Struct ProxyHandler 

pub struct ProxyHandler { /* private fields */ }

A proxy handler that forwards requests to a client based on the server’s capabilities

Isolation:

• BackendIsolation::Shared: one backend, clones share Arcs (stdio).
• BackendIsolation::PerSession: factory creates a disconnected handler; backend is opened during initialize (so capabilities are real) and dropped with the session.

Implementations

impl ProxyHandler

pub fn swap_backend_from_connection(&self, conn: Option<StreamClientConnection>)

Update the backend from a high-level client connection.

impl ProxyHandler

pub fn upstream_peers(&self) -> Arc<UpstreamPeerRegistry>

Shared upstream peer registry used across reconnects.

pub fn new_disconnected( mcp_id: String, tool_filter: ToolFilter, default_info: ServerInfo, ) -> Self

创建断开状态的 handler（用于初始化） 后续通过 swap_backend() 注入实际的后端连接

pub fn new_disconnected_with_fallback( mcp_id: String, tool_filter: ToolFilter, default_info: ServerInfo, fallback_tools: Option<ListToolsResult>, ) -> Self

pub fn new_per_session( connector: Arc<dyn BackendConnector>, mcp_id: String, tool_filter: ToolFilter, ) -> Self

Create a disconnected per-session handler (URL isolation).

Backend is opened during ServerHandler::initialize so the initialize response carries real backend capabilities.

pub fn isolation(&self) -> BackendIsolation

Isolation mode for this handler.

pub fn new(client: BackendRunningService) -> Self

pub fn with_mcp_id(client: BackendRunningService, mcp_id: String) -> Self

pub fn with_tool_filter( client: BackendRunningService, mcp_id: String, tool_filter: ToolFilter, ) -> Self

创建带工具过滤器的 ProxyHandler（带初始后端连接，shared 隔离）

pub fn swap_backend(&self, new_client: Option<BackendRunningService>)

原子性替换后端连接

• Some(client): 设置新的后端连接
• None: 标记后端断开

版本控制：每次调用都会递增 backend_version，使旧 session 失效

注意：

• 新 client 应使用与本 handler 相同的 UpstreamPeerRegistry （见 StreamClientConnection::connect_with_peers）。
• 对 BackendIsolation::PerSession 的 management stub（builder 返回值） 调用此方法没有运维意义：真实后端由各 session handler 持有。

pub fn swap_backend_with_discovery( &self, new_client: Option<BackendRunningService>, complete_tools: Option<ListToolsResult>, )

pub fn is_backend_available(&self) -> bool

检查后端是否可用（快速检查，不发送请求）

pub async fn is_mcp_server_ready(&self) -> bool

检查 mcp 服务是否正常（异步版本，会发送验证请求）

pub fn is_terminated(&self) -> bool

检查后端连接是否已关闭（同步版本，仅检查 transport 状态）

pub async fn is_terminated_async(&self) -> bool

异步检查后端连接是否已断开（会发送验证请求）

pub fn mcp_id(&self) -> &str

获取 MCP ID

pub fn get_server_info_json(&self) -> Value

获取后端 ServerInfo 的 JSON 表示

用于跨 rmcp 版本桥接：将 rmcp 1.4.0 的 ServerInfo 序列化为 JSON， 供 rmcp 0.10 侧反序列化使用。

pub fn get_backend_version(&self) -> u64

获取当前后端版本号

版本号用于跟踪后端连接变化：

• 0: 断开状态
• 1+: 已连接，每次 swap_backend 递增

用途：配合 ProxyAwareSessionManager 实现 session 版本控制

impl ProxyHandler

pub async fn call_peer_method( &self, method: &str, params: Value, ) -> Result<Value, String>

Call a backend method through the version-independent JSON bridge.

Trait Implementations

impl BackendBridge for ProxyHandler

fn mcp_id(&self) -> &str

Get the MCP service identifier (used for logging and tracking)

fn get_server_info_json(&self) -> Value

Get the backend’s ServerInfo as JSON

fn is_backend_available(&self) -> bool

Check if the backend connection is available (fast, synchronous check)

fn is_mcp_server_ready(&self) -> Pin<Box<dyn Future<Output = bool> + Send + '_>>

Check if the MCP server is ready (async, sends a validation request)

fn is_terminated_async(&self) -> Pin<Box<dyn Future<Output = bool> + Send + '_>>

Check if the backend connection is terminated (async)

fn call_peer_method( &self, method: &str, params: Value, ) -> Pin<Box<dyn Future<Output = Result<Value, String>> + Send + '_>>

