Module io.modelcontextprotocol.sdk.mcp
Package io.modelcontextprotocol.server.transport

Class HttpServletSseServerTransport

java.lang.Object
jakarta.servlet.GenericServlet
jakarta.servlet.http.HttpServlet
io.modelcontextprotocol.server.transport.HttpServletSseServerTransport
All Implemented Interfaces:
McpTransport, ServerMcpTransport, jakarta.servlet.Servlet, jakarta.servlet.ServletConfig, Serializable
@WebServlet(asyncSupported=true) @Deprecated public class HttpServletSseServerTransport extends jakarta.servlet.http.HttpServlet implements ServerMcpTransport
Deprecated.
This class will be removed in 0.9.0. Use HttpServletSseServerTransportProvider.

The transport handles two types of endpoints:

  • SSE endpoint (/sse) - Establishes a long-lived connection for server-to-client events
  • Message endpoint (configurable) - Handles client-to-server message requests

Features:

  • Asynchronous message handling using Servlet 6.0 async support
  • Session management for multiple client connections
  • Graceful shutdown support
  • Error handling and response formatting
A Servlet-based implementation of the MCP HTTP with Server-Sent Events (SSE) transport specification. This implementation provides similar functionality to WebFluxSseServerTransport but uses the traditional Servlet API instead of WebFlux.
Author:
Christian Tzolov, Alexandros Pappas
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    APPLICATION_JSON
    Deprecated.
     
    static final String
    DEFAULT_SSE_ENDPOINT
    Deprecated.
    Default endpoint path for SSE connections
    static final String
    ENDPOINT_EVENT_TYPE
    Deprecated.
    Event type for endpoint information
    static final String
    FAILED_TO_SEND_ERROR_RESPONSE
    Deprecated.
     
    static final String
    MESSAGE_EVENT_TYPE
    Deprecated.
    Event type for regular messages
    static final String
    UTF_8
    Deprecated.
     

    Fields inherited from class jakarta.servlet.http.HttpServlet

    LEGACY_DO_HEAD

  • Constructor Summary

    Constructors
    Constructor
    Description
    HttpServletSseServerTransport(com.fasterxml.jackson.databind.ObjectMapper objectMapper, String messageEndpoint)
    Deprecated.
    Creates a new HttpServletSseServerTransport instance with the default SSE endpoint.
    HttpServletSseServerTransport(com.fasterxml.jackson.databind.ObjectMapper objectMapper, String messageEndpoint, String sseEndpoint)
    Deprecated.
    Creates a new HttpServletSseServerTransport instance with a custom SSE endpoint.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    close()
    Deprecated.
    Closes the transport.
    reactor.core.publisher.Mono<Void>
    closeGracefully()
    Deprecated.
    Initiates a graceful shutdown of the transport.
    reactor.core.publisher.Mono<Void>
    connect(Function<reactor.core.publisher.Mono<McpSchema.JSONRPCMessage>,reactor.core.publisher.Mono<McpSchema.JSONRPCMessage>> handler)
    Deprecated.
    Sets up the message handler for processing client requests.
    void
    destroy()
    Deprecated.
    Cleans up resources when the servlet is being destroyed.
    protected void
    doGet(jakarta.servlet.http.HttpServletRequest request, jakarta.servlet.http.HttpServletResponse response)
    Deprecated.
    Handles GET requests to establish SSE connections.
    protected void
    doPost(jakarta.servlet.http.HttpServletRequest request, jakarta.servlet.http.HttpServletResponse response)
    Deprecated.
    Handles POST requests for client messages.
    reactor.core.publisher.Mono<Void>
    sendMessage(McpSchema.JSONRPCMessage message)
    Deprecated.
    Broadcasts a message to all connected clients.
    <T> T
    unmarshalFrom(Object data, com.fasterxml.jackson.core.type.TypeReference<T> typeRef)
    Deprecated.
    Unmarshals data from one type to another using the object mapper.

