> For the complete documentation index, see [llms.txt](https://docs.marioded.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.marioded.com/api-how-to-guides/availability.md).

# Availability and dispatch

Send an authorized viewer to a replay server and understand what dispatch completion means.

**Runtime:** lobby · **Entry point:** `ReverseLobby` · **Watch calls:** Bukkit main thread

## Prefer the high-level lobby service

If a player selects a replay in your lobby UI, call:

```java
ReverseLobby lobby = ReverseLobby.get().orElseThrow();
lobby.getDispatchService().watch(viewer, replayId)
    .whenComplete((result, failure) -> {
        if (failure != null) {
            plugin.getLogger().log(Level.WARNING, "Could not dispatch viewer", failure);
        } else {
            plugin.getLogger().info("Replay dispatch result: " + result);
        }
    });
```

Here `plugin` is our integration's JavaPlugin, `viewer` is the requesting player, and `replayId` is their selection. Invoke this from the main thread. The service performs the lobby-policy access check and handoff sequence; the callback above only logs the result.

Call on the main thread. The returned stage can complete on a backend thread. Handle an exceptional completion in addition to the result enum:

| Result            | Meaning                                                                      |
| ----------------- | ---------------------------------------------------------------------------- |
| `SUCCESS`         | Pending playback persisted and proxy transfer message sent.                  |
| `NOT_AUTHORIZED`  | Missing replay or actor not allowed to view it.                              |
| `NO_REPLAYER`     | No fresh player-node heartbeat.                                              |
| `TRANSFER_FAILED` | Request could not complete, including an overlapping request by that viewer. |

The service uses the lobby's current access policy and guards duplicate in-flight requests. Do not bypass that with raw pending-selection writes merely to hide an authorization failure.

{% hint style="info" %}
**Dispatch success means “handoff sent.”** It does not confirm that the proxy connected the viewer or playback started. Observe the target runtime's start event when you need that acknowledgment.
{% endhint %}

## What availability stores

`Availability` represents:

* `heartbeat(nodeId)` and `leave(nodeId)` for node liveness.
* `active()` for fresh nodes, ordered oldest heartbeat first.
* `pending(nodeId, viewerId, PendingPlayback)` to store a short-lived selection.
* `take(nodeId, viewerId)` to consume that selection once.

`PendingPlayback` contains the replay ID and origin server. Selections expire after five minutes. This contract does not expose reservations, queue position, capacity, match status, or playback progress.

## SQL and Redis

Factories supply concrete availability backends. `AvailabilityService` registers factories, opens the configured backend, manages node heartbeat/start lifecycle, and closes owned resources. Database availability depends on an opened SQL storage resource; Redis is independently configured and lazily loads its runtime libraries.

A facade may return null from `getAvailability()` when networking is disabled. Ordinary plugins should borrow that configured backend rather than closing it or starting a second heartbeat loop over the same runtime instance.

The public entry points do not automatically discover arbitrary external availability factories. Use the configured backend for normal lobby integrations; check the supported extension hooks before attempting to introduce a new backend.

## Transfer is not confirmation

The transfer implementation sends a `Connect` message over the BungeeCord channel. Dispatch success does not confirm arrival. The target player runtime consumes a selection when the viewer joins and then loads the replay. Expiry, proxy errors, disconnection, or storage failure can prevent playback after dispatch was accepted.

If your application needs a guaranteed “viewer is now watching” signal, observe `PlaybackStartEvent` on the target runtime and communicate it through your own application channel. Do not reinterpret `SUCCESS` as that acknowledgment.

## Integrating a custom lobby menu

Use the catalog to display accessible metadata and the dispatch service for Watch. The shared `MenuActionRegistry` lets you attach custom actions without importing Inventory Framework. Obtain it from `ReverseLobby`, not from a new registry instance that the real menu never uses.

For a purely local viewing integration, use `ReversePlayer` instead. Availability is unnecessary when no cross-server transfer is involved.

{% content-ref url="/pages/sw2rn3Xw68PPxoBh1DT1" %}
[Lobby and proxy setup](/use-reverse/network.md)
{% endcontent-ref %}


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