Call an MCP method on the backend via JSON bridge

impl Clone for ProxyHandler

fn clone(&self) -> ProxyHandler

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ProxyHandler

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

Formats the value using the given formatter.

impl ServerHandler for ProxyHandler

async fn initialize( &self, request: InitializeRequestParams, context: RequestContext<RoleServer>, ) -> Result<InitializeResult, ErrorData>

Connect per-session backends before returning capabilities.

fn get_info(&self) -> ServerInfo

async fn list_tools( &self, request: Option<PaginatedRequestParams>, context: RequestContext<RoleServer>, ) -> Result<ListToolsResult, ErrorData>

async fn call_tool( &self, request: CallToolRequestParams, context: RequestContext<RoleServer>, ) -> Result<CallToolResponse, ErrorData>

Handle a tools/call request from a client.

async fn list_resources( &self, request: Option<PaginatedRequestParams>, context: RequestContext<RoleServer>, ) -> Result<ListResourcesResult, ErrorData>

async fn read_resource( &self, request: ReadResourceRequestParams, context: RequestContext<RoleServer>, ) -> Result<ReadResourceResponse, ErrorData>

async fn list_resource_templates( &self, request: Option<PaginatedRequestParams>, context: RequestContext<RoleServer>, ) -> Result<ListResourceTemplatesResult, ErrorData>

async fn list_prompts( &self, request: Option<PaginatedRequestParams>, context: RequestContext<RoleServer>, ) -> Result<ListPromptsResult, ErrorData>

async fn get_prompt( &self, request: GetPromptRequestParams, context: RequestContext<RoleServer>, ) -> Result<GetPromptResponse, ErrorData>

async fn complete( &self, request: CompleteRequestParams, context: RequestContext<RoleServer>, ) -> Result<CompleteResult, ErrorData>

async fn subscribe( &self, request: SubscribeRequestParams, context: RequestContext<RoleServer>, ) -> Result<(), ErrorData>

async fn unsubscribe( &self, request: UnsubscribeRequestParams, context: RequestContext<RoleServer>, ) -> Result<(), ErrorData>

async fn set_level( &self, request: SetLevelRequestParams, context: RequestContext<RoleServer>, ) -> Result<(), ErrorData>

async fn enqueue_task( &self, request: CallToolRequestParams, context: RequestContext<RoleServer>, ) -> Result<CreateTaskResult, ErrorData>

async fn list_tasks( &self, request: Option<PaginatedRequestParams>, context: RequestContext<RoleServer>, ) -> Result<ListTasksResult, ErrorData>

async fn get_task_info( &self, request: GetTaskParams, context: RequestContext<RoleServer>, ) -> Result<GetTaskResult, ErrorData>

async fn get_task_result( &self, request: GetTaskPayloadParams, context: RequestContext<RoleServer>, ) -> Result<GetTaskPayloadResult, ErrorData>

async fn cancel_task( &self, request: CancelTaskParams, context: RequestContext<RoleServer>, ) -> Result<CancelTaskResult, ErrorData>

async fn on_initialized(&self, context: NotificationContext<RoleServer>)

async fn on_progress( &self, notification: ProgressNotificationParam, _context: NotificationContext<RoleServer>, )

async fn on_cancelled( &self, notification: CancelledNotificationParam, _context: NotificationContext<RoleServer>, )

fn ping( &self, context: RequestContext<RoleServer>, ) -> impl Future<Output = Result<(), ErrorData>> + MaybeSendFuture

fn supported_protocol_versions(&self) -> Cow<'static, [ProtocolVersion]>

Return the protocol versions supported by this server.

fn discover( &self, context: RequestContext<RoleServer>, ) -> impl Future<Output = Result<DiscoverResult, ErrorData>> + MaybeSendFuture

Return this server’s discovery information.

fn get_tool(&self, _name: &str) -> Option<Tool>

Get a tool definition by name.

fn on_custom_request( &self, request: CustomRequest, context: RequestContext<RoleServer>, ) -> impl Future<Output = Result<CustomResult, ErrorData>> + MaybeSendFuture

fn on_roots_list_changed( &self, context: NotificationContext<RoleServer>, ) -> impl Future<Output = ()> + MaybeSendFuture

fn on_task_status( &self, params: TaskStatusNotificationParam, context: NotificationContext<RoleServer>, ) -> impl Future<Output = ()> + MaybeSendFuture

fn on_custom_notification( &self, notification: CustomNotification, context: NotificationContext<RoleServer>, ) -> impl Future<Output = ()> + MaybeSendFuture