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feat(mcp): Add configurable SSE endpoint support for MCP client transports #2960

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Merged
merged 1 commit into from
May 1, 2025
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feat(mcp): Add configurable SSE endpoint support for MCP client transports #2960

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10 changes: 8 additions & 2 deletions .../springframework/ai/mcp/client/autoconfigure/SseHttpClientTransportAutoConfiguration.java
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Original file line number Diff line number Diff line change
Expand Up @@ -94,8 +94,14 @@ public List<NamedClientMcpTransport> mcpHttpClientTransports(McpSseClientPropert

for (Map.Entry<String, SseParameters> serverParameters : sseProperties.getConnections().entrySet()) {

var transport = new HttpClientSseClientTransport(HttpClient.newBuilder(), serverParameters.getValue().url(),
objectMapper);
String baseUrl = serverParameters.getValue().url();
String sseEndpoint = serverParameters.getValue().sseEndpoint() != null
? serverParameters.getValue().sseEndpoint() : "/sse";
var transport = HttpClientSseClientTransport.builder(baseUrl)
.sseEndpoint(sseEndpoint)
.clientBuilder(HttpClient.newBuilder())
.objectMapper(objectMapper)
.build();
sseTransports.add(new NamedClientMcpTransport(serverParameters.getKey(), transport));
}

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7 changes: 6 additions & 1 deletion ...org/springframework/ai/mcp/client/autoconfigure/SseWebFluxTransportAutoConfiguration.java
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Expand Up @@ -90,7 +90,12 @@ public List<NamedClientMcpTransport> webFluxClientTransports(McpSseClientPropert

for (Map.Entry<String, SseParameters> serverParameters : sseProperties.getConnections().entrySet()) {
var webClientBuilder = webClientBuilderTemplate.clone().baseUrl(serverParameters.getValue().url());
var transport = new WebFluxSseClientTransport(webClientBuilder, objectMapper);
String sseEndpoint = serverParameters.getValue().sseEndpoint() != null
? serverParameters.getValue().sseEndpoint() : "/sse";
var transport = WebFluxSseClientTransport.builder(webClientBuilder)
.sseEndpoint(sseEndpoint)
.objectMapper(objectMapper)
.build();
sseTransports.add(new NamedClientMcpTransport(serverParameters.getKey(), transport));
}

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3 changes: 2 additions & 1 deletion ...va/org/springframework/ai/mcp/client/autoconfigure/properties/McpSseClientProperties.java
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Expand Up @@ -67,8 +67,9 @@ public Map<String, SseParameters> getConnections() {
* Parameters for configuring an SSE connection to an MCP server.
*
* @param url the URL endpoint for SSE communication with the MCP server
* @param sseEndpoint the SSE endpoint for the MCP server
*/
public record SseParameters(String url) {
public record SseParameters(String url, String sseEndpoint) {
}

}
152 changes: 149 additions & 3 deletions ...ngframework/ai/mcp/client/autoconfigure/SseHttpClientTransportAutoConfigurationTests.java
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Expand Up @@ -16,28 +16,39 @@

package org.springframework.ai.mcp.client.autoconfigure;

import java.lang.reflect.Field;
import java.util.List;

import com.fasterxml.jackson.databind.ObjectMapper;
import io.modelcontextprotocol.client.transport.HttpClientSseClientTransport;
import org.junit.jupiter.api.Test;

import org.springframework.boot.autoconfigure.AutoConfigurations;
import org.springframework.boot.test.context.FilteredClassLoader;
import org.springframework.boot.test.context.runner.ApplicationContextRunner;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.util.ReflectionUtils;

import static org.assertj.core.api.Assertions.assertThat;

/**
* Tests for {@link SseHttpClientTransportAutoConfiguration}.
*
* @author Christian Tzolov
*/
public class SseHttpClientTransportAutoConfigurationTests {

private final ApplicationContextRunner applicationContext = new ApplicationContextRunner()
.withConfiguration(AutoConfigurations.of(SseHttpClientTransportAutoConfiguration.class));

@Test
void mcpHttpClientTransportsNotPresentIfMissingWebFluxSseClientTransportPresent() {

this.applicationContext.run(context -> assertThat(context.containsBean("mcpHttpClientTransports")).isFalse());
}

@Test
void mcpHttpClientTransportsPresentIfMissingWebFluxSseClientTransportNotPresent() {

this.applicationContext
.withClassLoader(
new FilteredClassLoader("io.modelcontextprotocol.client.transport.WebFluxSseClientTransport"))
Expand All @@ -46,12 +57,147 @@ void mcpHttpClientTransportsPresentIfMissingWebFluxSseClientTransportNotPresent(

@Test
void mcpHttpClientTransportsNotPresentIfMcpClientDisabled() {

this.applicationContext
.withClassLoader(
new FilteredClassLoader("io.modelcontextprotocol.client.transport.WebFluxSseClientTransport"))
.withPropertyValues("spring.ai.mcp.client.enabled", "false")
.run(context -> assertThat(context.containsBean("mcpHttpClientTransports")).isFalse());
}

@Test
void noTransportsCreatedWithEmptyConnections() {
this.applicationContext
.withClassLoader(
new FilteredClassLoader("io.modelcontextprotocol.client.transport.WebFluxSseClientTransport"))
.run(context -> {
List<NamedClientMcpTransport> transports = context.getBean("mcpHttpClientTransports", List.class);
assertThat(transports).isEmpty();
});
}

