Run a particular Python script as a Service

Question

I've got a Python 3 script going that will overlay a particular transparent PDF file on top of another for the purpose of watermarking.

Copying and pasting the file location of each PDF into the script each time I want to watermark something is a bit of a headache though. The whole thing is not very flexible despite its great power.

from pdfrw import PdfReader, PdfWriter, PageMerge

ipdf = PdfReader("/users/me/Desktop/meetingminutes.pdf")
wpdf = PdfReader("/users/me/Desktop/private.pdf")

wmark = PageMerge().add(wpdf.pages[0])[0]

for page in ipdf.pages:
    PageMerge(page).add(wmark).render()

PdfWriter().write('/users/me/Desktop/meetingminutes.pdf', ipdf)

I would ideally like to be able to right click on a given PDF file in Finder and apply the watermark script to it as a service.

I've done a little bit of tinkering already but the most I've been able to figure out on my own is that I need to run the script as it is (right now) I can make an Automator App with the "Run AppleScript" droplet as the first step.

on run {input, parameters}
    do shell script "/usr/local/bin/python3 /users/me/Desktop/script.py

    return input
end run

It'd be wonderful to scale this up to work on any given PDF. The actual "watermark" image PDF would be at a fixed location on the hard drive and the files on which the service is applied would not be renamed or moved/copied elsewhere (ideally).

Have you tried reading This Post on SO? Then integrate your script, and ask for input at the beginning of the Automator script, as well as what output file should be. — bret7600, Sep 11 '17 at 18:26
I tried using (for example) "inFile = sys.argv[1]" etc in my script but I always get an "IndexError: list index out of range" error. — William Lombard, Sep 11 '17 at 18:50

score 1 · Answer 1 · answered Jan 04 '19 at 12:37

In Automator, use the "Run Shell Script" action. Normally, you would set the shell drop-down list value to "/usr/bin/python", to use the built-in python 2.7. However, if you select a unix shell, but make sure that your script contains "#! /usr/bin/ env python", or an explicit path to your python3 installation, then it should work.

If you select the other drop-down list "Pass input" to "as arguments", then you can get the filenames of your selected items from sys.argv().

Note that Automator already comes with a watermark action that lets you put one PDF on top of another. (It's also a python script, if you dig deep enough into /System/Library/Automator/)

Run a particular Python script as a Service

1 Answers1