supabase / supabase-flutter / 32480403815

89%

Build Type

push

github

Committed by web-flow

Commit Message

feat(realtime)!: support asynchronous encode/decode codecs (#1684)

Closes #1401

## What

The realtime codec overrides (`RealtimeEncode` / `RealtimeDecode`, added
in #1397) were synchronous and worked on raw `Map<String, dynamic>`s, so
`jsonEncode`/`jsonDecode` of every message ran on the main isolate. A
large payload blocks the event loop, and a background-isolate codec
could not be plugged in at all.

Both typedefs now work on a `RealtimeMessage` and return a `Future`:

| Before | After |
| --- | --- |
| `Object Function(Map<String, dynamic>)` | `Future<Object>
Function(RealtimeMessage)` |
| `Map<String, dynamic> Function(Object)` | `Future<RealtimeMessage>
Function(Object)` |

```dart
final isolate = YAJsonIsolate();

await Supabase.initialize(
  url: url,
  anonKey: anonKey,
  realtimeClientOptions: RealtimeClientOptions(
    encode: (message) => isolate.encode(message.toJson()),
    decode: (frame) async =>
        RealtimeMessage.fromJson(await isolate.decode(frame as String)),
  ),
);
```

`RealtimeClientOptions` carries the two callbacks through
`SupabaseClient` and `Supabase.initialize`, so a `supabase_flutter` user
never has to construct a `RealtimeClient` by hand.

## `RealtimeMessage`

A new exported class carrying `joinRef`, `ref`, `topic`, `event` and
`payload`, with `toJson([version])` and `RealtimeMessage.fromJson(json,
[version])` converting to and from the shape each protocol version puts
on the wire (positional array for `2.0.0`, object for `1.0.0`, both
defaulting to `2.0.0`). A codec only has to turn that shape into bytes
and back rather than hand-building the positional array.

It replaces the internal `Message` class. An `@internal`
`RealtimeMessage.outgoing` builds one from a `ChannelEvent` and replaces
`Binding`s in the payload with their serializable shape, which matters
more now: a `Binding` holds a callback and could never be sent to an
isolate.

## Ordering

Introducing awaits into the message pipeline is the risky part, ... (continued)

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