@Test
void singleConnectionCreatesOneTransport() {
this.applicationContext
.withClassLoader(
new FilteredClassLoader("io.modelcontextprotocol.client.transport.WebFluxSseClientTransport"))
.withPropertyValues("spring.ai.mcp.client.sse.connections.server1.url=http://localhost:8080")
.run(context -> {
List<NamedClientMcpTransport> transports = context.getBean("mcpHttpClientTransports", List.class);
assertThat(transports).hasSize(1);
assertThat(transports.get(0).name()).isEqualTo("server1");
assertThat(transports.get(0).transport()).isInstanceOf(HttpClientSseClientTransport.class);
});
}

@Test
void multipleConnectionsCreateMultipleTransports() {
this.applicationContext
.withClassLoader(
new FilteredClassLoader("io.modelcontextprotocol.client.transport.WebFluxSseClientTransport"))
.withPropertyValues("spring.ai.mcp.client.sse.connections.server1.url=http://localhost:8080",
"spring.ai.mcp.client.sse.connections.server2.url=http://otherserver:8081")
.run(context -> {
List<NamedClientMcpTransport> transports = context.getBean("mcpHttpClientTransports", List.class);
assertThat(transports).hasSize(2);
assertThat(transports).extracting("name").containsExactlyInAnyOrder("server1", "server2");
assertThat(transports).extracting("transport")
.allMatch(transport -> transport instanceof HttpClientSseClientTransport);
for (NamedClientMcpTransport transport : transports) {
assertThat(transport.transport()).isInstanceOf(HttpClientSseClientTransport.class);
assertThat(getSseEndpoint((HttpClientSseClientTransport) transport.transport())).isEqualTo("/sse");
}
});
}

@Test
void customSseEndpointIsRespected() {
this.applicationContext
.withClassLoader(
new FilteredClassLoader("io.modelcontextprotocol.client.transport.WebFluxSseClientTransport"))
.withPropertyValues("spring.ai.mcp.client.sse.connections.server1.url=http://localhost:8080",
"spring.ai.mcp.client.sse.connections.server1.sse-endpoint=/custom-sse")
.run(context -> {
List<NamedClientMcpTransport> transports = context.getBean("mcpHttpClientTransports", List.class);
assertThat(transports).hasSize(1);
assertThat(transports.get(0).name()).isEqualTo("server1");
assertThat(transports.get(0).transport()).isInstanceOf(HttpClientSseClientTransport.class);

assertThat(getSseEndpoint((HttpClientSseClientTransport) transports.get(0).transport()))
.isEqualTo("/custom-sse");
});
}

@Test
void customObjectMapperIsUsed() {
this.applicationContext
.withClassLoader(
new FilteredClassLoader("io.modelcontextprotocol.client.transport.WebFluxSseClientTransport"))
.withUserConfiguration(CustomObjectMapperConfiguration.class)
.withPropertyValues("spring.ai.mcp.client.sse.connections.server1.url=http://localhost:8080")
.run(context -> {
assertThat(context.getBean(ObjectMapper.class)).isNotNull();
List<NamedClientMcpTransport> transports = context.getBean("mcpHttpClientTransports", List.class);
assertThat(transports).hasSize(1);
});
}

@Test
void defaultSseEndpointIsUsedWhenNotSpecified() {
this.applicationContext
.withClassLoader(
new FilteredClassLoader("io.modelcontextprotocol.client.transport.WebFluxSseClientTransport"))
.withPropertyValues("spring.ai.mcp.client.sse.connections.server1.url=http://localhost:8080")
.run(context -> {
List<NamedClientMcpTransport> transports = context.getBean("mcpHttpClientTransports", List.class);
assertThat(transports).hasSize(1);
assertThat(transports.get(0).name()).isEqualTo("server1");
assertThat(transports.get(0).transport()).isInstanceOf(HttpClientSseClientTransport.class);
// Default SSE endpoint is "/sse" as specified in the configuration class
});
}

@Test
void mixedConnectionsWithAndWithoutCustomSseEndpoint() {
this.applicationContext
.withClassLoader(
new FilteredClassLoader("io.modelcontextprotocol.client.transport.WebFluxSseClientTransport"))
.withPropertyValues("spring.ai.mcp.client.sse.connections.server1.url=http://localhost:8080",
"spring.ai.mcp.client.sse.connections.server1.sse-endpoint=/custom-sse",
"spring.ai.mcp.client.sse.connections.server2.url=http://otherserver:8081")
.run(context -> {
List<NamedClientMcpTransport> transports = context.getBean("mcpHttpClientTransports", List.class);
assertThat(transports).hasSize(2);
assertThat(transports).extracting("name").containsExactlyInAnyOrder("server1", "server2");
assertThat(transports).extracting("transport")
.allMatch(transport -> transport instanceof HttpClientSseClientTransport);
for (NamedClientMcpTransport transport : transports) {
assertThat(transport.transport()).isInstanceOf(HttpClientSseClientTransport.class);
if (transport.name().equals("server1")) {
assertThat(getSseEndpoint((HttpClientSseClientTransport) transport.transport()))
.isEqualTo("/custom-sse");
}
else {
assertThat(getSseEndpoint((HttpClientSseClientTransport) transport.transport()))
.isEqualTo("/sse");
}
}
});
}

private String getSseEndpoint(HttpClientSseClientTransport transport) {
Field privateField = ReflectionUtils.findField(HttpClientSseClientTransport.class, "sseEndpoint");
ReflectionUtils.makeAccessible(privateField);
return (String) ReflectionUtils.getField(privateField, transport);
}

@Configuration
static class CustomObjectMapperConfiguration {

@Bean
ObjectMapper objectMapper() {
return new ObjectMapper();
}

}

}
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