    Methods inherited from class jakarta.servlet.http.HttpServlet

    doDelete, doHead, doOptions, doPatch, doPut, doTrace, getLastModified, init, isSensitiveHeader, service, service

    Methods inherited from class jakarta.servlet.GenericServlet

    getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

  • Constructor Details

    • HttpServletSseServerTransport

      public HttpServletSseServerTransport(com.fasterxml.jackson.databind.ObjectMapper objectMapper, String messageEndpoint, String sseEndpoint)
      Deprecated.
      Creates a new HttpServletSseServerTransport instance with a custom SSE endpoint.
      Parameters:
      objectMapper - The JSON object mapper to use for message serialization/deserialization
      messageEndpoint - The endpoint path where clients will send their messages
      sseEndpoint - The endpoint path where clients will establish SSE connections

    • HttpServletSseServerTransport

      public HttpServletSseServerTransport(com.fasterxml.jackson.databind.ObjectMapper objectMapper, String messageEndpoint)
      Deprecated.
      Creates a new HttpServletSseServerTransport instance with the default SSE endpoint.
      Parameters:
      objectMapper - The JSON object mapper to use for message serialization/deserialization
      messageEndpoint - The endpoint path where clients will send their messages

  • Method Details

    • doGet

      protected void doGet(jakarta.servlet.http.HttpServletRequest request, jakarta.servlet.http.HttpServletResponse response) throws jakarta.servlet.ServletException, IOException
      Deprecated.
      Handles GET requests to establish SSE connections.

      This method sets up a new SSE connection when a client connects to the SSE endpoint. It configures the response headers for SSE, creates a new session, and sends the initial endpoint information to the client.

      Overrides:
      doGet in class jakarta.servlet.http.HttpServlet
      Parameters:
      request - The HTTP servlet request
      response - The HTTP servlet response
      Throws:
      jakarta.servlet.ServletException - If a servlet-specific error occurs
      IOException - If an I/O error occurs

    • doPost

      protected void doPost(jakarta.servlet.http.HttpServletRequest request, jakarta.servlet.http.HttpServletResponse response) throws jakarta.servlet.ServletException, IOException
      Deprecated.
      Handles POST requests for client messages.

      This method processes incoming messages from clients, routes them through the connect handler if configured, and sends back the appropriate response. It handles error cases and formats error responses according to the MCP specification.

      Overrides:
      doPost in class jakarta.servlet.http.HttpServlet
      Parameters:
      request - The HTTP servlet request
      response - The HTTP servlet response
      Throws:
      jakarta.servlet.ServletException - If a servlet-specific error occurs
      IOException - If an I/O error occurs

    • connect

      public reactor.core.publisher.Mono<Void> connect(Function<reactor.core.publisher.Mono<McpSchema.JSONRPCMessage>,reactor.core.publisher.Mono<McpSchema.JSONRPCMessage>> handler)
      Deprecated.
      Sets up the message handler for processing client requests.
      Specified by:
      connect in interface McpTransport
      Parameters:
      handler - The function to process incoming messages and produce responses
      Returns:
      A Mono that completes when the handler is set up

    • sendMessage

      public reactor.core.publisher.Mono<Void> sendMessage(McpSchema.JSONRPCMessage message)
      Deprecated.
      Broadcasts a message to all connected clients.

      This method serializes the message and sends it to all active client sessions. If a client is disconnected, its session is removed.

      Specified by:
      sendMessage in interface McpTransport
      Parameters:
      message - The message to broadcast
      Returns:
      A Mono that completes when the message has been sent to all clients

    • close

      public void close()
      Deprecated.
      Closes the transport.

      This implementation delegates to the super class's close method.

      Specified by:
      close in interface McpTransport

    • unmarshalFrom

      public <T> T unmarshalFrom(Object data, com.fasterxml.jackson.core.type.TypeReference<T> typeRef)
      Deprecated.
      Unmarshals data from one type to another using the object mapper.
      Specified by:
      unmarshalFrom in interface McpTransport
      Type Parameters:
      T - The target type
      Parameters:
      data - The source data
      typeRef - The type reference for the target type
      Returns:
      The unmarshaled data

    • closeGracefully

      public reactor.core.publisher.Mono<Void> closeGracefully()
      Deprecated.
      Initiates a graceful shutdown of the transport.

      This method marks the transport as closing and closes all active client sessions. New connection attempts will be rejected during shutdown.

      Specified by:
      closeGracefully in interface McpTransport
      Returns:
      A Mono that completes when all sessions have been closed

    • destroy

      public void destroy()
      Deprecated.
      Cleans up resources when the servlet is being destroyed.

      This method ensures a graceful shutdown by closing all client connections before calling the parent's destroy method.

      Specified by:
      destroy in interface jakarta.servlet.Servlet
      Overrides:
      destroy in class jakarta.servlet.GenericServlet