#Proton Client

justjavac/proton_client invokes typed Proton contracts from the active renderer page. It uses the bridge installed by Proton before application scripts run; applications do not construct a client or select a transport.

///|
async fn load_todos {
  let snapshot = @proton_client.invoke(@shared.list_todos, {})
  render(snapshot)
}

Requests are encoded and responses are decoded at the client boundary. Transport, timeout, cancellation, remote execution, and decoding failures are raised as ClientFailure.

#
ClientFailure

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pub(all) suberror ClientFailure {
  BridgeUnavailable
  RequestCancelled
  RequestTimedOut
  InvalidContract(message~ : String)
  RemoteFailure(code~ : String, message~ : String, detail~ : String?)
  TransportFailure(message~ : String)
  ResponseDecode(message~ : String)
  EventDecode(message~ : String)
} derive(Eq, @moonbitlang/core/debug.Debug
Debug)

Failures raised by the typed frontend client.

#
ClientFailure::message

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fn ClientFailure::message(self : ClientFailure) -> String

Returns a user-facing description of this client failure.

#
Subscription

source

pub struct Subscription {
  closed : Bool
  close_listener : () -> Unit
}

A live event subscription installed on the active renderer page.

#
Subscription::close

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fn Subscription::close(self : Subscription) -> Unit

Removes this subscription. Repeated calls have no effect.

#
invoke

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async fn[Request : ToJson, Response : @moonbitlang/core/json.FromJson
FromJson] invoke(command : @justjavac/proton_contract.Command
Command[Request, Response], request : Request) -> Response raise ClientFailure

Invokes a typed command through the bridge installed on the active page.

fn[Payload : @moonbitlang/core/json.FromJson
FromJson] subscribe(event : @justjavac/proton_contract.Event
Event[Payload], received : (Payload) -> Unit, failure : (ClientFailure) -> Unit) -> Subscription raise ClientFailure