server.py

"""Server that will listen for GET and POST requests from the client."""

import time
from typing import List

from common import FILTERS_PATH, SERVER_TMP_PATH
from fastapi import FastAPI, File, Form, UploadFile
from fastapi.responses import JSONResponse, Response
from pydantic import BaseModel
from concrete.ml.deployment import FHEModelServer


def get_server_file_path(name, user_id, filter_name):
    """Get the correct temporary file path for the server.

    Args:
        name (str): The desired file name.
        user_id (int): The current user's ID.
        filter_name (str): The filter chosen by the user

    Returns:
        pathlib.Path: The file path.
    """
    return SERVER_TMP_PATH / f"{name}_{filter_name}_{user_id}"


class FilterRequest(BaseModel):
    filter: str


# Initialize an instance of FastAPI
app = FastAPI()

# Define the default route
@app.get("/")
def root():
    return {"message": "Welcome to Your Image FHE Filter Server!"}


@app.post("/send_input")
def send_input(
    user_id: str = Form(),
    filter: str = Form(),
    files: List[UploadFile] = File(),
):
    """Send the inputs to the server."""
    # Retrieve the encrypted input image and the evaluation key paths
    encrypted_image_path = get_server_file_path("encrypted_image", filter, user_id)
    evaluation_key_path = get_server_file_path("evaluation_key", filter, user_id)
    
    # Write the files using the above paths
    with encrypted_image_path.open("wb") as encrypted_image, evaluation_key_path.open(
        "wb"
    ) as evaluation_key:
        encrypted_image.write(files[0].file.read())
        evaluation_key.write(files[1].file.read())


@app.post("/run_fhe")
def run_fhe(
    user_id: str = Form(),
    filter: str = Form(),
):
    """Execute the filter on the encrypted input image using FHE."""
    # Retrieve the encrypted input image and the evaluation key paths
    encrypted_image_path = get_server_file_path("encrypted_image", filter, user_id)
    evaluation_key_path = get_server_file_path("evaluation_key", filter, user_id)

    # Read the files using the above paths
    with encrypted_image_path.open("rb") as encrypted_image_file, evaluation_key_path.open(
        "rb"
    ) as evaluation_key_file:
        encrypted_image = encrypted_image_file.read()
        evaluation_key = evaluation_key_file.read()

    # Load the FHE server
    fhe_server = FHEModelServer(FILTERS_PATH / f"{filter}/deployment")

    # Run the FHE execution
    start = time.time()
    encrypted_output_image = fhe_server.run(encrypted_image, evaluation_key)
    fhe_execution_time = round(time.time() - start, 2)

    # Retrieve the encrypted output image path
    encrypted_output_path = get_server_file_path("encrypted_output", filter, user_id)

    # Write the file using the above path
    with encrypted_output_path.open("wb") as encrypted_output:
        encrypted_output.write(encrypted_output_image)

    return JSONResponse(content=fhe_execution_time)


@app.post("/get_output")
def get_output(
    user_id: str = Form(),
    filter: str = Form(),
):
    """Retrieve the encrypted output image."""
    # Retrieve the encrypted output image path
    encrypted_output_path = get_server_file_path("encrypted_output", filter, user_id)

    # Read the file using the above path
    with encrypted_output_path.open("rb") as encrypted_output_file:
        encrypted_output = encrypted_output_file.read()

    return Response(encrypted_output)