Unreal SDK: no way to set confirmed reads on the connection (Rust SDK has with_confirmed_reads)

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
84/100
Issue type
Feature
Clarity
Clearly specified
Activity status
Active
Tech stack
cpp, unreal-engine
Domain
game-dev, networking

Research direction

Start with UDbConnectionBuilderBase::Build in sdks/unreal/src/SpacetimeDbSdk/Private/Connection/DbConnectionBuilder.cpp, using the Rust implementation in sdks/rust/src/websocket.rs and db_connection.rs as the behavioral reference. Add the option to both the C++ and Blueprint-facing builders, preserving omission when unset and serializing an explicit boolean when configured. Done means confirmed=true or confirmed=false is appended correctly and covered by the relevant Unreal SDK tests.

Written by the indexing model from the issue text.

Description

SpacetimeDB 2.12.0, Unreal SDK from sdks/unreal/src/SpacetimeDbSdk at v2.12.0, UE 5.8.3.

The Rust SDK lets the client choose the read mode explicitly: DbConnectionBuilder::with_confirmed_reads(bool) adds &confirmed=true|false to the subscribe URL (sdks/rust/src/websocket.rs, db_connection.rs). The Unreal SDK has no equivalent: UDbConnectionBuilderBase::Build (Private/Connection/DbConnectionBuilder.cpp) always builds

<uri>/v1/database/<name>/subscribe?compression=<Gzip|None>

so the mode is whatever the server default is for the protocol. With v2.bsatn.spacetimedb (which the Unreal SDK uses, Websocket.cpp) the server default is confirmed = true (client-api/src/routes/subscribe.rs, DEFAULT_CONFIRMED_READS), which is what we want, but we can't pin it from the client.

Why it matters for us: our game logic treats "reducer reply received" as "the transaction is durable" (inventory, trades, store purchases are only shown as done after the reply). If the default ever changes, or a different protocol version is negotiated, Unreal clients would silently switch to replies-before-fsync, while our Rust tools keep true explicitly.

Request: add WithConfirmedReads(bool) to UDbConnectionBuilder (and the Blueprint builder), appending &confirmed=true|false only when it was set, mirroring the Rust SDK. We can send a PR if that helps.

Workaround today: none without patching the SDK (the database name is interpolated into the path, so a query parameter can't be injected cleanly). We rely on the v2 default and check it in our load tests.

Dominant language
Rust
Stars
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Forks
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Avg merge
3d 5h
Merged PRs (30d)
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