json-render/examples/chat/app/api/generate/route.ts

import { agent } from "@/lib/agent";
import {
  convertToModelMessages,
  createUIMessageStream,
  createUIMessageStreamResponse,
  type UIMessage,
} from "ai";
import { pipeJsonRender } from "@json-render/core";

export const maxDuration = 60;

export async function POST(req: Request) {
  const body = await req.json();
  const uiMessages: UIMessage[] = body.messages;

  if (!uiMessages || !Array.isArray(uiMessages) || uiMessages.length === 0) {
    return new Response(
      JSON.stringify({ error: "messages array is required" }),
      {
        status: 400,
        headers: { "Content-Type": "application/json" },
      },
    );
  }

  const modelMessages = await convertToModelMessages(uiMessages);
  const result = await agent.stream({ messages: modelMessages });

  const stream = createUIMessageStream({
    execute: async ({ writer }) => {
      writer.merge(pipeJsonRender(result.toUIMessageStream()));
    },
  });

  return createUIMessageStreamResponse({ stream });
}