apps/catalogue/views.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 tempfile
   6 import zipfile
   7 import sys
   8 import pprint
   9 import traceback
  10 import re
  11 import itertools
  12 from operator import itemgetter
  13
  14 from django.conf import settings
  15 from django.template import RequestContext
  16 from django.shortcuts import render_to_response, get_object_or_404
  17 from django.http import HttpResponse, HttpResponseRedirect, Http404
  18 from django.core.urlresolvers import reverse
  19 from django.db.models import Q
  20 from django.contrib.auth.decorators import login_required, user_passes_test
  21 from django.utils.datastructures import SortedDict
  22 from django.views.decorators.http import require_POST
  23 from django.contrib import auth
  24 from django.contrib.auth.forms import UserCreationForm, AuthenticationForm
  25 from django.utils import simplejson
  26 from django.utils.functional import Promise
  27 from django.utils.encoding import force_unicode
  28 from django.utils.http import urlquote_plus
  29 from django.views.decorators import cache
  30 from django.utils.translation import ugettext as _
  31 from django.views.generic.list_detail import object_list
  32
  33 from catalogue import models
  34 from catalogue import forms
  35 from catalogue.utils import split_tags
  36 from newtagging import views as newtagging_views
  37
  38
  39 staff_required = user_passes_test(lambda user: user.is_staff)
  40
  41
  42 class LazyEncoder(simplejson.JSONEncoder):
  43     def default(self, obj):
  44         if isinstance(obj, Promise):
  45             return force_unicode(obj)
  46         return obj
  47
  48
  49 def main_page(request):
  50     if request.user.is_authenticated():
  51         shelves = models.Tag.objects.filter(category='set', user=request.user)
  52         new_set_form = forms.NewSetForm()
  53
  54     tags = models.Tag.objects.exclude(category__in=('set', 'book'))
  55     for tag in tags:
  56         tag.count = tag.get_count()
  57     categories = split_tags(tags)
  58     fragment_tags = categories.get('theme', [])
  59
  60     form = forms.SearchForm()
  61     return render_to_response('catalogue/main_page.html', locals(),
  62         context_instance=RequestContext(request))
  63
  64
  65 def book_list(request):
  66     books = models.Book.objects.all()
  67     form = forms.SearchForm()
  68
  69     books_by_first_letter = SortedDict()
  70     for book in books:
  71         books_by_first_letter.setdefault(book.title[0], []).append(book)
  72
  73     return render_to_response('catalogue/book_list.html', locals(),
  74         context_instance=RequestContext(request))
  75
  76
  77 def differentiate_tags(request, tags, ambiguous_slugs):
  78     beginning = '/'.join(tag.url_chunk for tag in tags)
  79     unparsed = '/'.join(ambiguous_slugs[1:])
  80     options = []
  81     for tag in models.Tag.objects.exclude(category='book').filter(slug=ambiguous_slugs[0]):
  82         options.append({
  83             'url_args': '/'.join((beginning, tag.url_chunk, unparsed)).strip('/'),
  84             'tags': [tag]
  85         })
  86     return render_to_response('catalogue/differentiate_tags.html',
  87                 {'tags': tags, 'options': options, 'unparsed': ambiguous_slugs[1:]},
  88                 context_instance=RequestContext(request))
  89
  90
  91 def tagged_object_list(request, tags=''):
  92     try:
  93         tags = models.Tag.get_tag_list(tags)
  94     except models.Tag.DoesNotExist:
  95         raise Http404
  96     except models.Tag.MultipleObjectsReturned, e:
