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[fel] Refactor DefaultMcpClient: centralize request logic and improve robustness #143

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Merged
CodeCasterX merged 1 commit into from
May 27, 2025
Merged

[fel] Refactor DefaultMcpClient: centralize request logic and improve robustness #143

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171 changes: 58 additions & 113 deletions ...ol-mcp-client/src/main/java/modelengine/fel/tool/mcp/client/support/DefaultMcpClient.java
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@

import modelengine.fel.tool.mcp.client.McpClient;
import modelengine.fel.tool.mcp.entity.ClientSchema;
import modelengine.fel.tool.mcp.entity.Event;
import modelengine.fel.tool.mcp.entity.JsonRpc;
import modelengine.fel.tool.mcp.entity.Method;
import modelengine.fel.tool.mcp.entity.ServerSchema;
Expand Down Expand Up @@ -43,6 +44,7 @@
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.BiConsumer;
import java.util.function.Consumer;

/**
Expand Down Expand Up @@ -129,8 +131,8 @@ public void initialize() {
.runnable(this::pingServer)
.policy(ExecutePolicy.fixedDelay(DELAY_MILLIS))
.build(), DELAY_MILLIS);
while (!this.waitInitialized()) {
ThreadUtils.sleep(100);
if (!this.waitInitialized()) {
throw new IllegalStateException("Failed to initialize.");
}
}

Expand All @@ -142,7 +144,7 @@ private void consumeTextEvent(TextEvent textEvent) {
if (StringUtils.isBlank(textEvent.event()) || StringUtils.isBlank((String) textEvent.data())) {
return;
}
if (Objects.equals(textEvent.event(), "endpoint")) {
if (Objects.equals(textEvent.event(), Event.ENDPOINT.code())) {
this.initializeMcpServer(textEvent);
return;
}
Expand Down Expand Up @@ -173,64 +175,20 @@ private void pingServer() {
log.info("MCP client is not initialized and {} method will be delayed.", Method.PING.code());
return;
}
HttpClassicClientRequest request =
this.client.createRequest(HttpRequestMethod.POST, this.baseUri + this.messageEndpoint);
long currentId = this.getNextId();
JsonRpc.Request<Long> rpcRequest = JsonRpc.createRequest(currentId, Method.PING.code());
request.entity(Entity.createObject(request, rpcRequest));
log.info("Send {} method to MCP server. [sessionId={}, request={}]",
Method.PING.code(),
this.sessionId,
rpcRequest);
try (HttpClassicClientResponse<Object> exchange = request.exchange(Object.class)) {
if (exchange.statusCode() >= 200 && exchange.statusCode() < 300) {
log.info("Send {} method to MCP server successfully. [sessionId={}, statusCode={}]",
Method.PING.code(),
this.sessionId,
exchange.statusCode());
} else {
log.error("Failed to {} MCP server. [sessionId={}, statusCode={}]",
Method.PING.code(),
this.sessionId,
exchange.statusCode());
}
} catch (IOException e) {
throw new IllegalStateException(e);
}
this.post2McpServer(Method.PING, null, null);
}

private void initializeMcpServer(TextEvent textEvent) {
this.messageEndpoint = textEvent.data().toString();
HttpClassicClientRequest request =
this.client.createRequest(HttpRequestMethod.POST, this.baseUri + this.messageEndpoint);
this.sessionId =
request.queries().first("session_id").orElseThrow(() -> new IllegalStateException("no session_id"));
long currentId = this.getNextId();
this.responseConsumers.put(currentId, this::initializedMcpServer);
ClientSchema schema = new ClientSchema("2024-11-05",
new ClientSchema.Capabilities(),
new ClientSchema.Info("FIT MCP Client", "3.5.0-SNAPSHOT"));
JsonRpc.Request<Long> rpcRequest = JsonRpc.createRequest(currentId, Method.INITIALIZE.code(), schema);
request.entity(Entity.createObject(request, rpcRequest));
log.info("Send {} method to MCP server. [sessionId={}, request={}]",
Method.INITIALIZE.code(),
this.sessionId,
rpcRequest);
try (HttpClassicClientResponse<Object> exchange = request.exchange(Object.class)) {
if (exchange.statusCode() >= 200 && exchange.statusCode() < 300) {
log.info("Send {} method to MCP server successfully. [sessionId={}, statusCode={}]",
Method.INITIALIZE.code(),
this.sessionId,
exchange.statusCode());
} else {
log.error("Failed to {} MCP server. [sessionId={}, statusCode={}]",
Method.INITIALIZE.code(),
this.sessionId,
exchange.statusCode());
}
} catch (IOException e) {
throw new IllegalStateException(e);
}
this.post2McpServer(Method.INITIALIZE, schema, (request, currentId) -> {
this.sessionId = request.queries()
.first("session_id")
.orElseThrow(() -> new IllegalStateException("The session_id cannot be empty."));
this.responseConsumers.put(currentId, this::initializedMcpServer);
});
}

