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

Update 2020

It looks like pdfminer.six is a maintained project (the others, including the one below, seem dead).

ReportLab is another one (mistakenly marked as dead by me)

Original answer

Since apparently neither PyPdf nor ReportLab is available anymore, the current solution I found (as of 2015) is to use PyPDF2 and catch exceptions (and possibly analyze getDocumentInfo())

import PyPDF2

with open("testfile.txt", "w") as f:
    f.write("hello world!")

try:
    PyPDF2.PdfFileReader(open("testfile.txt", "rb"))
except PyPDF2.utils.PdfReadError:
    print("invalid PDF file")
else:
    pass