utils.py

"""通用的工具函式"""
import os
import hashlib
from pathlib import Path

ALLOWED_EXTENSIONS = {'pdf', 'png', 'jpg', 'jpeg', 'docx', 'pptx', 'zip', 'md', 'markdown'}

def allowed_file(filename):
    """檢查檔案副檔名是否允許"""
    return '.' in filename and \
           filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS

def get_file_extension(filename):
    """獲取檔案副檔名"""
    if '.' in filename:
        return filename.rsplit('.', 1)[1].lower()
    return ''

def calculate_file_hash(file_path):
    """計算檔案的 SHA256 雜湊值"""
    sha256_hash = hashlib.sha256()
    with open(file_path, "rb") as f:
        # 讀取區塊以處理大型檔案
        for byte_block in iter(lambda: f.read(4096), b""):
            sha256_hash.update(byte_block)
    return sha256_hash.hexdigest()

def ensure_upload_dir(directory):
    """確保上傳目錄存在"""
    if not os.path.exists(directory):
        os.makedirs(directory)

def get_file_size(file_path):
    """獲取檔案大小（字節）"""
    return os.path.getsize(file_path)