app.py

import torch
from torchvision import transforms, models
from art.attacks.evasion import FastGradientMethod
from art.estimators.classification import PyTorchClassifier
from PIL import Image
import numpy as np
import io
import base64
from blind_watermark import WaterMark

def load_model():
    model = models.resnet50(pretrained=False)
    num_ftrs = model.fc.in_features
    model.fc = torch.nn.Linear(num_ftrs, 10)
    
    model.load_state_dict(torch.load("model.pt", map_location=torch.device('cpu')))
    model.eval()
    return model

def process_image(inputs: dict):
    input_image = inputs["inputs"]
    eps_value = inputs.get("eps", 0.3)

    model = load_model()
    device = torch.device("cpu")
    model = model.to(device)

    criterion = torch.nn.CrossEntropyLoss()
    optimizer = torch.optim.Adam(model.parameters(), lr=0.001)

    classifier = PyTorchClassifier(
        model=model,
        loss=criterion,
        optimizer=optimizer,
        input_shape=(3, 64, 64),
        nb_classes=10,
    )

    transform = transforms.Compose([
        transforms.ToTensor(),
        transforms.Normalize(mean=[0.485, 0.456, 0.406],
                             std=[0.229, 0.224, 0.225])
    ])

    img = Image.open(io.BytesIO(base64.b64decode(input_image))).convert('RGB')
    img_tensor = transform(img).unsqueeze(0).to(device)

    attack = FastGradientMethod(estimator=classifier, eps=eps_value)
    adv_img_tensor = attack.generate(x=img_tensor.cpu().numpy())
    adv_img_tensor = torch.tensor(adv_img_tensor).to(device)

    adv_img_np = adv_img_tensor.squeeze(0).cpu().numpy()
    mean = np.array([0.485, 0.456, 0.406])
    std = np.array([0.229, 0.224, 0.225])
    adv_img_np = (adv_img_np * std[:, None, None]) + mean[:, None, None]
    adv_img_np = np.clip(adv_img_np, 0, 1)
    adv_img_np = adv_img_np.transpose(1, 2, 0)

    adv_image_pil = Image.fromarray((adv_img_np * 255).astype(np.uint8))

    wm_text = "123"
    bwm = WaterMark(password_img=123, password_wm=456)

    img_bytes = io.BytesIO()
    adv_image_pil.save(img_bytes, format='PNG')
    bwm.read_img(img_bytes)
    bwm.read_wm(wm_text, mode='str')
    
    bwm.embed(img_bytes)
    result_image = base64.b64encode(img_bytes.getvalue()).decode('utf-8')

    return {"image": result_image}