Add embedded JavaScript script to a PDF document (python3)

addjstopdf.py

#!/usr/bin/env python3
# https://gist.github.com/edoz90/a441f2bdfc8c99c1999db0a3e8495fb6
# Author: notdodo
try:
    from PyPDF2 import PdfFileWriter, PdfFileReader
    import click
except ModuleNotFoundError:
    print("pip install pypdf2 click")
    import sys

    sys.exit(-1)

CONTEXT_SETTINGS = dict(help_option_names=["-h", "--help"])


def main(javascriptfile, inputpdf, outputpdf):
    outputwriter = PdfFileWriter()
    inputwriter = PdfFileReader(open(inputpdf, "rb"))

    # Read javascript
    with open(javascriptfile, "r") as jf:
        javascript = jf.read()

    # Recreate the stream from the original file
    for p in range(inputwriter.getNumPages()):
        outputwriter.addPage(inputwriter.getPage(p - 1))

    # Add JavaScript
    outputwriter.addJS(javascript)

    # Write the injected PDF file
    outputstream = open(outputpdf, "wb")
    outputwriter.write(outputstream)


@click.command(context_settings=CONTEXT_SETTINGS)
@click.option(
    "--javascriptfile",
    "-jf",
    nargs=1,
    help="File to embed",
    type=click.Path(exists=True, readable=True),
)
@click.argument(
    "inputpdf", nargs=1, type=click.Path(exists=True, readable=True)
)
@click.argument("outputpdf", nargs=1, type=click.Path(writable=True))
def cmd(javascriptfile, inputpdf, outputpdf):
    """Add embedded JavaScript to a PDF document that will
       execute automatically when the document is opened

       Example:\n
       app.alert("Hello World!");

       Reference: https://adobe.ly/2DtYoYL"""
    main(javascriptfile, inputpdf, outputpdf)


if __name__ == "__main__":
    cmd()