Crate mcp_streamable_proxy 

MCP Streamable HTTP Proxy Module

This module provides a proxy implementation for MCP (Model Context Protocol) using Streamable HTTP transport with stateful session management.

Features

• Streamable HTTP Support: Uses rmcp with Streamable HTTP transport
• Stateful Sessions: Custom SessionManager with backend version tracking
• Per-session URL backends: each upstream session connects its own backend on initialize
• Shared stdio backends: one child process shared across sessions
• Hot Swap: Supports backend connection replacement (shared isolation)

Architecture

Client → Streamable HTTP → ProxyAwareSessionManager → ProxyHandler → Backend MCP Service
  URL (per-session): each session opens its own backend (connect on initialize)
  Stdio (shared): one backend, clones share Arcs + notification fan-out registry

Example

use mcp_streamable_proxy::{StreamClientConnection, McpClientConfig};

// Connect to an MCP server
let config = McpClientConfig::new("http://localhost:8080/mcp");
let conn = StreamClientConnection::connect(config).await?;

// List available tools
let tools = conn.list_tools().await?;

Re-exports

pub use backend_client::BackendNotificationBridge;

pub use backend_client::NotifyTarget;

pub use backend_client::ProgressRouteGuard;

pub use backend_client::UpstreamPeerRegistry;

pub use backend_client::UpstreamPeerSlot;

pub use backend_connector::BackendConnector;

pub use backend_connector::BackendIsolation;

pub use backend_connector::StdioBackendConnector;

pub use backend_connector::UrlBackendConnector;

pub use proxy_handler::BackendRunningService;

pub use proxy_handler::ProxyHandler;

pub use server::run_stream_server;

pub use server::run_stream_server_from_config;

pub use session_manager::ProxyAwareSessionManager;

pub use detector::is_streamable_http;

pub use detector::is_streamable_http_with_headers;

pub use server_builder::BackendConfig;

pub use server_builder::StreamServerBuilder;

pub use server_builder::StreamServerConfig;

pub use client::StreamClientConnection;

pub use client::ToolInfo;

pub use fallback::DiscoverySnapshot;

pub use fallback::FallbackMetadata;

Modules

backend_client

Backend client handler that bridges server notifications to upstream peers.

backend_connector

Backend connection factories for shared (stdio) and per-session (URL) isolation.

client

Streamable HTTP Client Connection Module

config

Configuration types for Streamable HTTP proxy

detector

fallback

proxy_handler

server

Streamable HTTP server implementation

server_builder

Streamable HTTP Server Builder

session_manager

Session Manager with backend version tracking

Structs

ClientCapabilities

Builder

Implementation

LocalSessionManager

McpClientConfig

Configuration for MCP client connections

McpServiceConfig

MCP 服务配置

Peer

An interface to fetch the remote client or server

RoleClient

RoleServer

RunningService

StreamableHttpClientTransportConfig

StreamableHttpServerConfig

StreamableHttpService

Streamable HTTP server

TokioChildProcess

ToolFilter

工具过滤配置

Traits

ServerHandler

ServiceExt

Functions

stdio

StdIO Transport

Type Aliases

ClientConfig

A client’s own configuration: the protocol version, capabilities, and implementation identity it advertises to servers.

ServerConfig

A server’s own configuration: the protocol version, capabilities, implementation identity, and instructions it advertises to clients.

StreamableHttpClientTransport

A client-agnostic HTTP transport for RMCP that supports streaming responses.