added presence api update

[ArnabChatterjee20k]

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[greptile-apps]

Greptile Summary

This PR adds a createPresence API to the Realtime service across all SDK templates (Flutter, Android, Apple, Web), backed by a new WebSocket mock server that handles the presence message type. It also makes the additional-properties field name configurable via the x-additional-properties-key OpenAPI extension, replacing the hardcoded data field across every model template.

• createPresence implementation: Each platform adds a FIFO queue of in-flight presence requests correlated to server responses via the ordered single WebSocket connection; handleResponseError correctly drains the queue on server-error frames.
• additionalPropertiesKey templating: Swagger2.php extracts x-additional-properties-key (default 'data') and all model templates propagate it, maintaining backward compatibility for models that don't set the extension.
• Flutter test reliability: subscribeTo defers _createSocket() via Future.delayed(Duration.zero, ...), so _websok is still null when createPresenceTo immediately checks it \u2014 the presence test will always fall into its catch block and report \"Realtime presence:failed\".

Confidence Score: 3/5

Not safe to merge without fixing the Flutter test (always fails) and the unresolved socket-close handling gaps across all four platforms.

The Flutter presence test is structurally broken: subscribe schedules WebSocket creation asynchronously, so _websok is always null when createPresence is called on the next line, causing an immediate throw and a permanent "Realtime presence:failed". Additionally, connection-drop paths (onDone/onError in Flutter, onClosing/onFailure in Android, onClose/onError delegates in Swift, close event and disconnect() in Web) all skip draining in-flight presence requests, leaving callers permanently suspended.

tests/languages/flutter/tests.dart (always-failing presence test), and the four Realtime service templates for socket-close handling of pending presence requests.

Important Files Changed

Filename	Overview
mock-server/src/Utopia/Realtime/Protocol.php	New file: implements authentication, subscribe, unsubscribe, presence, and ping handlers for the mock WebSocket server; protocol shapes match what SDKs expect.
src/Spec/Swagger2.php	Adds additionalPropertiesKey (sourced from x-additional-properties-key, default 'data') to model definitions, enabling configurable additional-properties field names across all SDK templates.
templates/flutter/lib/src/realtime_mixin.dart.twig	Adds createPresenceTo and FIFO presence-response correlation; handleError drains pending presence requests, but onDone/onError WebSocket stream callbacks still do not drain _pendingPresenceRequests.
templates/android/library/src/main/java/io/package/services/Realtime.kt.twig	Adds createPresence suspend function with FIFO deferred queue; handleResponseError drains pending requests on error, but onClosing/onFailure socket callbacks do not drain pendingPresenceRequests.
templates/apple/Sources/Services/Realtime.swift.twig	Adds createPresence async/throws with CheckedContinuation queue; handleResponseError drains pending continuations, but onClose/onError delegate callbacks do not resume pending continuations.
templates/web/src/services/realtime.ts.twig	Adds createPresence returning a Promise; handleError drains pending requests, but the close socket event and disconnect() still do not drain pendingPresenceRequests.
tests/languages/flutter/tests.dart	Adds presence test; the test always reports failure because subscribe schedules socket creation asynchronously and createPresence runs before _websok is set.

Comments Outside Diff (1)

1. tests/languages/flutter/tests.dart, line 1477-1483 (link)

   Flutter presence test always fails — _websok is null when createPresence is called

   subscribeTo (called by subscribe) schedules _createSocket() via Future.delayed(Duration.zero, ...), so the WebSocket factory hasn't run yet when execution reaches await createPresence(...). createPresenceTo checks if (ws == null …) synchronously — _websok is still null — and throws immediately, so the catch block always prints "Realtime presence:failed".

   The fix is to await something that guarantees the socket is open before calling createPresence. A small Future.delayed(Duration.zero) trampoline after subscribe (to let the event loop fire _createSocket) is the minimal change; ideally the subscribe API itself should expose a "connected" signal.

_{Reviews (3): Last reviewed commit: "added presence api tests and mock server" | Re-trigger Greptile}

[greptile-apps]

Missing newline at end of file

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