Collect & Inject Values Requests

Maryk allows values from one response to be injected into another request. You can request an object, collect specific values from the response and use them in a follow‑up request on the same or a different data model.

This approach avoids multiple round trips between client and datastore by bundling related operations into a single request.

Combining several requests in one reduces latency and improves overall throughput.

The example below collects and injects values to fetch the friends of two people.

Example: Fetching all data of the Friends of Two Persons

val context = RequestContext(definitionsContext)
val requests = Requests.create(context = context) {
    this.requests -= listOf(
        RequestType.Collect(
            CollectRequest(
                "collectedResponse",
                Person.get(
                    Person.key("dR9gVdRcSPw2molM1AiOng"),
                    Person.key("Vc4WgX/mQHYCSEoLtfLSUQ")
                )
            )
        ),
        RequestType.Get(
            // Injected requests stay as ObjectValues until the collected result is available.
            GetRequest.create(context = context) {
                from with Person
                keys with Inject(
                    "collectedResponse",
                    ValuesResponse {
                        values.atAny { values.withModel(Person) { friends } }
                    }
                )
            }
        )
    )
}

val responses = remote.execute(requests)

Within the batch, CollectRequest fetches two people and stores the response as collectedResponse.

The following GetRequest fetches their friends. Inject pulls the friend references from collectedResponse and injects them into the new request.

Batch responses are returned in request order. Execution stops at the first failure. The batch is not transactionally atomic: writes completed before a later failure remain committed.

Conclusion

Collect & Inject enables dynamic request workflows by consolidating related queries, reducing round trips and speeding up data retrieval.