From cf5468ab4b8e331d3ab78298f37faa75bca497ec Mon Sep 17 00:00:00 2001 From: codezkk <52305579+codezkk@users.noreply.github.com> Date: Fri, 1 Aug 2025 16:01:24 +0800 Subject: [PATCH 1/3] Update ResponseSubscribers.java sink.must() must be executed, otherwise in the case of empty return (such as notify), the deliveredSink of sendMessage will not be able to process the stream correctly, resulting in Client failed to initialize by explicit API call --- .../client/transport/ResponseSubscribers.java | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/mcp/src/main/java/io/modelcontextprotocol/client/transport/ResponseSubscribers.java b/mcp/src/main/java/io/modelcontextprotocol/client/transport/ResponseSubscribers.java index eb9d3c65c..48525741f 100644 --- a/mcp/src/main/java/io/modelcontextprotocol/client/transport/ResponseSubscribers.java +++ b/mcp/src/main/java/io/modelcontextprotocol/client/transport/ResponseSubscribers.java @@ -237,10 +237,10 @@ protected void hookOnNext(String line) { @Override protected void hookOnComplete() { - if (this.eventBuilder.length() > 0) { - String data = this.eventBuilder.toString(); - this.sink.next(new AggregateResponseEvent(responseInfo, data)); - } + // sink.next() is must + String data = this.eventBuilder.toString(); + this.sink.next(new AggregateResponseEvent(responseInfo, data)); + this.sink.complete(); } From 7ddec7c2ba04fa8f28598c0bd193fc348d5d7a6f Mon Sep 17 00:00:00 2001 From: codezkk <52305579+codezkk@users.noreply.github.com> Date: Tue, 5 Aug 2025 09:54:40 +0800 Subject: [PATCH 2/3] add test Tests for the "Client failed to initialize by explicit API call" problem. --- ...ientStreamableHttpTransportFor200Test.java | 91 +++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 mcp/src/test/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransportFor200Test.java diff --git a/mcp/src/test/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransportFor200Test.java b/mcp/src/test/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransportFor200Test.java new file mode 100644 index 000000000..08f5530a7 --- /dev/null +++ b/mcp/src/test/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransportFor200Test.java @@ -0,0 +1,91 @@ +/* + * Copyright 2024-2025 the original author or authors. + */ + +package io.modelcontextprotocol.client.transport; + +import com.sun.net.httpserver.HttpServer; +import io.modelcontextprotocol.spec.McpSchema; +import org.junit.jupiter.api.AfterAll; +import org.junit.jupiter.api.BeforeAll; +import org.junit.jupiter.api.Test; +import org.junit.jupiter.api.Timeout; +import reactor.test.StepVerifier; + +import java.io.IOException; +import java.net.InetSocketAddress; +import java.net.URI; +import java.net.URISyntaxException; +import java.util.concurrent.TimeUnit; +import java.util.function.Consumer; + +import static org.mockito.Mockito.mock; +import static org.mockito.ArgumentMatchers.any; +import static org.mockito.ArgumentMatchers.eq; +import static org.mockito.Mockito.atLeastOnce; +import static org.mockito.Mockito.verify; + +/** + * Tests for the "Client failed to initialize by explicit API call" problem. + * + * @author codezkk + */ +public class HttpClientStreamableHttpTransportFor200Test { + + static String host = "http://localhost:3001"; + + static HttpServer server; + + @BeforeAll + static void startContainer() throws IOException { + server = HttpServer.create(new InetSocketAddress(3001), 0); + server.createContext("/mcp", exchange -> { + exchange.getResponseHeaders().set("Content-Type", "application/json"); + exchange.sendResponseHeaders(200, 0); + exchange.close(); + }); + server.setExecutor(null); + server.start(); + } + + @AfterAll + static void stopContainer() { + server.stop(1); + } + + /** + * Regardless of the response (even if the response is null and the content-type is + * present), notify should handle it correctly. + * @throws URISyntaxException + */ + @Test + @Timeout(value = 3, unit = TimeUnit.SECONDS) + void testNotificationInitialized() throws URISyntaxException { + + var uri = new URI(host + "/mcp"); + var mockRequestCustomizer = mock(SyncHttpRequestCustomizer.class); + var transport = HttpClientStreamableHttpTransport.builder(host) + .httpRequestCustomizer(mockRequestCustomizer) + .build(); + + withTransport(transport, (t) -> { + var testNotification = new McpSchema.JSONRPCNotification(McpSchema.JSONRPC_VERSION, + McpSchema.METHOD_NOTIFICATION_INITIALIZED, null); + + StepVerifier.create(t.sendMessage(testNotification)).verifyComplete(); + + verify(mockRequestCustomizer, atLeastOnce()).customize(any(), eq("GET"), eq(uri), + eq("{\"jsonrpc\":\"2.0\",\"method\":\"notifications/initialized\"}")); + }); + } + + void withTransport(HttpClientStreamableHttpTransport transport, Consumer c) { + try { + c.accept(transport); + } + finally { + StepVerifier.create(transport.closeGracefully()).verifyComplete(); + } + } + +} From 483462f430c4f2de88931e04ffdfe93de41ec13e Mon Sep 17 00:00:00 2001 From: codezkk Date: Wed, 6 Aug 2025 06:46:06 +0800 Subject: [PATCH 3/3] code style --- .../client/transport/ResponseSubscribers.java | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mcp/src/main/java/io/modelcontextprotocol/client/transport/ResponseSubscribers.java b/mcp/src/main/java/io/modelcontextprotocol/client/transport/ResponseSubscribers.java index 48525741f..98f52a646 100644 --- a/mcp/src/main/java/io/modelcontextprotocol/client/transport/ResponseSubscribers.java +++ b/mcp/src/main/java/io/modelcontextprotocol/client/transport/ResponseSubscribers.java @@ -237,10 +237,10 @@ protected void hookOnNext(String line) { @Override protected void hookOnComplete() { - // sink.next() is must + // sink.next() is must String data = this.eventBuilder.toString(); this.sink.next(new AggregateResponseEvent(responseInfo, data)); - + this.sink.complete(); }