If you're familiar with bash, the process of "apply something to a lot of files" is trivial: just make the "something" either a shell function
something() { infile="$1" outfile="$2" dothefirststep "${infile}" dothesecondstep -o "${outfile}" … }
or put the something in a shell or perl script file (say, something.sh or something.pl), make it executable, and then run each file matching a glob through it:
for file in *.pdf; do something "${file}" "${file%.pdf}-signed.pdf"; done
Now, how does one add watermarks? Never done this myself, because I consider it a nuisance to the user that should not be done, but OK, it's your job, can't tell you what to do. How you'd do it:
Preparation:
- Get your certificate in PEM format and your private signing key (matching that certificate, of course) in PEM format
- take your watermark images and make page-sized PDFs out of them, with transparent background. Inkscape is an easy way to create such single-page PDFs.
- Write a script to put a watermark atop of each page. I'd probably use Python and the PyPDF2 library. The following is top-of-my-head, untested code. You'll probably have to fiddle with it until it works (I call it
watermark.py:
#!/usr/bin/env python3 from sys import argv from PyPDF2 import PdfReader, PdfWriter with open(argv[1], "rb") as in_file, open(argv[2], "rb") as wtrmrk_file: out = PdfWriter() document = PdfReader(in_file) watermark = PdfReader(wtrmrk_file).pages[0] for page in document.pages: page.merge_page(watermark) out.add_page(page) with open(argv[3], "wb") as out_file: out.write(out_file)
(chmod 755 watermark.py, and you can run it as /path/to/watermark.py infile.pdf watermark.pdf outfile.pdf)
- You'll want to install
libpodofo-utils (or however it's called on your distro, but on debian, that's the name), and make sure you have the podofosign program.
Now, everything falls into place, in bash:
sign() { infile=$1 outfile=$2 podofosign -in "${infile}" -cert "yourcert.pem" -pkey "yourkey.pem" -out "${outfile}" } mark() { infile=$1 outfile=$2 /path/to/watermark "${infile}" "yourwatermark.pdf" "${outfile}" } mark_and_sign() { infile=$1 mark "${infile}" "${infile%.pdf}-marked.pdf" sign "${infile%.pdf}-marked.pdf" "${infile%.pdf}-signed.pdf" # optionally delete unsigned watermarked file: # rm "${infile%.pdf}-marked.pdf" } for file in *.pdf; do mark_and_sign "${file}" done
