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