  97         return differentiate_tags(request, e.tags, e.ambiguous_slugs)
  98
  99     try:
 100         if len(tags) > settings.MAX_TAG_LIST:
 101             raise Http404
 102     except AttributeError:
 103         pass
 104
 105     if len([tag for tag in tags if tag.category == 'book']):
 106         raise Http404
 107
 108     theme_is_set = [tag for tag in tags if tag.category == 'theme']
 109     shelf_is_set = [tag for tag in tags if tag.category == 'set']
 110     only_shelf = shelf_is_set and len(tags) == 1
 111     only_my_shelf = only_shelf and request.user.is_authenticated() and request.user == tags[0].user
 112
 113     objects = only_author = pd_counter = None
 114     categories = {}
 115
 116     if theme_is_set:
 117         shelf_tags = [tag for tag in tags if tag.category == 'set']
 118         fragment_tags = [tag for tag in tags if tag.category != 'set']
 119         fragments = models.Fragment.tagged.with_all(fragment_tags)
 120
 121         if shelf_tags:
 122             books = models.Book.tagged.with_all(shelf_tags).order_by()
 123             l_tags = models.Tag.objects.filter(category='book', slug__in=[book.book_tag_slug() for book in books])
 124             fragments = models.Fragment.tagged.with_any(l_tags, fragments)
 125
 126         # newtagging goes crazy if we just try:
 127         #related_tags = models.Tag.objects.usage_for_queryset(fragments, counts=True,
 128         #                    extra={'where': ["catalogue_tag.category != 'book'"]})
 129         fragment_keys = [fragment.pk for fragment in fragments]
 130         if fragment_keys:
 131             related_tags = models.Fragment.tags.usage(counts=True,
 132                                 filters={'pk__in': fragment_keys},
 133                                 extra={'where': ["catalogue_tag.category != 'book'"]})
 134             related_tags = (tag for tag in related_tags if tag not in fragment_tags)
 135             categories = split_tags(related_tags)
 136
 137             objects = fragments
 138     else:
 139         # get relevant books and their tags
 140         objects = models.Book.tagged.with_all(tags).order_by()
 141         if not shelf_is_set:
 142             # eliminate descendants
 143             l_tags = models.Tag.objects.filter(category='book', slug__in=[book.book_tag_slug() for book in objects])
 144             descendants_keys = [book.pk for book in models.Book.tagged.with_any(l_tags)]
 145             if descendants_keys:
 146                 objects = objects.exclude(pk__in=descendants_keys)
 147
 148         # get related tags from `tag_counter` and `theme_counter`
 149         related_counts = {}
 150         tags_pks = [tag.pk for tag in tags]
 151         for book in objects:
 152             for tag_pk, value in itertools.chain(book.tag_counter.iteritems(), book.theme_counter.iteritems()):
 153                 if tag_pk in tags_pks:
 154                     continue
 155                 related_counts[tag_pk] = related_counts.get(tag_pk, 0) + value
 156         related_tags = models.Tag.objects.filter(pk__in=related_counts.keys())
 157         related_tags = [tag for tag in related_tags if tag not in tags]
 158         for tag in related_tags:
 159             tag.count = related_counts[tag.pk]
 160
 161         categories = split_tags(related_tags)
 162         del related_tags
 163
 164     if not objects:
 165         only_author = len(tags) == 1 and tags[0].category == 'author'
 166         pd_counter = only_author and tags[0].goes_to_pd()
 167         objects = models.Book.objects.none()
 168