private void initializedMcpServer(JsonRpc.Response<Long> response) {
Expand Down Expand Up @@ -282,33 +240,11 @@ public List<Tool> getTools() {
if (this.isNotInitialized()) {
throw new IllegalStateException("MCP client is not initialized. Please wait a moment.");
}
HttpClassicClientRequest request =
this.client.createRequest(HttpRequestMethod.POST, this.baseUri + this.messageEndpoint);
long currentId = this.getNextId();
this.responseConsumers.put(currentId, this::getTools0);
this.pendingRequests.put(currentId, true);
JsonRpc.Request<Long> rpcRequest = JsonRpc.createRequest(currentId, Method.TOOLS_LIST.code());
request.entity(Entity.createObject(request, rpcRequest));
log.info("Send {} method to MCP server. [sessionId={}, request={}]",
Method.TOOLS_LIST.code(),
this.sessionId,
rpcRequest);
try (HttpClassicClientResponse<Object> exchange = request.exchange(Object.class)) {
if (exchange.statusCode() >= 200 && exchange.statusCode() < 300) {
log.info("Send {} method to MCP server successfully. [sessionId={}, statusCode={}]",
Method.TOOLS_LIST.code(),
this.sessionId,
exchange.statusCode());
} else {
log.error("Failed to {} MCP server. [sessionId={}, statusCode={}]",
Method.TOOLS_LIST.code(),
this.sessionId,
exchange.statusCode());
}
} catch (IOException e) {
throw new IllegalStateException(e);
}
while (this.pendingRequests.get(currentId)) {
long requestId = this.post2McpServer(Method.TOOLS_LIST, null, (request, currentId) -> {
this.responseConsumers.put(currentId, this::getTools0);
this.pendingRequests.put(currentId, true);
});
while (this.pendingRequests.get(requestId)) {
ThreadUtils.sleep(100);
}
synchronized (this.toolsLock) {
Expand Down Expand Up @@ -340,38 +276,16 @@ public Object callTool(String name, Map<String, Object> arguments) {
if (this.isNotInitialized()) {
throw new IllegalStateException("MCP client is not initialized. Please wait a moment.");
}
HttpClassicClientRequest request =
this.client.createRequest(HttpRequestMethod.POST, this.baseUri + this.messageEndpoint);
long currentId = this.getNextId();
this.responseConsumers.put(currentId, this::callTools0);
this.pendingRequests.put(currentId, true);
JsonRpc.Request<Long> rpcRequest = JsonRpc.createRequest(currentId,
Method.TOOLS_CALL.code(),
MapBuilder.<String, Object>get().put("name", name).put("arguments", arguments).build());
request.entity(Entity.createObject(request, rpcRequest));
log.info("Send {} method to MCP server. [sessionId={}, request={}]",
Method.TOOLS_CALL.code(),
this.sessionId,
rpcRequest);
try (HttpClassicClientResponse<Object> exchange = request.exchange(Object.class)) {
if (exchange.statusCode() >= 200 && exchange.statusCode() < 300) {
log.info("Send {} method to MCP server successfully. [sessionId={}, statusCode={}]",
Method.TOOLS_CALL.code(),
this.sessionId,
exchange.statusCode());
} else {
log.error("Failed to {} MCP server. [sessionId={}, statusCode={}]",
Method.TOOLS_CALL.code(),
this.sessionId,
exchange.statusCode());
}
} catch (IOException e) {
throw new IllegalStateException(e);
}
while (this.pendingRequests.get(currentId)) {
long requestId = this.post2McpServer(Method.TOOLS_CALL,
MapBuilder.<String, Object>get().put("name", name).put("arguments", arguments).build(),
(request, currentId) -> {
this.responseConsumers.put(currentId, this::callTools0);
this.pendingRequests.put(currentId, true);
});
while (this.pendingRequests.get(requestId)) {
ThreadUtils.sleep(100);
}
return this.pendingResults.get(currentId);
return this.pendingResults.get(requestId);
}

private void callTools0(JsonRpc.Response<Long> response) {
Expand Down Expand Up @@ -400,6 +314,37 @@ private void callTools0(JsonRpc.Response<Long> response) {
this.pendingRequests.put(response.id(), false);
}

private long post2McpServer(Method method, Object requestParams,
BiConsumer<HttpClassicClientRequest, Long> requestConsumer) {
HttpClassicClientRequest request =
this.client.createRequest(HttpRequestMethod.POST, this.baseUri + this.messageEndpoint);
long currentId = this.getNextId();
if (requestConsumer != null) {
requestConsumer.accept(request, currentId);
}
JsonRpc.Request<Long> rpcRequest = JsonRpc.createRequest(currentId, method.code(), requestParams);
request.entity(Entity.createObject(request, rpcRequest));
log.info("Send {} method to MCP server. [sessionId={}, request={}]", method.code(), this.sessionId, rpcRequest);
try (HttpClassicClientResponse<Object> exchange = request.exchange(Object.class)) {
if (exchange.statusCode() >= 200 && exchange.statusCode() < 300) {
log.info("Send {} method to MCP server successfully. [sessionId={}, statusCode={}]",
method.code(),
this.sessionId,
exchange.statusCode());
} else {
log.error("Failed to {} MCP server. [sessionId={}, statusCode={}]",
method.code(),
this.sessionId,
exchange.statusCode());
}
} catch (IOException e) {
throw new IllegalStateException(StringUtils.format("Failed to {0} MCP server. [sessionId={1}]",
method.code(),
this.sessionId), e);
}
return currentId;
}

private long getNextId() {
long tmpId = this.id.getAndIncrement();
if (tmpId < 0) {
Expand All @@ -422,10 +367,10 @@ private boolean waitInitialized() {
return true;
}
try {
this.initializedLock.wait();
this.initializedLock.wait(60_000L);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new IllegalStateException(e);
throw new IllegalStateException("Failed to initialize.", e);
}
}
return this.initialized;
Expand Down