texrender.py

import os
import tempfile
import subprocess
from django.conf import settings


class RenderError(subprocess.CalledProcessError):
    pass


def tex_to_pdf(source, jobname='django'):
    with tempfile.TemporaryDirectory() as d:
        base = os.path.join(d, jobname)
        with open(base + '.tex', 'w', encoding='utf8') as fp:
            fp.write(source)
        cmd = ('pdflatex', base + '.tex')
        p = subprocess.Popen(
            cmd,
            cwd=d,
            stdin=subprocess.DEVNULL,
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT)
        with p:
            output_bytes, _ = p.communicate()
        if p.returncode != 0:
            output = output_bytes.decode("utf8", errors="replace")
            raise RenderError(p.returncode, cmd, output, stderr=None)
        with open(base + '.pdf', 'rb') as fp:
            return fp.read()


def pdfnup(pdf, jobname='django'):
    with tempfile.TemporaryDirectory() as d:
        base = os.path.join(d, jobname)
        out = base + '-nup'
        with open(base + '.pdf', 'wb') as fp:
            fp.write(pdf)
        cmd = ('pdfnup', base + '.pdf', '-o', out + '.pdf')
        p = subprocess.Popen(
            cmd,
            cwd=d,
            stdin=subprocess.DEVNULL,
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT,
            universal_newlines=True)
        with p:
            output, _ = p.communicate()
        if p.returncode != 0:
            raise RenderError(p.returncode, cmd, output, stderr=None)
        with open(out + '.pdf', 'rb') as fp:
            return fp.read()


def run_lp(pdf, duplex=True, hostname=None, destination=None):
    if hostname is None:
        hostname = getattr(settings, 'CUPS_HOSTNAME', 'localhost')
    if destination is None:
        destination = settings.PRINT_DESTINATION
    with tempfile.NamedTemporaryFile(mode='wb', suffix='.pdf') as fp:
        fp.write(pdf)
        if duplex:
            opt = ('-o', 'Duplex=DuplexNoTumble')
        else:
            opt = ('-o', 'Duplex=None')

        cmd = ('lp', '-h', hostname, '-d', destination,) + opt + (fp.name,)
        p = subprocess.Popen(
            cmd,
            cwd=os.path.dirname(fp.name),
            stdin=subprocess.DEVNULL,
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT,
            universal_newlines=True)
        with p:
            output, _ = p.communicate()
        if p.returncode != 0:
            raise RenderError(p.returncode, cmd, output, stderr=None)
    return output


def print_new_document(fp, filename, username, **kwargs):
    '''Drop-in replacement for uniprint.api.print_new_document'''
    duplex = kwargs.pop('duplex', True)
    printer = kwargs.pop('printer')
    fake = kwargs.pop('fake', None)
    copies = kwargs.pop('copies', 1)
    if copies != 1:
        raise ValueError('can only print 1 copy at a time')
    if kwargs:
        raise TypeError('unsupported kwargs: %s' % kwargs)
    if not fake:
        run_lp(fp.read(), duplex=duplex)