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At-least-once message delivery for Resonate channels. Every broadcast is logged to a per-channel Redis Stream; a reconnecting client sends the id of the last message it saw, and the plugin replays everything since before live delivery resumes.

Solves the single most common WebSocket complaint: "I dropped for 20 seconds and missed messages."

What you get

A Laravel broadcaster (resonate-delivery driver) that wraps Reverb, logs every broadcast, and tags the payload with a monotonic _replay_id.
A Resonate server plugin that, when a subscribe carries last_event_id, replays the missed messages on that channel after subscription_succeeded and before any live broadcast.
Bounded retention via Redis Streams MAXLEN ~ N, configurable per-channel.

What this is (and isn't)

At-least-once within retention. With the default cap of 1000 messages per channel, a client that drops for 5 minutes on a low-traffic channel reconnects seamlessly. A client offline for hours on a high-traffic channel sees a clean break — design retention based on expected disconnect duration and your publish rate.
Duplicates can happen at the seam. A message published exactly as a reconnecting client is mid-replay may arrive both in the replay and as a live broadcast. Each message carries a monotonic _replay_id; the client deduplicates by it.
No ACK protocol. This is not a message queue. A subscriber that goes away forever does not hold a slot in any per-subscriber outbox. Per-subscriber state lives only on the connection.
Server broadcasts only in v0.1. client-* whispers between clients are not logged; they reach connected subscribers only.

Installation

composer require webpatser/resonate-delivery

Publish the config to set retention defaults or override the underlying broadcaster:

php artisan vendor:publish --tag=resonate-delivery-config

Configuring the broadcaster

Add the wrapping driver to config/broadcasting.php and point your default at it:

'default' => env('BROADCAST_DRIVER', 'resonate-delivery'),

'connections' => [
    // ... keep your existing 'reverb' connection as-is

    'resonate-delivery' => [
        'driver' => 'resonate-delivery',
        'underlying' => 'reverb',
    ],
],

The wrapper delegates auth and the actual WebSocket send to the underlying connection (so your existing Reverb setup is unchanged); it adds the log write and the _replay_id augmentation around it.

Registering the server plugin

In config/reverb.php, list the plugin alongside any others you have running:

'plugins' => [
    \Webpatser\ResonateDelivery\MessageReplayPlugin::class,
],

Restart Resonate (resonate:reload for a zero-downtime swap).

Client protocol

A client that wants replay sends last_event_id in the subscribe payload:

{"event": "pusher:subscribe",
 "data": {"channel": "presence-chat.42", "auth": "...", "last_event_id": "1700000000000-0"}}

On every message it receives, the client reads data._replay_id and remembers the highest. On reconnect, it sends that value. First-time subscribers omit the field and get no replay (normal Pusher behaviour).

For Laravel Echo and the JS Pusher client there is no built-in plug for this; consumers must subscribe with the custom data field, which both libraries support via their lower-level subscription APIs.

Configuration reference

Key	Default	Purpose
`connection`	`REDIS_*` env	Redis server hosting the streams. The broadcaster (predis) and the plugin (fledge async) must point at the same server/database.
`key_prefix`	`delivery`	Namespace for stream keys (`{prefix}:{appId}:{channel}`).
`retention.default_max_messages`	`1000`	Default per-channel cap.
`retention.per_channel`	`[]`	fnmatch glob => max messages overrides.
`replay_id_field`	`_replay_id`	The `data` key that carries each message's stream id.
`underlying`	`reverb`	Name of the broadcaster the wrapper delegates to.
`replay_batch_size`	`100`	XRANGE page size during replay.

Requirements

PHP 8.5+
Laravel 13
Resonate 0.4+
Redis 5+ (Redis Streams; included in any modern Redis)

Testing

composer test

Tests that touch Redis expect a server on 127.0.0.1:6379 and use database 15; they skip cleanly when no Redis is reachable.

License

MIT. See LICENSE.

webpatser / resonate-delivery

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