services/file_validation.py

import re
from fastapi import UploadFile

def validate_mime_type(file: UploadFile):
	if file.content_type != "application/pdf":
		print("[!] validate_mime_type")
		return False
	return True
def validate_extension(file: UploadFile):
	if not file.filename.endswith((".pdf")):
		print("[!] validate_extension")
		return False
	return True
async def validate_magic_bytes(file: UploadFile):
	magic_bytes = await file.read(5)
	await file.seek(0)  # Reset file pointer after reading
	if magic_bytes != b"%PDF-" or len(magic_bytes) < 5:
		print("[!] validate_magic_bytes")
		return False
	return True

'''validate the uploaded file'''
async def validate_document(file: UploadFile):
	if file.file is None:
		print("[!] file is None")
		return False
	if not validate_mime_type(file):
		return False
	if not validate_extension(file):
		return False
	if not await validate_magic_bytes(file):
		return False
	return True

def sanitize_for_display(filename: str) -> str:
    # Remove any characters that are not letters, numbers, spaces, or common punctuation
    clean_name = re.sub(r'[^\w \-_.\(\)]', '', filename)

    #if it's longer than 50 chars keep the first 20 chars and the last 10
    if len(clean_name) > 50:
        clean_name = clean_name[:40] + "..." + clean_name[-10:]
        
    return clean_name.strip() or "Untitled Document.pdf"