Module io.modelcontextprotocol.sdk.mcp

Package io.modelcontextprotocol.server.transport

Class HttpServletStreamableServerTransportProvider

java.lang.Object

jakarta.servlet.GenericServlet

jakarta.servlet.http.HttpServlet

io.modelcontextprotocol.server.transport.HttpServletStreamableServerTransportProvider

All Implemented Interfaces:

McpServerTransportProviderBase, McpStreamableServerTransportProvider, jakarta.servlet.Servlet, jakarta.servlet.ServletConfig, Serializable

@WebServlet(asyncSupported=true)
public class HttpServletStreamableServerTransportProvider
extends jakarta.servlet.http.HttpServlet
implements McpStreamableServerTransportProvider

Server-side implementation of the Model Context Protocol (MCP) streamable transport layer using HTTP with Server-Sent Events (SSE) through HttpServlet. This implementation provides a bridge between synchronous HttpServlet operations and reactive programming patterns to maintain compatibility with the reactive transport interface.

This is the HttpServlet equivalent of io.modelcontextprotocol.server.transport.WebMvcStreamableServerTransportProvider for the core MCP module, providing streamable HTTP transport functionality without Spring dependencies.

Author:

Zachary German, Christian Tzolov, Dariusz Jędrzejczyk

See Also:

• McpStreamableServerTransportProvider
• HttpServlet
• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	HttpServletStreamableServerTransportProvider.Builder	Builder for creating instances of HttpServletStreamableServerTransportProvider.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	APPLICATION_JSON
static final String	ENDPOINT_EVENT_TYPE	Event type for sending the message endpoint URI to clients.
static final String	FAILED_TO_SEND_ERROR_RESPONSE
static final String	MESSAGE_EVENT_TYPE	Event type for JSON-RPC messages sent through the SSE connection.
static final String	TEXT_EVENT_STREAM
static final String	UTF_8

Fields inherited from class jakarta.servlet.http.HttpServlet

LEGACY_DO_HEAD

Method Summary

Modifier and Type	Method	Description
static HttpServletStreamableServerTransportProvider.Builder	builder()
reactor.core.publisher.Mono<Void>	closeGracefully()	Initiates a graceful shutdown of the transport.
void	destroy()	Cleans up resources when the servlet is being destroyed.
protected void	doDelete(jakarta.servlet.http.HttpServletRequest request, jakarta.servlet.http.HttpServletResponse response)	Handles DELETE requests for session deletion.
protected void	doGet(jakarta.servlet.http.HttpServletRequest request, jakarta.servlet.http.HttpServletResponse response)	Handles GET requests to establish SSE connections and message replay.
protected void	doPost(jakarta.servlet.http.HttpServletRequest request, jakarta.servlet.http.HttpServletResponse response)	Handles POST requests for incoming JSON-RPC messages from clients.
reactor.core.publisher.Mono<Void>	notifyClients(String method, Object params)	Broadcasts a notification to all connected clients through their SSE connections.
List<String>	protocolVersions()	Returns the protocol version supported by this transport provider.
void	responseError(jakarta.servlet.http.HttpServletResponse response, int httpCode, McpError mcpError)
void	setSessionFactory(McpStreamableServerSession.Factory sessionFactory)	Sets the session factory that will be used to create sessions for new clients.

Methods inherited from class jakarta.servlet.http.HttpServlet

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

Methods inherited from interface io.modelcontextprotocol.spec.McpStreamableServerTransportProvider

close

Field Details

MESSAGE_EVENT_TYPE

public static final String MESSAGE_EVENT_TYPE

Event type for JSON-RPC messages sent through the SSE connection.

See Also:

• Constant Field Values

ENDPOINT_EVENT_TYPE

public static final String ENDPOINT_EVENT_TYPE

Event type for sending the message endpoint URI to clients.

See Also:

• Constant Field Values

UTF_8

public static final String UTF_8

See Also:

• Constant Field Values

APPLICATION_JSON

public static final String APPLICATION_JSON

See Also:

• Constant Field Values

TEXT_EVENT_STREAM

public static final String TEXT_EVENT_STREAM

See Also:

• Constant Field Values

FAILED_TO_SEND_ERROR_RESPONSE

public static final String FAILED_TO_SEND_ERROR_RESPONSE

See Also:

• Constant Field Values

Method Details

protocolVersions

public List<String> protocolVersions()

Description copied from interface: McpServerTransportProviderBase

Returns the protocol version supported by this transport provider.

Specified by:

protocolVersions in interface McpServerTransportProviderBase

Returns:

the protocol version as a string

setSessionFactory

public void setSessionFactory(McpStreamableServerSession.Factory sessionFactory)

Description copied from interface: McpStreamableServerTransportProvider

Sets the session factory that will be used to create sessions for new clients. An implementation of the MCP server MUST call this method before any MCP interactions take place.

Specified by:

setSessionFactory in interface McpStreamableServerTransportProvider

Parameters:

sessionFactory - the session factory to be used for initiating client sessions

notifyClients

public reactor.core.publisher.Mono<Void> notifyClients(String method,
 Object params)

Broadcasts a notification to all connected clients through their SSE connections. If any errors occur during sending to a particular client, they are logged but don't prevent sending to other clients.

Specified by:

notifyClients in interface McpServerTransportProviderBase

Specified by:

notifyClients in interface McpStreamableServerTransportProvider

Parameters:

method - The method name for the notification

params - The parameters for the notification

Returns:

A Mono that completes when the broadcast attempt is finished

See Also:

• McpSession.sendNotification(String, Map)

closeGracefully

public reactor.core.publisher.Mono<Void> closeGracefully()

Initiates a graceful shutdown of the transport.

Specified by:

closeGracefully in interface McpServerTransportProviderBase

Specified by:

closeGracefully in interface McpStreamableServerTransportProvider

Returns:

A Mono that completes when all cleanup operations are finished

doGet

protected void doGet(jakarta.servlet.http.HttpServletRequest request,
 jakarta.servlet.http.HttpServletResponse response)
              throws jakarta.servlet.ServletException,
IOException

Handles GET requests to establish SSE connections and message replay.

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

Handles POST requests for incoming JSON-RPC messages from clients.

Overrides:

doPost in class jakarta.servlet.http.HttpServlet

Parameters:

request - The HTTP servlet request containing the JSON-RPC message

response - The HTTP servlet response

Throws:

jakarta.servlet.ServletException - If a servlet-specific error occurs

IOException - If an I/O error occurs

doDelete

protected void doDelete(jakarta.servlet.http.HttpServletRequest request,
 jakarta.servlet.http.HttpServletResponse response)
                 throws jakarta.servlet.ServletException,
IOException

Handles DELETE requests for session deletion.

Overrides:

doDelete 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

responseError

public void responseError(jakarta.servlet.http.HttpServletResponse response,
 int httpCode,
 McpError mcpError)
                   throws IOException

Throws:

IOException

destroy

public void destroy()

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

builder

public static HttpServletStreamableServerTransportProvider.Builder builder()