app.py

import torch
import torchvision.transforms as T
import torch.nn.functional as F
from torchvision import models
import torch.nn as nn

import numpy as np

from PIL import Image
from fastapi import FastAPI, UploadFile, File
from fastapi.responses import JSONResponse
import uvicorn
from fastapi.middleware.cors import CORSMiddleware

device = torch.device('cpu')

model = models.vgg16()
model.classifier[6] = nn.Linear(4096, 2)
model.load_state_dict(torch.load('model_vgg16.pth' , map_location=device))

model.eval()

transform = T.Compose([
    T.Resize((224, 224)),
    T.ToTensor(),
    T.Normalize(mean=(0.485, 0.456, 0.406), std=(0.229, 0.224, 0.225),)
])

app = FastAPI()

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"], 
    allow_headers=["*"],
)

def background2white(image) :
    arr = np.asarray(image)
    
    if arr.ndim == 3 and arr.shape[-1]==4 :
        white_background = Image.new("RGB", image.size, (255, 255, 255))
        white_background.paste(image, (0, 0), image)
        return white_background
    else : 
        return image

@app.post("/predict/")
async def predict(file: UploadFile = File(...)):
    image = Image.open(file.file)
    
    image = background2white(image).convert("RGB")
    
    # image.save('web/backend/input.jpg')
    
    print(image.size)
    print()
    image = transform(image)
    image = image.unsqueeze(0) 
    
    print(image.size)
    
    with torch.no_grad():
        output = model(image)
    
    print(output)
    
    _, predicted = torch.max(output, 1)
    
    predicted_class = predicted.item()
    
    probabilities = F.softmax(output[0] , dim=0)
    probabilities = probabilities.tolist()
    
    print(probabilities)
    
    return JSONResponse([predicted_class , probabilities[0] , probabilities[1] , output.tolist()])

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)