feat: supported McpServerSessionListener on SseSession events.

[big-mouth-cn]

Motivation and Context

#59
#77

feat:

In the development of MCP in business systems, the SSE server usually needs to obtain client identity information, such as user information, when processing with the @tool tool. Currently, most MCP clients support passing user information through HTTP Headers, such as API KEY. However, the MCP SDK cannot pass HTTP Headers to the @tool method. Therefore, this change mainly supports this requirement.

fix:

In addition, it also fixes the issue where the keys and corresponding values of the sessions variable in WebMvcSseServerTransportProvider are inconsistent with the sessionId.

How Has This Been Tested?

with Spring-AI

McpWebFluxServerAutoConfiguration.java

@Bean
@ConditionalOnMissingBean
public WebFluxSseServerTransportProvider webFluxTransport(ObjectProvider<ObjectMapper> objectMapperProvider,
		McpServerProperties serverProperties,
		ObjectProvider<McpServerSessionListener<ServerRequest>> mcpServerSessionListeners) {
	ObjectMapper objectMapper = objectMapperProvider.getIfAvailable(ObjectMapper::new);
	WebFluxSseServerTransportProvider webFluxSseServerTransportProvider = new WebFluxSseServerTransportProvider(
			objectMapper, serverProperties.getSseMessageEndpoint(), serverProperties.getSseEndpoint());
	webFluxSseServerTransportProvider.setMcpServerSessionListener(mcpServerSessionListeners.getIfAvailable());
	return webFluxSseServerTransportProvider;
}

ToolProviderAutoConfiguration.java

@Configuration
public class ToolProviderAutoConfiguration {

    public static final Map<String, HttpHeaders> sessionHeaders = new ConcurrentHashMap<>();

    @Bean
    public ToolCallbackProvider toolCallbackProvider(WeatherToolProvider weatherToolProvider) {
        return MethodToolCallbackProvider.builder().toolObjects(weatherToolProvider).build();
    }

    @Bean
    public McpServerSessionListener<ServerRequest> mcpServerSessionListener() {
        return new McpServerSessionListener<>() {

            @Override
            public void onConnection(McpServerSession session, ServerRequest request) {
                HttpHeaders httpHeaders = request.headers().asHttpHeaders();
                sessionHeaders.put(session.getId(), httpHeaders);
            }

            @Override
            public void onMessage(McpServerSession session, ServerRequest request) {
            }
        };
    }
}

WeatherToolProvider.java

@Service
public class WeatherToolProvider {

    @Tool(name = "query_weather", description = "查询天气信息。")
    public String queryWeather(String city,
                               ToolContext toolContext) {
        Object o = toolContext.getContext().get("exchange");
        if (o instanceof McpSyncServerExchange) {
            String sessionId = ((McpSyncServerExchange) o).getSessionId();
            log.info("sessionId: {}", sessionId);

            HttpHeaders httpHeaders = ToolProviderAutoConfiguration.sessionHeaders.get(sessionId);
            log.info("httpHeaders: {}", httpHeaders);
        }

        return "今天晴转多云，18-26°C，东南风3-4级。";
    }
}

Breaking Changes

No need, add an interface, implementation is not necessary.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

After the change is merged, I will submit the auto configure code for spring-ai.

[big-mouth-cn]

Hi maintainers, this PR is ready to be merged but needs a workflow and code approval from someone with write access. Could someone please help review and approve it? Thanks! 🙏