 169     return object_list(
 170         request,
 171         objects,
 172         template_name='catalogue/tagged_object_list.html',
 173         extra_context={
 174             'categories': categories,
 175             'only_shelf': only_shelf,
 176             'only_author': only_author,
 177             'pd_counter': pd_counter,
 178             'only_my_shelf': only_my_shelf,
 179             'formats_form': forms.DownloadFormatsForm(),
 180
 181             'tags': tags,
 182         }
 183     )
 184
 185
 186 def book_fragments(request, book_slug, theme_slug):
 187     book = get_object_or_404(models.Book, slug=book_slug)
 188     book_tag = get_object_or_404(models.Tag, slug='l-' + book_slug, category='book')
 189     theme = get_object_or_404(models.Tag, slug=theme_slug, category='theme')
 190     fragments = models.Fragment.tagged.with_all([book_tag, theme])
 191
 192     form = forms.SearchForm()
 193     return render_to_response('catalogue/book_fragments.html', locals(),
 194         context_instance=RequestContext(request))
 195
 196
 197 def book_detail(request, slug):
 198     try:
 199         book = models.Book.objects.get(slug=slug)
 200     except models.Book.DoesNotExist:
 201         return book_stub_detail(request, slug)
 202
 203     book_tag = book.book_tag()
 204     tags = list(book.tags.filter(~Q(category='set')))
 205     categories = split_tags(tags)
 206     book_children = book.children.all().order_by('parent_number')
 207
 208     theme_counter = book.theme_counter
 209     book_themes = models.Tag.objects.filter(pk__in=theme_counter.keys())
 210     for tag in book_themes:
 211         tag.count = theme_counter[tag.pk]
 212
 213     extra_info = book.get_extra_info_value()
 214
 215     form = forms.SearchForm()
 216     return render_to_response('catalogue/book_detail.html', locals(),
 217         context_instance=RequestContext(request))
 218
 219
 220 def book_stub_detail(request, slug):
 221     book = get_object_or_404(models.BookStub, slug=slug)
 222     pd_counter = book.pd
 223     form = forms.SearchForm()
 224
 225     return render_to_response('catalogue/book_stub_detail.html', locals(),
 226         context_instance=RequestContext(request))
 227
 228
 229 def book_text(request, slug):
 230     book = get_object_or_404(models.Book, slug=slug)
 231     book_themes = {}
 232     for fragment in book.fragments.all():
 233         for theme in fragment.tags.filter(category='theme'):
 234             book_themes.setdefault(theme, []).append(fragment)
 235
 236     book_themes = book_themes.items()
 237     book_themes.sort(key=lambda s: s[0].sort_key)
 238     return render_to_response('catalogue/book_text.html', locals(),
 239         context_instance=RequestContext(request))
 240
 241
 242 # ==========
 243 # = Search =
 244 # ==========
 245
 246 def _no_diacritics_regexp(query):
 247     """ returns a regexp for searching for a query without diacritics
 248
 249     should be locale-aware """
 250     names = {
 251         u'a':u'aąĄ', u'c':u'cćĆ', u'e':u'eęĘ', u'l': u'lłŁ', u'n':u'nńŃ', u'o':u'oóÓ', u's':u'sśŚ', u'z':u'zźżŹŻ',
 252         u'ą':u'ąĄ', u'ć':u'ćĆ', u'ę':u'ęĘ', u'ł': u'łŁ', u'ń':u'ńŃ', u'ó':u'óÓ', u'ś':u'śŚ', u'ź':u'źŹ', u'ż':u'żŻ'
 253         }
 254     def repl(m):
 255         l = m.group()
 256         return u"(%s)" % '|'.join(names[l])
 257     return re.sub(u'[%s]' % (u''.join(names.keys())), repl, query)
 258
 259 def unicode_re_escape(query):
 260     """ Unicode-friendly version of re.escape """
 261     return re.sub('(?u)(\W)', r'\\\1', query)
 262
 263 def _word_starts_with(name, prefix):
