Wire Protocol

SignalARRR communicates over standard SignalR using a fixed set of hub methods. This page documents the protocol for advanced use cases and custom client implementations.

Hub method names

Client → Server

Hub method	Purpose	Payload	Returns
InvokeMessage	Fire-and-forget (void methods)	ClientRequestMessage	—
InvokeMessageResult	Call with return value	ClientRequestMessage	object
SendMessage	Fire-and-forget (Task methods)	ClientRequestMessage	—
StreamMessage	Open a server-to-client stream	ClientRequestMessage	IAsyncEnumerable<object>
StreamItemToServer	Send a stream item	Guid streamId, object item	—
StreamCompleteToServer	Complete a stream	Guid streamId, string? error	—

Server → Client

Message	Purpose	Payload
InvokeServerRequest	Call client method, expect reply (native client result)	ServerRequestMessage
InvokeServerMessage	Call client method, fire-and-forget	ServerRequestMessage
ChallengeAuthentication	Request fresh auth token	ServerRequestMessage
CancelTokenFromServer	Cancel a client operation	ServerRequestMessage (with CancellationGuid)

Message types

ClientRequestMessage

Sent from client to server with every RPC call.

{
    "Method": "ChatMethods.SendMessage",
    "Arguments": ["Alice", "Hello!"],
    "Authorization": "Bearer eyJ...",
    "GenericArguments": []
}

Field	Type	Required	Description
Method	string	Yes	ClassName.MethodName or InterfaceName|MethodName
Arguments	array	Yes	Serialized method arguments
Authorization	string	No	Bearer token for authenticated methods
GenericArguments	string[]	No	Type names for generic methods

ServerRequestMessage

Sent from server to client for bidirectional RPC.

{
    "Id": "550e8400-e29b-41d4-a716-446655440000",
    "Method": "GetClientName",
    "Arguments": [],
    "CancellationGuid": null,
    "StreamId": null
}

Field	Type	Required	Description
Id	GUID	Yes	Correlation ID — used internally by SignalR's native client results
Method	string	Yes	Method name to invoke on client
Arguments	array	No	Method arguments
GenericArguments	string[]	No	Generic type arguments
CancellationGuid	GUID	No	Links to CancelTokenFromServer for remote cancellation
StreamId	GUID	No	Stream correlation for client-to-server streams

CancellationTokenReference

Marker object placed in Arguments where a CancellationToken parameter exists. The client detects this and substitutes an AbortSignal (TypeScript) or CancellationToken (.NET).

{
    "Id": "550e8400-e29b-41d4-a716-446655440001"
}

Protocol flows

Client calls server (with result)

Server calls client (with result)

Token challenge flow

Client-to-server streaming

Method name resolution

The server resolves method names in two formats:

Format	Example	Resolution
ClassName.MethodName	ChatMethods.SendMessage	Direct lookup in method collection
InterfaceName|MethodName	IChatHub|SendMessage	Interface-based lookup (used by typed proxies)

Next steps

• API Overview — public API surface
• Packages — package guide
• Cancellation Propagation — cancellation protocol