Struct NotificationHandler 

pub struct NotificationHandler { /* private fields */ }

Callback-based handler for server notifications.

Provides typed callback registration for each notification type, without requiring a full ClientHandler trait implementation. Server-initiated requests (sampling, elicitation, roots) are rejected with method_not_found.

Example

use tower_mcp::client::NotificationHandler;

let handler = NotificationHandler::new()
    .on_progress(|p| {
        println!("Progress: {}/{}", p.progress, p.total.unwrap_or(1.0));
    })
    .on_tools_changed(|| {
        println!("Server tools changed!");
    });

Implementations

impl NotificationHandler

pub fn new() -> Self

Create a new handler with no callbacks registered.

pub fn with_log_forwarding() -> Self

Create a handler that forwards MCP log messages to tracing.

Maps MCP log levels to tracing levels:

• Emergency, Alert, Critical -> error!
• Error -> error!
• Warning -> warn!
• Notice, Info -> info!
• Debug -> debug!

pub fn on_progress( self, f: impl Fn(ProgressParams) + Send + Sync + 'static, ) -> Self

Register a callback for progress notifications.

pub fn on_log_message( self, f: impl Fn(LoggingMessageParams) + Send + Sync + 'static, ) -> Self

Register a callback for log message notifications.

pub fn on_resource_updated( self, f: impl Fn(String) + Send + Sync + 'static, ) -> Self

Register a callback for resource updated notifications.

The callback receives the URI of the updated resource.

pub fn on_resources_changed(self, f: impl Fn() + Send + Sync + 'static) -> Self

Register a callback for resources list changed notifications.

pub fn on_tools_changed(self, f: impl Fn() + Send + Sync + 'static) -> Self

Register a callback for tools list changed notifications.

pub fn on_prompts_changed(self, f: impl Fn() + Send + Sync + 'static) -> Self

Register a callback for prompts list changed notifications.

Trait Implementations

impl ClientHandler for NotificationHandler

fn on_notification<'life0, 'async_trait>( &'life0 self, notification: ServerNotification, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Called when the server sends a notification.

fn handle_create_message<'life0, 'async_trait>( &'life0 self, _params: CreateMessageParams, ) -> Pin<Box<dyn Future<Output = Result<CreateMessageResult, JsonRpcError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Handle a sampling/createMessage request from the server.

fn handle_elicit<'life0, 'async_trait>( &'life0 self, _params: ElicitRequestParams, ) -> Pin<Box<dyn Future<Output = Result<ElicitResult, JsonRpcError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Handle an elicitation/create request from the server.

fn handle_list_roots<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<ListRootsResult, JsonRpcError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Handle a roots/list request from the server.

impl Debug for NotificationHandler

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

Formats the value using the given formatter.

impl Default for NotificationHandler

fn default() -> Self

Returns the “default value” for a type.