 264     """returns a Q object getting models having `name` contain a word
 265     starting with `prefix`
 266
 267     We define word characters as alphanumeric and underscore, like in JS.
 268
 269     Works for MySQL, PostgreSQL, Oracle.
 270     For SQLite, _sqlite* version is substituted for this.
 271     """
 272     kwargs = {}
 273
 274     prefix = _no_diacritics_regexp(unicode_re_escape(prefix))
 275     # can't use [[:<:]] (word start),
 276     # but we want both `xy` and `(xy` to catch `(xyz)`
 277     kwargs['%s__iregex' % name] = u"(^|[^[:alnum:]_])%s" % prefix
 278
 279     return Q(**kwargs)
 280
 281
 282 def _sqlite_word_starts_with(name, prefix):
 283     """ version of _word_starts_with for SQLite
 284
 285     SQLite in Django uses Python re module
 286     """
 287     kwargs = {}
 288     prefix = _no_diacritics_regexp(unicode_re_escape(prefix))
 289     kwargs['%s__iregex' % name] = ur"(^|(?<=[^\wąćęłńóśźżĄĆĘŁŃÓŚŹŻ]))%s" % prefix
 290     return Q(**kwargs)
 291
 292
 293 if settings.DATABASE_ENGINE == 'sqlite3':
 294     _word_starts_with = _sqlite_word_starts_with
 295
 296
 297 def _tags_starting_with(prefix, user=None):
 298     prefix = prefix.lower()
 299     book_stubs = models.BookStub.objects.filter(_word_starts_with('title', prefix))
 300     books = models.Book.objects.filter(_word_starts_with('title', prefix))
 301     book_stubs = filter(lambda x: x not in books, book_stubs)
 302     tags = models.Tag.objects.filter(_word_starts_with('name', prefix))
 303     if user and user.is_authenticated():
 304         tags = tags.filter(~Q(category='book') & (~Q(category='set') | Q(user=user)))
 305     else:
 306         tags = tags.filter(~Q(category='book') & ~Q(category='set'))
 307     return list(books) + list(tags) + list(book_stubs)
 308
 309
 310 def _get_result_link(match, tag_list):
 311     if isinstance(match, models.Book) or isinstance(match, models.BookStub):
 312         return match.get_absolute_url()
 313     else:
 314         return reverse('catalogue.views.tagged_object_list',
 315             kwargs={'tags': '/'.join(tag.url_chunk for tag in tag_list + [match])}
 316         )
 317
 318 def _get_result_type(match):
 319     if isinstance(match, models.Book) or isinstance(match, models.BookStub):
 320         type = 'book'
 321     else:
 322         type = match.category
 323     return dict(models.TAG_CATEGORIES)[type]
 324
 325
 326
 327 def find_best_matches(query, user=None):
 328     """ Finds a Book, Tag or Bookstub best matching a query.
 329
 330     Returns a with:
 331       - zero elements when nothing is found,
 332       - one element when a best result is found,
 333       - more then one element on multiple exact matches
 334
 335     Raises a ValueError on too short a query.
 336     """
 337
 338     query = query.lower()
 339     if len(query) < 2:
 340         raise ValueError("query must have at least two characters")
 341
 342     result = tuple(_tags_starting_with(query, user))
 343     exact_matches = tuple(res for res in result if res.name.lower() == query)
 344     if exact_matches:
 345         return exact_matches
 346     else:
 347         return result[:1]
 348
 349
 350 def search(request):
 351     tags = request.GET.get('tags', '')
 352     prefix = request.GET.get('q', '')
 353
 354     try:
 355         tag_list = models.Tag.get_tag_list(tags)
 356     except:
 357         tag_list = []
 358
 359     try:
 360         result = find_best_matches(prefix, request.user)
 361     except ValueError:
 362         return render_to_response('catalogue/search_too_short.html', {'tags':tag_list, 'prefix':prefix},
 363             context_instance=RequestContext(request))
 364
 365     if len(result) == 1:
 366         return HttpResponseRedirect(_get_result_link(result[0], tag_list))
 367     elif len(result) > 1:
 368         return render_to_response('catalogue/search_multiple_hits.html',
 369             {'tags':tag_list, 'prefix':prefix, 'results':((x, _get_result_link(x, tag_list), _get_result_type(x)) for x in result)},
