Làm cách nào để sử dụng webhook và polling cho việc tạo video?

curl https://api.cometapi.com/v1/videos \
  -H "Authorization: Bearer $COMETAPI_KEY" \
  -F "model=doubao-seedance-2-0" \
  -F "prompt=A cinematic shot of a paper airplane crossing a desk"

{
  "id": "task_example",
  "task_id": "task_example",
  "object": "video",
  "model": "doubao-seedance-2-0",
  "status": "queued",
  "progress": 0,
  "created_at": 1779872000
}

curl https://api.cometapi.com/v1/videos/task_example \
  -H "Authorization: Bearer $COMETAPI_KEY"

{
  "id": "task_example",
  "object": "video",
  "model": "doubao-seedance-2-0",
  "status": "completed",
  "progress": 100,
  "completed_at": 1779872300,
  "video_url": "<generated-video-url>"
}

import express from "express";

const app = express();
app.use(express.json({ limit: "2mb" }));

app.post("/cometapi/video-webhook", async (request, response) => {
  const event = request.body;

  console.log("Task ID:", event.task_id || event.id);
  console.log("Status:", event.status);

  response.status(200).json({ received: true });
});

app.listen(3000);

{
  "task_id": "task_example",
  "status": "completed",
  "progress": 100,
  "result": {
    "video_url": "https://example.com/result.mp4"
  }
}