Pass input to a worker

WorkInput is a typed key/value bag, capped at 10 240 bytes when serialised — the same hard cap as Android's androidx.work.Data. The cap is enforced cross-platform so you can't accidentally write input that survives Android-only-or-iOS-only.

val input = WorkInput.of(
    "imageUri" to WorkValue.StringValue("file:///path/to/image.jpg"),
    "quality" to WorkValue.LongValue(85L),
    "thumbnail" to WorkValue.BooleanValue(true),
)

backgrounder.scheduler.schedule(
    WorkRequest.OneTime(
        taskId = ProcessImageWorker.ID,
        input = input,
    ),
)

Inside the worker:

override suspend fun execute(context: WorkerContext): WorkResult {
    val uri = (context.input["imageUri"] as? WorkValue.StringValue)?.value
        ?: return WorkResult.Failure("missing imageUri")
    val quality = (context.input["quality"] as? WorkValue.LongValue)?.value ?: 75L
    // ...
}

Supported value types

WorkValue is sealed:

• StringValue(String)
• LongValue(Long)
• DoubleValue(Double)
• BooleanValue(Boolean)
• BytesValue(ByteArray)

This is the intersection of androidx.work.Data's primitive set and what serialises cleanly to JSON for iOS / macOS persistence. Int is intentionally absent — use Long. Nested objects are intentionally absent — flatten or serialise to a string.

Why JSON for the wire format

On Android, the whole WorkInput is JSON-encoded into a single Data string key (rather than projecting each WorkValue onto a Data primitive). Reasons:

1. Data's primitive set is narrower than WorkValue's on some Android versions.
2. The size cap is enforced at WorkInput.of() time using the same serializer, so we don't risk "fits one shape, doesn't fit the other."
3. iOS / macOS persist input the same way (in the library state store), so the wire format is uniform across platforms.

Sizing

WorkInput.of("payload" to WorkValue.StringValue("x".repeat(20_000)))
// → throws IllegalArgumentException: WorkInput exceeds the 10240-byte cap

If you legitimately need to pass more than 10 KB to a worker, store the payload yourself (your DB, a temp file) and pass an opaque key in the input.