Check whether a PDF-File is valid with Python

Question

I get a File via a HTTP-Upload and need to be sure its a pdf-file. Programing Language is Python, but this should not matter.

I thought of the follow

Answer 1

Here is a solution using pdfminersix, which can be installed with pip install pdfminer.six:

from pdfminer.high_level import extract_text

def is_pdf(path_to_file):
    try:
        extract_text(path_to_file)
        return True
    except:
        return False

You can also use filetype (pip install filetype):

import filetype

def is_pdf(path_to_file):
    return filetype.guess(path_to_file).mime == 'application/pdf'

Neither of these solutions is ideal.

1. The problem with the filetype solution is that it doesn't tell you if the PDF itself is readable or not. It will tell you if the file is a PDF, but it could be a corrupt PDF.
2. The pdfminer solution should only return True if the PDF is actually readable. But it is a big library and seems like overkill for such a simple function.

I've started another thread here asking how to check if a file is a valid PDF without using a library (or using a smaller one).