example_protect.py

import aspose.pdf as ap
import sys
from os import path

sys.path.append(path.join(path.dirname(__file__), ".."))

from config import set_license, initialize_data_dir


def encrypt_password(infile, outfile):
    """
    Encrypt PDF with password and permissions.

    Args:
        infile (str): Input PDF filename
        outfile (str): Output PDF filename

    Returns:
        None

    Example:
        encrypt_password("sample.pdf", "sample_protected.pdf")

    Note:
        Uses AES 128-bit encryption. Allows screen readers, forbids all other operations.
        User password: "userpassword", Owner password: "ownerpassword".
    """
    document = ap.Document(infile)
    document_privilege = ap.facades.DocumentPrivilege.forbid_all
    document_privilege.allow_screen_readers = True

    document.encrypt(
        "userpassword",
        "ownerpassword",
        document_privilege,
        ap.CryptoAlgorithm.AESx128,
        False,
    )
    document.save(outfile)


def encrypt_pdf_file(infile, outfile):
    """
    Encrypt PDF with full permissions.

    Args:
        infile (str): Input PDF filename
        outfile (str): Output PDF filename

    Returns:
        None

    Example:
        encrypt_pdf_file("sample.pdf", "sample_protected.pdf")

    Note:
        Uses RC4 128-bit encryption with allow_all privileges.
    """
    document = ap.Document(infile)
    document.encrypt(
        "userpassword",
        "ownerpassword",
        ap.facades.DocumentPrivilege.allow_all,
        ap.CryptoAlgorithm.RC4x128,
        False,
    )
    document.save(outfile)


def decrypt_pdf_file(infile, outfile):
    """
    Decrypt password-protected PDF.

    Args:
        infile (str): Input encrypted PDF filename
        outfile (str): Output decrypted PDF filename

    Returns:
        None

    Example:
        decrypt_pdf_file("sample_protected.pdf", "sample_unprotected.pdf")

    Note:
        Requires user password to open document.
    """
    document = ap.Document(infile, "userpassword")
    document.decrypt()
    document.save(outfile)


def change_password(infile, outfile):
    """
    Change user and owner passwords.

    Args:
        infile (str): Input PDF filename
        outfile (str): Output PDF filename

    Returns:
        None

    Example:
        change_password("sample_protected.pdf", "sample_changepassword.pdf")

    Note:
        Changes from ownerpassword to newuser/newowner.
    """
    document = ap.Document(infile, "ownerpassword")
    document.change_passwords("ownerpassword", "newuser", "newowner")
    document.save(outfile)


def determine_correct_password_from_list(infile):
    """
    Test multiple passwords to find correct one.

    Args:
        infile (str): Input encrypted PDF filename

    Returns:
        None

    Example:
        determine_correct_password_from_list("sample_protected.pdf")

    Note:
        Tries passwords: test, test1, test2, test3, userpassword.
        Prints page count if password is correct.
    """
    info = ap.facades.PdfFileInfo(infile)
    print(f"File is password protected {info.is_encrypted}")

    passwords = "test", "test1", "test2", "test3", "userpassword"

    for password in passwords:
        try:
            document = ap.Document(infile, password)
            count = len(document.pages)
            if count > 0:
                print(f"Password '{password}' is correct. Number of pages in document: {count}")
        except RuntimeError as ex:
            if "InvalidPasswordException" in str(type(ex)) or "InvalidPasswordException" in str(ex):
                print(f"Wrong password: {password}")
            else:
                template = "An exception of type {0} occurred. Arguments:\n{1!r}"
                message = template.format(type(ex).__name__, ex.args)
                print(message)


def run_all_examples(data_dir=None, license_path=None):
    """Run Protect Document examples and report status.
    Args:
        data_dir (str, optional): Input/output directory override.
        license_path (str, optional): Path to Aspose.PDF license file.
    Returns:
        None
    """

    set_license(license_path)
    input_dir, output_dir = initialize_data_dir(data_dir)

    examples = [
        (
            "Encrypt with password",
            encrypt_password,
            "sample3.pdf",
            "sample_protected.pdf",
        ),
        ("Encrypt PDF file", encrypt_pdf_file, "sample3.pdf", "sample_protected.pdf"),
        (
            "Change password",
            change_password,
            "sample_protected.pdf",
            "sample_changepassword.pdf",
        ),
        (
            "Decrypt PDF",
            decrypt_pdf_file,
            "sample_protected.pdf",
            "sample_unprotected.pdf",
        ),
        (
            "Determine password",
            determine_correct_password_from_list,
            "sample_protected.pdf",
            None,
        ),
    ]

    for name, func, infile, outfile in examples:
        try:
            input_file = path.join(input_dir, infile)
            if outfile:
                output_file = path.join(output_dir, outfile)
                func(input_file, output_file)
            else:
                func(input_file)
            print(f"✅ Success: {name}")
        except Exception as e:
            print(f"❌ Failed: {name} - {e}")


if __name__ == "__main__":
    run_all_examples()