chore: initialize sandbox and overwrite remote content

examples/agent/a2ui_agent/samples/client/lit/contact/client.ts

@@ -0,0 +1,65 @@
+/*
+ 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 { v0_8 } from "@a2ui/lit";
+import { registerContactComponents } from "./ui/custom-components/register-components.js";
+type A2TextPayload = {
+  kind: "text";
+  text: string;
+};
+
+type A2DataPayload = {
+  kind: "data";
+  data: v0_8.Types.ServerToClientMessage;
+};
+
+type A2AServerPayload =
+  | Array<A2DataPayload | A2TextPayload>
+  | { error: string };
+
+export class A2UIClient {
+  #ready: Promise<void> = Promise.resolve();
+  get ready() {
+    return this.#ready;
+  }
+
+  async send(
+    message: v0_8.Types.A2UIClientEventMessage
+  ): Promise<v0_8.Types.ServerToClientMessage[]> {
+    const response = await fetch("/a2a", {
+      body: JSON.stringify(message),
+      method: "POST",
+    });
+
+    if (response.ok) {
+      const data = (await response.json()) as A2AServerPayload;
+      const messages: v0_8.Types.ServerToClientMessage[] = [];
+      if ("error" in data) {
+        throw new Error(data.error);
+      } else {
+        for (const item of data) {
+          if (item.kind === "text") continue;
+          messages.push(item.data);
+        }
+      }
+      return messages;
+    }
+
+    const error = (await response.json()) as { error: string };
+    throw new Error(error.error);
+  }
+}
+registerContactComponents();