Skip to content

Commit 0a4644b

Browse files
xuehuitian45xuehuitian45
committed
feat(core):Add A2A Remote Agent Client
1 parent 4ca8422 commit 0a4644b

File tree

5 files changed

+603
-0
lines changed

5 files changed

+603
-0
lines changed

‎spring-ai-alibaba-graph-core/pom.xml‎

Lines changed: 17 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -40,9 +40,26 @@
4040
<properties>
4141
<testcontainers.version>1.19.3</testcontainers.version>
4242
<httpclient.version>4.5.14</httpclient.version>
43+
<a2a-sdk.version>0.2.5</a2a-sdk.version>
4344
</properties>
4445

4546
<dependencies>
47+
<dependency>
48+
<groupId>io.github.a2asdk</groupId>
49+
<artifactId>a2a-java-reference-server</artifactId>
50+
<version>${a2a-sdk.version}</version>
51+
</dependency>
52+
<dependency>
53+
<groupId>io.github.a2asdk</groupId>
54+
<artifactId>a2a-java-sdk-server-common</artifactId>
55+
<version>${a2a-sdk.version}</version>
56+
</dependency>
57+
<dependency>
58+
<groupId>io.github.a2asdk</groupId>
59+
<artifactId>a2a-java-sdk-client</artifactId>
60+
<version>${a2a-sdk.version}</version>
61+
</dependency>
62+
4663
<dependency>
4764
<groupId>org.springframework.ai</groupId>
4865
<artifactId>spring-ai-commons</artifactId>

‎spring-ai-alibaba-graph-core/src/main/java/com/alibaba/cloud/ai/graph/agent/a2a/A2aNode.java‎

