcast:subscription_succeeded',
-            'payload'    => Member::query()->where('channel_id', $channel->id)->pluck('data'),
+            'payload'    => Member::query()
+                ->where('channel_id', $channel->id)
+                ->get()
+                ->unique(fn (Member $m) => $m->user_id ?? $m->socket_id)
+                ->pluck('data')
+                ->values(),
         ]))->save();
 
+        // A user is announced once, however many sockets they have on the channel.
+        if (! $this->isEarliestSocket($member)) {
+            return;
+        }
+
         // Broadcast member added event to everyone else in the channel - the joiner already
         // has themselves in the subscription_succeeded member list.
         (new Message([
@@ -228,6 +245,37 @@ protected function joinedPresenceChannel(Channel $channel, Member $member, array
         ]))->save();
     }
 
+    private function hasAnotherSocket(Member $member): bool
+    {
+        if ($member->user_id === null) {
+            return false;
+        }
+
+        return Member::query()
+            ->where('channel_id', $member->channel_id)
+            ->where('user_id', $member->user_id)
+            ->where('id', '!=', $member->id)
+            ->exists();
+    }
+
+    /**
+     * Whether this is the user's earliest socket on the channel, which is the one that announces them. Unlike
+     * checking for any other socket, two sockets which join at the same time cannot both decide not to.
+     */
+    private function isEarliestSocket(Member $member): bool
+    {
+        if ($member->user_id === null) {
+            return true;
+        }
+
+        return Member::query()
+            ->where('channel_id', $member->channel_id)
+            ->where('user_id', $member->user_id)
+            ->orderBy('created_at')
+            ->orderBy('id')
+            ->value('id') === $member->id;
+    }
+
     /**
      * @throws ExpiredException
      * @throws InvalidSocketException

src/Model/Member.php

@@ -13,6 +13,7 @@
  * @property-read string $id
  * @property-read string $channel_id
  * @property-read string $socket_id
+ * @property-read string|null $user_id
  * @property-read mixed[] $data
  */
 class Member extends Model
@@ -33,12 +34,13 @@ class Member extends Model
     protected $guarded = [];
 
     /** @var list<string> */
-    protected $fillable = ['channel_id', 'socket_id', 'data'];
+    protected $fillable = ['channel_id', 'socket_id', 'user_id', 'data'];
 
     /** @var array<string, string> */
     protected $casts = [
         'channel_id' => 'string',
         'socket_id'  => 'string',
+        'user_id'    => 'string',
         'data'       => 'json',
     ];
 

tests/Unit/SocketTest.php

@@ -7,6 +7,7 @@
 use SupportPal\Pollcast\Exception\InvalidSocketException;
 use SupportPal\Pollcast\Model\Channel;
 use SupportPal\Pollcast\Model\Member;
+use SupportPal\Pollcast\Model\Message;
 use SupportPal\Pollcast\Tests\TestCase;
 
 use function app;
@@ -134,6 +135,7 @@ public function testJoinPresenceChannel(): void
         $this->assertDatabaseHas('pollcast_channel_members', [
             'channel_id' => $channel->id,
             'socket_id'  => $socketId,
+            'user_id'    => '1',
             'data'       => json_encode($data),
         ]);
 
@@ -156,6 +158,42 @@ public function testJoinPresenceChannel(): void
         ]);
     }
 
+    public function testJoinPresenceChannelWithAnotherSocketOfTheSameUser(): void
+    {
+        $socket = new Socket(app('config'), app('session.store'), request());
+        $socket->setId('test');
+
+        $data = ['user_id' => 1, 'user_info' => ['name' => 'Someone']];
+        $channel = Channel::factory()->create(['name' => 'presence-channel']);
+        Member::factory()->create(['channel_id' => $channel->id, 'socket_id' => 'other-tab', 'data' => $data, 'created_at' => now()->subMinute()]);
+        Member::factory()->create(['channel_id' => $channel->id, 'socket_id' => 'someone-else', 'data' => $other = ['user_id' => 2]]);
+
+        $socket->joinChannel($channel->name, $data);
+
+        $this->assertDatabaseHas('pollcast_message_queue', [
+            'channel_id' => $channel->id,
+            'event'      => 'pollcast:subscription_succeeded',
+            'payload'    => json_encode([$data, $other]),
+        ]);
+        $this->assertDatabaseMissing('pollcast_message_queue', ['event' => 'pollcast:member_added']);
+    }
+
+    public function testJoinPresenceChannelAtTheSameTimeAsAnotherSocketOfTheSameUser(): void
+    {
+        $data = ['user_id' => 1, 'user_info' => ['name' => 'Someone']];
+        $channel = Channel::factory()->create(['name' => 'presence-channel']);
+
+        // Both sockets' rows exist before either has checked for the other.
+        $tabA = Member::factory()->create(['channel_id' => $channel->id, 'socket_id' => 'tab-a', 'data' => $data]);
+        Member::factory()->create(['channel_id' => $channel->id, 'socket_id' => 'tab-b', 'data' => $data, 'created_at' => $tabA->created_at]);
+
+        foreach (['tab-a', 'tab-b'] as $socketId) {
+            (new Socket(app('config'), app('session.store'), request()))->setId($socketId)->joinChannel($channel->name, $data);
+        }
+
+        $this->assertSame(1, Message::query()->where('event', 'pollcast:member_added')->count());
+    }
+
     public function testRemoveMemberFromChannel(): void
     {
         $socketId = 'test';
@@ -198,6 +236,21 @@ public function testRemoveMemberFromPresenceChannel(): void
         ]);
     }
 
+    public function testRemoveMemberFromPresenceChannelWithAnotherSocketOfTheSameUser(): void
+    {
+        $socket = new Socket(app('config'), app('session.store'), request());
+
+        $data = ['user_id' => 1];
+        $channel = Channel::factory()->create(['name' => 'presence-name']);
+        $member = Member::factory()->create(['channel_id' => $channel->id, 'data' => $data]);
+        Member::factory()->create(['channel_id' => $channel->id, 'data' => $data]);
+
+        $socket->removeMemberFromChannel($member, $channel);
+
+        $this->assertDatabaseMissing('pollcast_channel_members', ['id' => $member->id]);
+        $this->assertDatabaseMissing('pollcast_message_queue', ['event' => 'pollcast:member_removed']);
+    }
+
     /**
      * A private channel is authorised like a presence one but publishes nothing about who is on
      * it, so a member leaving is not announced to the others.