Struct SubscriptionRegistry 

pub struct SubscriptionRegistry { /* private fields */ }

Per-URI registry of subscribed peers with broadcast helpers.

Cheap to clone (all state is behind an Arc<Mutex<...>> externally — typically Arc<SubscriptionRegistry> on the server). Methods take &self because the internal Mutex provides interior mutability.

Implementations

impl SubscriptionRegistry

pub fn new() -> Self

Build an empty registry.

pub fn subscribe(&self, uri: &str, peer: Peer<RoleServer>)

Record a new subscription. See the module-level docs for the duplicate-subscribe behaviour: two calls with the same peer land two entries in the list.

pub fn unsubscribe(&self, uri: &str, _peer: &Peer<RoleServer>) -> usize

Remove all subscriptions for uri. Returns the number of entries that were removed.

_peer is accepted for API symmetry with the MCP protocol (the incoming unsubscribe request carries no peer identity beyond “the session issuing the call”), but isn’t used for matching.

pub fn subscribers_for(&self, uri: &str) -> Vec<Peer<RoleServer>>

Return a snapshot of all peers subscribed to uri. Useful for tests and for the notify helpers below, which want to release the mutex before doing any async work.

pub fn subscribed_uris(&self) -> Vec<String>

Return the set of URIs that currently have at least one subscriber.

pub fn clear(&self)

Drop all subscriptions for every URI. Invoked when the server is shutting down or a full workspace reset has happened.

pub fn notify_updated(&self, uri: &str)

Fire a notifications/resources/updated for uri to every current subscriber. Sends happen in detached tokio tasks so the caller doesn’t wait on the channel.

If a send fails (typically because the peer disconnected) we log the error at debug level but do not prune the dead peer — see the module-level “Tradeoffs” note for why. Over very long-lived servers this can accumulate stale entries in the registry.

No-op when the caller is outside a tokio runtime or the registry has no subscribers for uri.

pub fn notify_list_changed(&self)

Fire a notifications/resources/list_changed broadcast to every subscribed peer (across all URIs). Called when tables are added or dropped, or saved queries created / deleted.

Deduplicates peers across URIs so a client subscribed to three URIs only receives one list-changed notification.

Trait Implementations

impl Debug for SubscriptionRegistry

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for SubscriptionRegistry

fn default() -> SubscriptionRegistry

Returns the “default value” for a type.