Protocol

The HubProtocol interface defines the contract for protocols used by SignalRKore to serialize and deserialize messages sent between the client and the server. SignalRKore currently provides one implementation of this interface: JsonHubProtocol.

HubProtocol Interface

The HubProtocol interface defines the following properties and methods:

interface HubProtocol {
    val name: String
    val version: Int
    val transferFormat: TransferFormat

    fun parseMessages(payload: ByteArray): List<HubMessage>
    fun writeMessage(message: HubMessage): ByteArray
}

JsonHubProtocol

The JsonHubProtocol class is the default implementation of the HubProtocol interface. It uses JSON for serialization and deserialization of messages.

val connection = HubConnectionBuilder.create("https://example.com/chathub") {
    protocol = JsonHubProtocol()  // Default
}

Custom Protocol

You can implement your own protocol by implementing the HubProtocol interface. This is an advanced use case and is not typically needed.

class MyHubProtocol : HubProtocol {
    override val name: String = "my-protocol"
    override val version: Int = 1
    override val transferFormat: TransferFormat = TransferFormat.Text

    override fun parseMessages(payload: ByteArray): List<HubMessage> {
        // Your implementation
    }

    override fun writeMessage(message: HubMessage): ByteArray {
        // Your implementation
    }
}

val connection = HubConnectionBuilder.create("https://example.com/chathub") {
    protocol = MyHubProtocol()
}

HubMessage

The HubMessage sealed class represents messages sent between the client and the server. It has several subclasses for different types of messages:

• HubMessage.Invocation: Represents an invocation of a hub method
• HubMessage.StreamInvocation: Represents an invocation of a streaming hub method
• HubMessage.StreamItem: Represents an item in a stream
• HubMessage.Completion: Represents the completion of a hub method invocation
• HubMessage.Ping: Represents a ping message
• HubMessage.Close: Represents a close message
• HubMessage.CancelInvocation: Represents a cancellation of a streaming hub method invocation

TransferFormat

The TransferFormat enum defines the format in which messages are transferred:

enum class TransferFormat {
    Text,
    Binary
}

API Reference

HubProtocol Interface

Properties

Name	Type	Description
name	String	The name of the protocol
version	Int	The version of the protocol
transferFormat	TransferFormat	The format in which messages are transferred

Methods

Name	Parameters	Return Type	Description
parseMessages	payload: ByteArray	List<HubMessage>	Parses messages from a byte array
writeMessage	message: HubMessage	ByteArray	Writes a message to a byte array

JsonHubProtocol

The JsonHubProtocol class is the default implementation of the HubProtocol interface. It uses JSON for serialization and deserialization of messages.

Properties

Name	Type	Value	Description
name	String	"json"	The name of the protocol
version	Int	1	The version of the protocol
transferFormat	TransferFormat	TransferFormat.Text	The format in which messages are transferred

TransferFormat

Value	Description
Text	Messages are transferred as text
Binary	Messages are transferred as binary data

Implementation Details

The JsonHubProtocol class uses Kotlinx Serialization for JSON serialization and deserialization. It handles the following message types:

• Invocation
• StreamInvocation
• StreamItem
• Completion
• Ping
• Close
• CancelInvocation

Each message type has a specific format defined by the SignalR protocol. The JsonHubProtocol class handles the serialization and deserialization of these messages according to the protocol specification.

For more details on the SignalR protocol, see the official documentation.