Lines changed: 215 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,215 @@
1+
/*
2+
* Licensed to the Apache Software Foundation (ASF) under one or more
3+
* contributor license agreements. See the NOTICE file distributed with
4+
* this work for additional information regarding copyright ownership.
5+
* The ASF licenses this file to You under the Apache License, Version 2.0
6+
* (the "License"); you may not use this file except in compliance with
7+
* the License. You may obtain a copy of the License at
8+
*
9+
* http://www.apache.org/licenses/LICENSE-2.0
10+
*
11+
* Unless required by applicable law or agreed to in writing, software
12+
* distributed under the License is distributed on an "AS IS" BASIS,
13+
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14+
* See the License for the specific language governing permissions and
15+
* limitations under the License.
16+
*/
17+
package com.alibaba.cloud.ai.graph.agent.a2a;
18+
19+
import com.alibaba.cloud.ai.graph.OverAllState;
20+
import com.alibaba.cloud.ai.graph.action.NodeAction;
21+
import com.alibaba.fastjson.JSON;
22+
import com.fasterxml.jackson.databind.ObjectMapper;
23+
import io.a2a.spec.AgentCard;
24+
import org.apache.http.HttpEntity;
25+
import org.apache.http.client.methods.CloseableHttpResponse;
26+
import org.apache.http.client.methods.HttpPost;
27+
import org.apache.http.entity.ContentType;
28+
import org.apache.http.entity.StringEntity;
29+
import org.apache.http.impl.client.CloseableHttpClient;
30+
import org.apache.http.impl.client.HttpClients;
31+
import org.apache.http.util.EntityUtils;
32+
33+
import java.util.HashMap;
34+
import java.util.List;
35+
import java.util.Map;
36+
import java.util.UUID;
37+
38+
public class A2aNode implements NodeAction {
39+
40+
private final AgentCard agentCard;
41+
42+
private final String inputKeyFromParent;
43+
44+
private final String outputKeyToParent;
45+
46+
private final boolean streaming;
47+
48+
private final ObjectMapper objectMapper = new ObjectMapper();
49+
50+
public A2aNode(AgentCard agentCard, String inputKeyFromParent, String outputKeyToParent) {
51+
this(agentCard, inputKeyFromParent, outputKeyToParent, false);
52+
}
53+
54+
public A2aNode(AgentCard agentCard, String inputKeyFromParent, String outputKeyToParent, boolean streaming) {
55+
this.agentCard = agentCard;
56+
this.inputKeyFromParent = inputKeyFromParent;
57+
this.outputKeyToParent = outputKeyToParent;
58+
this.streaming = streaming;
59+
}
60+
61+
@Override
62+
public Map<String, Object> apply(OverAllState state) throws Exception {
63+
String requestPayload = this.streaming ? buildSendStreamingMessageRequest(state, this.inputKeyFromParent)
64+
: buildSendMessageRequest(state, this.inputKeyFromParent);
65+
66+
String resultText = sendMessageToServer(this.agentCard, requestPayload);
67+
68+
Map<String, Object> resultMap = JSON.parseObject(resultText, Map.class);
69+
Map<String, Object> result = (Map<String, Object>) resultMap.get("result");
70+
71+
String responseText = extractResponseText(result);
72+
return Map.of(this.outputKeyToParent, responseText);
73+
}
74+
75+
private String extractResponseText(Map<String, Object> result) {
76+
if (result.containsKey("artifacts")) {
77+
List<Object> artifacts = (List<Object>) result.get("artifacts");
78+
StringBuilder responseBuilder = new StringBuilder();
79+
for (Object artifact : artifacts) {
80+
if (artifact instanceof Map) {
81+
List<Object> parts = (List<Object>) ((Map<String, Object>) artifact).get("parts");
82+
for (Object part : parts) {
83+
if (part instanceof Map) {
84+
String text = (String) ((Map<String, Object>) part).get("text");
85+
if (text != null) {
86+
responseBuilder.append(text);
87+
}
88+
}
89+
}
90+
}
91+
}
92+
return responseBuilder.toString();
93+
} else {
94+
List<Object> parts = (List<Object>) result.get("parts");
95+
Map<String, Object> lastPart = (Map<String, Object>) parts.get(parts.size() - 1);
96+
return (String) lastPart.get("text");
97+
}
98+
}
99+
100+
/**
101+
* Build the JSON-RPC request payload to send to the A2A server.
102+
*
103+
* @param state Parent state
104+
* @param inputKey Input key to retrieve user input from the state
105+
* @return JSON string payload (e.g., JSON-RPC params)
106+
*/
107+
private String buildSendMessageRequest(OverAllState state, String inputKey) {
108+
Object textValue = state.value(inputKey)
109+
.orElseThrow(() -> new IllegalArgumentException("Input key '" + inputKey + "' not found in state: " + state));
110+
String text = String.valueOf(textValue);
111+
112+
String id = UUID.randomUUID().toString();
113+
String messageId = UUID.randomUUID().toString().replace("-", "");
114+
115+
Map<String, Object> part = Map.of("kind", "text", "text", text);
116+
117+
Map<String, Object> message = new HashMap<>();
118+
message.put("kind", "message");
119+
message.put("messageId", messageId);
120+
message.put("parts", List.of(part));
121+
message.put("role", "user");
122+
123+
Map<String, Object> params = Map.of("message", message);
124+
125+
Map<String, Object> root = new HashMap<>();
126+
root.put("id", id);
127+
root.put("jsonrpc", "2.0");
128+
root.put("method", "message/send");
129+
root.put("params", params);
130+
131+
try {
132+
return objectMapper.writeValueAsString(root);
133+
} catch (Exception e) {
134+
throw new IllegalStateException("Failed to build JSON-RPC payload", e);
135+
}
136+
}
137+
138+
/**
139+
* Build the JSON-RPC streaming request payload (method: message/stream).
140+
*
141+
* @param state Parent state
142+
* @param inputKey Input key to retrieve user input from the state
143+
* @return JSON string payload for streaming
144+
*/
145+
private String buildSendStreamingMessageRequest(OverAllState state, String inputKey) {
146+
Object textValue = state.value(inputKey)
147+
.orElseThrow(() -> new IllegalArgumentException("Input key '" + inputKey + "' not found in state: " + state));
148+
String text = String.valueOf(textValue);
149+
150+
String id = UUID.randomUUID().toString();
151+
String messageId = UUID.randomUUID().toString().replace("-", "");
152+
153+
Map<String, Object> part = Map.of("kind", "text", "text", text);
154+
155+
Map<String, Object> message = new HashMap<>();
156+
message.put("kind", "message");
157+
message.put("messageId", messageId);
158+
message.put("parts", List.of(part));
159+
message.put("role", "user");
160+
161+
Map<String, Object> params = Map.of("message", message);
162+
163+
Map<String, Object> root = new HashMap<>();
164+
root.put("id", id);
165+
root.put("jsonrpc", "2.0");
166+
root.put("method", "message/stream");
167+
root.put("params", params);
168+
169+
try {
170+
return objectMapper.writeValueAsString(root);
171+
} catch (Exception e) {
172+
throw new IllegalStateException("Failed to build JSON-RPC streaming payload", e);
173+
}
174+
}
175+
176+
/**
177+
* Send the request to the remote A2A server and return the non-streaming response.
178+
*
179+
* @param agentCard Agent card (source for server URL/metadata)
180+
* @param requestPayload JSON string payload built by buildSendMessageRequest
181+
* @return Response body as string
182+
*/
183+
private String sendMessageToServer(AgentCard agentCard, String requestPayload) throws Exception {
184+
String baseUrl = resolveAgentBaseUrl(agentCard);
185+
if (baseUrl == null || baseUrl.isBlank()) {
186+
throw new IllegalStateException("AgentCard.url is empty");
187+
}
188+
189+
try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
190+
HttpPost post = new HttpPost(baseUrl);
191+
post.setHeader("Content-Type", "application/json");
192+
post.setEntity(new StringEntity(requestPayload, ContentType.APPLICATION_JSON));
193+
194+
try (CloseableHttpResponse response = httpClient.execute(post)) {
195+
int statusCode = response.getStatusLine().getStatusCode();
196+
if (statusCode != 200) {
197+
throw new IllegalStateException("HTTP request failed, status: " + statusCode);
198+
}
199+
HttpEntity entity = response.getEntity();
200+
if (entity == null) {
201+
throw new IllegalStateException("Empty HTTP entity");
202+
}
203+
return EntityUtils.toString(entity, "UTF-8");
204+
}
205+
}
206+
}
207+
208+
/**
209+
* Resolve base URL from the AgentCard.
210+
*/
211+
private String resolveAgentBaseUrl(AgentCard agentCard) {
212+
return agentCard.url();
213+
}
214+
215+
}

0 commit comments

Comments
 (0)