apps/reporting/utils.py

   1 # -*- coding: utf-8 -*-
   2 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
   3 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
   4 #
   5 from errno import ENOENT
   6 import os
   7 import os.path
   8 from django.conf import settings
   9 import logging
  10 from django.http import HttpResponse
  11
  12 logger = logging.getLogger(__name__)
  13
  14
  15 def render_to_pdf(output_path, template, context=None, add_files=None):
  16     """Renders a TeXML document into a PDF file.
  17
  18     :param str output_path: is where the PDF file should go
  19     :param str template: is a TeXML template path
  20     :param context: is context for rendering the template
  21     :param dict add_files: a dictionary of additional files XeTeX will need
  22     """
  23
  24     from StringIO import StringIO
  25     import shutil
  26     from tempfile import mkdtemp
  27     import subprocess
  28     import Texml.processor
  29     from django.template.loader import render_to_string
  30
  31     rendered = render_to_string(template, context)
  32     texml = StringIO(rendered.encode('utf-8'))
  33     tempdir = mkdtemp(prefix = "render_to_pdf-")
  34     tex_path = os.path.join(tempdir, "doc.tex")
  35     with open(tex_path, 'w') as tex_file:
  36         Texml.processor.process(texml, tex_file, encoding="utf-8")
  37
  38     if add_files:
  39         for add_name, src_file in add_files.items():
  40             add_path = os.path.join(tempdir, add_name)
  41             if hasattr(src_file, "read"):
  42                 with open(add_path, 'w') as add_file:
  43                     add_file.write(add_file.read())
  44             else:
  45                 shutil.copy(src_file, add_path)
  46
  47     cwd = os.getcwd()
  48     os.chdir(tempdir)
  49     try:
  50         subprocess.check_call(['xelatex', '-interaction=batchmode', tex_path],
  51             stdout=subprocess.PIPE, stderr=subprocess.PIPE)
  52         try:
  53             os.makedirs(os.path.dirname(output_path))
  54         except:
  55             pass
  56         shutil.move(os.path.join(tempdir, "doc.pdf"), output_path)
  57     finally:
  58         os.chdir(cwd)
  59         shutil.rmtree(tempdir)
  60
  61
  62 def read_chunks(f, size=8192):
  63     chunk = f.read(size)
  64     while chunk:
  65         yield chunk
  66         chunk = f.read(size)
  67
  68
  69 def generated_file_view(file_name, mime_type, send_name=None, signals=None):
  70     file_path = os.path.join(settings.MEDIA_ROOT, file_name)
  71     file_url = os.path.join(settings.MEDIA_URL, file_name)
  72     if send_name is None:
  73         send_name = os.path.basename(file_name)
  74
  75     def signal_handler(*args, **kwargs):
  76         try:
  77             os.unlink(file_path)
  78         except OSError as oe:
  79             if oe.errno != ENOENT:
  80                 raise oe
  81
  82     if signals:
  83         for signal in signals:
  84             signal.connect(signal_handler, weak=False)
  85
  86     def decorator(func):
  87         def view(request, *args, **kwargs):
  88             if not os.path.exists(file_path):
  89                 func(file_path, *args, **kwargs)
  90
  91             if hasattr(send_name, "__call__"):
  92                 name = send_name()
  93             else:
  94                 name = send_name
  95
  96             response = HttpResponse(mimetype=mime_type)
  97             response['Content-Disposition'] = 'attachment; filename=%s' % name
  98             with open(file_path) as f:
  99                 for chunk in read_chunks(f):
 100                     response.write(chunk)
 101             return response
 102         return view
 103     return decorator