Returning a PDF response in Django

Question

I'm asking a very similar question to this one. I'm creating a pdf using wkhtmltopdf on an Ubuntu server in Django.

from tempfile import *
from subprocess import Popen, PIPE

tempfile = gettempdir()+"/results.pdf"
papersize = 'Tabloid'
orientation = 'Landscape'
command_args = "wkhtmltopdf -O %s -s %s -T 0 -R 0 -B 0 -L 0 http://pdfurl %s" %(orientation, papersize, tempfile)
popen = Popen(command_args, stdout=PIPE, stderr=PIPE)
pdf_contents = popen.stdout().read()
popen.terminate()
popen.wait()
response = HttpResponse(pdf_contents, mimetype='application/pdf')
return response

This gives me a "no such file or directory" error on the popen = Popen... line. So I changed that line to

popen = Popen(["sh", "-c", command_args], stdout=PIPE, stderr=PIPE)

and now I get a "'file' object is not callable" error on the pdf_contents =... line.

I've also tried adding .communicate() to the popen =... line but I can't seem to locate the pdf output that way. I should add that typing the command_args line into the command line creates a pdf just fine. Can anyone point me in the right direction?