Live events (SSE)

MeroKit streams a node’s real-time context events over Server-Sent Events. The task-oriented walkthrough is the live events guide; this page is the API surface.

`mero.events(contextIds:groupIds:)`

nonisolated func events(
    contextIds: [String], groupIds: [String] = []
) -> AsyncThrowingStream<ContextEvent, Error>

Opens GET /sse (bearer token in the Authorization header) and subscribes to the given context and group ids via POST /sse/subscription, then yields a ContextEvent per emission. It is nonisolated — callable without await — and reconnects automatically ~3s after a drop (the node persists session subscriptions). Consume it with for try await; cancel the enclosing Task to close the connection.

let task = Task {
    for try await event in mero.events(contextIds: [contextId]) {
        print(event.contextId, event.kind)
        await reload()
    }
}
// later:
task.cancel()   // closes the SSE stream

`ContextEvent`

public struct ContextEvent: Sendable {
    public let contextId: String   // "" for a group-keyed event
    public let kind: String        // "StateMutation", "SyncStatus", "Ephemeral", "MemberJoined", ...
    public let payload: JSONValue  // raw event JSON
    public let groupId: String?    // set for a group-keyed event (core rc.83)

    public var presenceAccount: String? { get }  // Ephemeral: the relayed account (rc.83)
    public var presenceAuthor: String? { get }   // Ephemeral: the author's signing key
}

Group events (core rc.83). Pass groupIds to also receive group-keyed events: membership (MemberJoined, MemberAdded, MemberRemoved, carrying memberAccount and maybe role) and migration (MigrationStarted, MigrationProgress, CascadeProgress, MigrationCompleted). They arrive with groupId set. groupIds is sent only when non-empty, so a context-only subscription is the same body an older node accepts. A client key can only subscribe to the contexts and groups it is bound to.

Presence. An Ephemeral event’s data.account names the account behind a presence update a relay carried; presenceAccount reads it.

For a state change (kind == "StateMutation") the encoded contract events live under payload’s data.events[].data.

`SseClient`

mero.events(...) builds an SseClient for you; use it directly only if you need to manage the connection yourself.

public final class SseClient: @unchecked Sendable {
    public init(
        baseURL: URL,
        token: @escaping @Sendable () async -> String?,
        session: URLSession = .shared
    )
    public func events(
        contextIds: [String], groupIds: [String] = []
    ) -> AsyncThrowingStream<ContextEvent, Error>
}