 370             context_instance=RequestContext(request))
 371     else:
 372         return render_to_response('catalogue/search_no_hits.html', {'tags':tag_list, 'prefix':prefix},
 373             context_instance=RequestContext(request))
 374
 375
 376 def tags_starting_with(request):
 377     prefix = request.GET.get('q', '')
 378     # Prefix must have at least 2 characters
 379     if len(prefix) < 2:
 380         return HttpResponse('')
 381     tags_list = []
 382     result = ""
 383     for tag in _tags_starting_with(prefix, request.user):
 384         if not tag.name in tags_list:
 385             result += "\n" + tag.name
 386             tags_list.append(tag.name)
 387     return HttpResponse(result)
 388
 389 # ====================
 390 # = Shelf management =
 391 # ====================
 392 @login_required
 393 @cache.never_cache
 394 def user_shelves(request):
 395     shelves = models.Tag.objects.filter(category='set', user=request.user)
 396     new_set_form = forms.NewSetForm()
 397     return render_to_response('catalogue/user_shelves.html', locals(),
 398             context_instance=RequestContext(request))
 399
 400 @cache.never_cache
 401 def book_sets(request, slug):
 402     book = get_object_or_404(models.Book, slug=slug)
 403     user_sets = models.Tag.objects.filter(category='set', user=request.user)
 404     book_sets = book.tags.filter(category='set', user=request.user)
 405
 406     if not request.user.is_authenticated():
 407         return HttpResponse(_('<p>To maintain your shelves you need to be logged in.</p>'))
 408
 409     if request.method == 'POST':
 410         form = forms.ObjectSetsForm(book, request.user, request.POST)
 411         if form.is_valid():
 412             old_shelves = list(book.tags.filter(category='set'))
 413             new_shelves = [models.Tag.objects.get(pk=id) for id in form.cleaned_data['set_ids']]
 414
 415             for shelf in [shelf for shelf in old_shelves if shelf not in new_shelves]:
 416                 shelf.book_count = None
 417                 shelf.save()
 418
 419             for shelf in [shelf for shelf in new_shelves if shelf not in old_shelves]:
 420                 shelf.book_count = None
 421                 shelf.save()
 422
 423             book.tags = new_shelves + list(book.tags.filter(~Q(category='set') | ~Q(user=request.user)))
 424             if request.is_ajax():
 425                 return HttpResponse(_('<p>Shelves were sucessfully saved.</p>'))
 426             else:
 427                 return HttpResponseRedirect('/')
 428     else:
 429         form = forms.ObjectSetsForm(book, request.user)
 430         new_set_form = forms.NewSetForm()
 431
 432     return render_to_response('catalogue/book_sets.html', locals(),
 433         context_instance=RequestContext(request))
 434
 435
 436 @login_required
 437 @require_POST
 438 @cache.never_cache
 439 def remove_from_shelf(request, shelf, book):
 440     book = get_object_or_404(models.Book, slug=book)
 441     shelf = get_object_or_404(models.Tag, slug=shelf, category='set', user=request.user)
 442
 443     if shelf in book.tags:
 444         models.Tag.objects.remove_tag(book, shelf)
 445
 446         shelf.book_count = None
 447         shelf.save()
 448
 449         return HttpResponse(_('Book was successfully removed from the shelf'))
 450     else:
 451         return HttpResponse(_('This book is not on the shelf'))
 452
 453
 454 def collect_books(books):
 455     """
 456     Returns all real books in collection.
 457     """
 458     result = []
 459     for book in books:
 460         if len(book.children.all()) == 0:
 461             result.append(book)
 462         else:
 463             result += collect_books(book.children.all())
 464     return result
 465
 466
 467 @cache.never_cache
 468 def download_shelf(request, slug):
 469     """"
 470     Create a ZIP archive on disk and transmit it in chunks of 8KB,
 471     without loading the whole file into memory. A similar approach can
 472     be used for large dynamic PDF files.
