Render ảnh try-on từ một Django worker

# store/models.py
from django.db import models

class TryOn(models.Model):
    product = models.ForeignKey("Product", on_delete=models.CASCADE)
    generation_id = models.CharField(max_length=64, db_index=True)
    status = models.CharField(max_length=16, default="processing")
    output_url = models.URLField(blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

# store/tasks.py
from celery import shared_task

@shared_task(bind=True, max_retries=3)
def run_try_on(self, try_on_id):
    import os, requests
    
    res = requests.post(
        "https://api.photta.app/api/v1/tryon/apparel",
        headers={"Authorization": f"Bearer {os.environ['PHOTTA_API_KEY']}"},
        json={
          "product_type": "top",
          "product_images": [
            "https://cdn.yourstore.com/products/shirt-front.jpg"
          ],
          "product_back_image": "https://cdn.yourstore.com/products/shirt-back.jpg",
          "product_category": "t_shirt",
          "mannequin_id": "mnk_f3a9b1",
          "pose_id": "pose_c2d4e5",
          "background": "https://cdn.yourstore.com/backgrounds/studio-loft.jpg",
          "lock_background": True,
          "resolution": "2K",
          "aspect_ratio": "3:4",
          "body_size": "M",
          "expression": "neutral",
          "user_instruction": "Keep the collar pattern crisp and centered."
        },
    )
    data = res.json()["data"]  # data["id"], data["status"]
    
    import time
    
    def wait_for(job_id):
        for _ in range(120):
            res = requests.get(f"https://api.photta.app/api/v1/tryon/apparel/{job_id}", headers={"Authorization": f"Bearer {os.environ['PHOTTA_API_KEY']}"})
            data = res.json()["data"]
            if data["status"] == "completed":
                return data["output_url"]
            if data["status"] == "failed":
                raise RuntimeError(data.get("error_message", "generation failed"))
            time.sleep(3)
        raise TimeoutError("timed out after 6 minutes")

try:
    photta("POST", "/tryon/apparel", json={
      "product_type": "top",
      "product_images": [
        "https://cdn.yourstore.com/products/shirt-front.jpg"
      ],
      "product_back_image": "https://cdn.yourstore.com/products/shirt-back.jpg",
      "product_category": "t_shirt",
      "mannequin_id": "mnk_f3a9b1",
      "pose_id": "pose_c2d4e5",
      "background": "https://cdn.yourstore.com/backgrounds/studio-loft.jpg",
      "lock_background": True,
      "resolution": "2K",
      "aspect_ratio": "3:4",
      "body_size": "M",
      "expression": "neutral",
      "user_instruction": "Keep the collar pattern crisp and centered."
    })
except PhottaError as e:
    if e.status == 402:
        print("insufficient_credits_error: top up before retrying")
    elif e.status == 429:
        time.sleep(int(e.retry_after or 30))
    else:
        raise

# store/tasks.py — the output URL delivers one job; your storage keeps it
import requests
from django.core.files.base import ContentFile

def persist(try_on, output_url):
    body = requests.get(output_url, timeout=60).content
    try_on.product.gallery.save(f"{try_on.generation_id}.jpg", ContentFile(body))
    try_on.status, try_on.output_url = "completed", output_url
    try_on.save(update_fields=["status", "output_url"])