chore: initial import of standalone agentscope project

examples/agent/a2ui_agent/samples/client/lit/shell/middleware/a2a.ts

@@ -0,0 +1,153 @@
+/*
+ Copyright 2025 Google LLC
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+      https://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ */
+
+import { IncomingMessage, ServerResponse } from "http";
+import { Plugin, ViteDevServer } from "vite";
+import { A2AClient } from "@a2a-js/sdk/client";
+import {
+  MessageSendParams,
+  Part,
+  SendMessageSuccessResponse,
+  Task,
+} from "@a2a-js/sdk";
+import { v4 as uuidv4 } from "uuid";
+
+const A2AUI_MIME_TYPE = "application/json+a2aui";
+
+const fetchWithCustomHeader: typeof fetch = async (url, init) => {
+  const headers = new Headers(init?.headers);
+  headers.set("X-A2A-Extensions", "https://a2ui.org/a2a-extension/a2ui/v0.8");
+
+  const newInit = { ...init, headers };
+  return fetch(url, newInit);
+};
+
+const isJson = (str: string) => {
+  try {
+    const parsed = JSON.parse(str);
+    return (
+      typeof parsed === "object" && parsed !== null && !Array.isArray(parsed)
+    );
+  } catch (err) {
+    console.warn(err);
+    return false;
+  }
+};
+
+let client: A2AClient | null = null;
+const createOrGetClient = async () => {
+  if (!client) {
+    // Create a client pointing to the agent's Agent Card URL.
+    client = await A2AClient.fromCardUrl(
+      "http://localhost:10002/.well-known/agent-card.json",
+      { fetchImpl: fetchWithCustomHeader }
+    );
+  }
+
+  return client;
+};
+
+export const plugin = (): Plugin => {
+  return {
+    name: "a2a-handler",
+    configureServer(server: ViteDevServer) {
+      server.middlewares.use(
+        "/a2a",
+        async (req: IncomingMessage, res: ServerResponse, next: () => void) => {
+          if (req.method === "POST") {
+            let originalBody = "";
+
+            req.on("data", (chunk) => {
+              originalBody += chunk.toString();
+            });
+
+            req.on("end", async () => {
+              let sendParams: MessageSendParams;
+
+              if (isJson(originalBody)) {
+                console.log(
+                  "[a2a-middleware] Received JSON UI event:",
+                  originalBody
+                );
+
+                const clientEvent = JSON.parse(originalBody);
+                sendParams = {
+                  message: {
+                    messageId: uuidv4(),
+                    role: "user",
+                    parts: [
+                      {
+                        kind: "data",
+                        data: clientEvent,
+                        metadata: { 'mimeType': A2AUI_MIME_TYPE },
+                      } as Part,
+                    ],
+                    kind: "message",
+                  },
+                };
+              } else {
+                console.log(
+                  "[a2a-middleware] Received text query:",
+                  originalBody
+                );
+                sendParams = {
+                  message: {
+                    messageId: uuidv4(),
+                    role: "user",
+                    parts: [
+                      {
+                        kind: "text",
+                        text: originalBody,
+                      },
+                    ],
+                    kind: "message",
+                  },
+                };
+              }
+
+              const client = await createOrGetClient();
+              const response = await client.sendMessage(sendParams);
+              if ("error" in response) {
+                console.error("Error:", response.error.message);
+                res.statusCode = 500;
+                res.setHeader("Content-Type", "application/json");
+                res.end(JSON.stringify({ error: response.error.message }));
+                return;
+              } else {
+                const result = (response as SendMessageSuccessResponse)
+                  .result as Task;
+                if (result.kind === "task") {
+                  res.statusCode = 200;
+                  res.setHeader("Content-Type", "application/json");
+                  res.end(JSON.stringify(result.status.message?.parts));
+                  return;
+                }
+              }
+
+              res.statusCode = 200;
+              res.setHeader("Content-Type", "application/json");
+              res.end(JSON.stringify([]));
+            });
+
+            return;
+          } else {
+            next();
+          }
+        }
+      );
+    },
+  };
+};

examples/agent/a2ui_agent/samples/client/lit/shell/middleware/index.ts

@@ -0,0 +1,17 @@
+/*
+ Copyright 2025 Google LLC
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+      https://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ */
+
+export * as A2AMiddleware from "./a2a.js";