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