Universal_File_Converter/validators.py at main · sumedhmhatre01/Universal_File_Converter · GitHub

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"""
====================================================
Universal File Converter
File Validation Module
====================================================
"""

from __future__ import annotations

from pathlib import Path
from typing import BinaryIO

from PIL import Image
from pypdf import PdfReader

from config import (
    ALLOWED_EXTENSIONS,
    MAX_FILE_SIZE_BYTES,
)


class FileValidator:
    """
    Handles validation of uploaded files.
    """

    @staticmethod
    def sanitize_filename(filename: str) -> str:
        """
        Return only the safe filename.
        """
        return Path(filename).name

    @staticmethod
    def validate_extension(filename: str) -> bool:
        """
        Check whether the file extension is supported.
        """
        extension = Path(filename).suffix.lower()
        return extension in ALLOWED_EXTENSIONS

    @staticmethod
    def validate_size(file: BinaryIO) -> bool:
        """
        Validate uploaded file size.
        """
        current_position = file.tell()

        file.seek(0, 2)
        size = file.tell()

        file.seek(current_position)

        return size <= MAX_FILE_SIZE_BYTES

    @staticmethod
    def validate_image(file: BinaryIO) -> bool:
        """
        Validate image integrity.
        """
        try:
            file.seek(0)
            img = Image.open(file)
            img.verify()
            file.seek(0)
            return True

        except Exception:
            file.seek(0)
            return False

    @staticmethod
    def validate_pdf(file: BinaryIO) -> bool:
        """
        Validate PDF integrity.
        """
        try:
            file.seek(0)
            PdfReader(file)
            file.seek(0)
            return True

        except Exception:
            file.seek(0)
            return False

    @staticmethod
    def validate_text(file: BinaryIO) -> bool:
        """
        Validate text file.
        """
        try:
            file.seek(0)
            file.read().decode("utf-8")
            file.seek(0)
            return True

        except Exception:
            file.seek(0)
            return False

    @staticmethod
    def validate(file: BinaryIO, filename: str) -> tuple[bool, str]:
        """
        Perform complete validation.
        Returns:
            (success, message)
        """

        if not FileValidator.validate_extension(filename):
            return False, "Unsupported file format."

        if not FileValidator.validate_size(file):
            return False, "File exceeds the maximum allowed size."

        extension = Path(filename).suffix.lower()

        if extension in (".jpg", ".jpeg", ".png", ".webp", ".bmp", ".tiff"):
            if not FileValidator.validate_image(file):
                return False, "Corrupted image file."

        elif extension == ".pdf":
            if not FileValidator.validate_pdf(file):
                return False, "Corrupted PDF file."

        elif extension == ".txt":
            if not FileValidator.validate_text(file):
                return False, "Invalid text file."

        return True, "Validation successful."