 473     """
 474     shelf = get_object_or_404(models.Tag, slug=slug, category='set')
 475
 476     formats = []
 477     form = forms.DownloadFormatsForm(request.GET)
 478     if form.is_valid():
 479         formats = form.cleaned_data['formats']
 480     if len(formats) == 0:
 481         formats = ['pdf', 'epub', 'odt', 'txt', 'mp3', 'ogg']
 482
 483     # Create a ZIP archive
 484     temp = tempfile.TemporaryFile()
 485     archive = zipfile.ZipFile(temp, 'w')
 486
 487     for book in collect_books(models.Book.tagged.with_all(shelf)):
 488         if 'pdf' in formats and book.pdf_file:
 489             filename = book.pdf_file.path
 490             archive.write(filename, str('%s.pdf' % book.slug))
 491         if 'epub' in formats and book.epub_file:
 492             filename = book.epub_file.path
 493             archive.write(filename, str('%s.epub' % book.slug))
 494         if 'odt' in formats and book.odt_file:
 495             filename = book.odt_file.path
 496             archive.write(filename, str('%s.odt' % book.slug))
 497         if 'txt' in formats and book.txt_file:
 498             filename = book.txt_file.path
 499             archive.write(filename, str('%s.txt' % book.slug))
 500         if 'mp3' in formats and book.mp3_file:
 501             filename = book.mp3_file.path
 502             archive.write(filename, str('%s.mp3' % book.slug))
 503         if 'ogg' in formats and book.ogg_file:
 504             filename = book.ogg_file.path
 505             archive.write(filename, str('%s.ogg' % book.slug))
 506     archive.close()
 507
 508     response = HttpResponse(content_type='application/zip', mimetype='application/x-zip-compressed')
 509     response['Content-Disposition'] = 'attachment; filename=%s.zip' % shelf.sort_key
 510     response['Content-Length'] = temp.tell()
 511
 512     temp.seek(0)
 513     response.write(temp.read())
 514     return response
 515
 516
 517 @cache.never_cache
 518 def shelf_book_formats(request, shelf):
 519     """"
 520     Returns a list of formats of books in shelf.
 521     """
 522     shelf = get_object_or_404(models.Tag, slug=shelf, category='set')
 523
 524     formats = {'pdf': False, 'epub': False, 'odt': False, 'txt': False, 'mp3': False, 'ogg': False}
 525
 526     for book in collect_books(models.Book.tagged.with_all(shelf)):
 527         if book.pdf_file:
 528             formats['pdf'] = True
 529         if book.epub_file:
 530             formats['epub'] = True
 531         if book.odt_file:
 532             formats['odt'] = True
 533         if book.txt_file:
 534             formats['txt'] = True
 535         if book.mp3_file:
 536             formats['mp3'] = True
 537         if book.ogg_file:
 538             formats['ogg'] = True
 539
 540     return HttpResponse(LazyEncoder().encode(formats))
 541
 542
 543 @login_required
 544 @require_POST
 545 @cache.never_cache
 546 def new_set(request):
 547     new_set_form = forms.NewSetForm(request.POST)
 548     if new_set_form.is_valid():
 549         new_set = new_set_form.save(request.user)
 550
 551         if request.is_ajax():
 552             return HttpResponse(_('<p>Shelf <strong>%s</strong> was successfully created</p>') % new_set)
 553         else:
 554             return HttpResponseRedirect('/')
 555
 556     return HttpResponseRedirect('/')
 557
 558
 559 @login_required
 560 @require_POST
 561 @cache.never_cache
 562 def delete_shelf(request, slug):
 563     user_set = get_object_or_404(models.Tag, slug=slug, category='set', user=request.user)
 564     user_set.delete()
 565
 566     if request.is_ajax():
 567         return HttpResponse(_('<p>Shelf <strong>%s</strong> was successfully removed</p>') % user_set.name)
 568     else:
 569         return HttpResponseRedirect('/')
 570
 571
 572 # ==================
 573 # = Authentication =
 574 # ==================
 575 @require_POST
 576 @cache.never_cache
 577 def login(request):
 578     form = AuthenticationForm(data=request.POST, prefix='login')
 579     if form.is_valid():
 580         auth.login(request, form.get_user())
 581         response_data = {'success': True, 'errors': {}}
 582     else:
 583         response_data = {'success': False, 'errors': form.errors}
 584     return HttpResponse(LazyEncoder(ensure_ascii=False).encode(response_data))
 585
 586
 587 @require_POST
 588 @cache.never_cache
 589 def register(request):
 590     registration_form = UserCreationForm(request.POST, prefix='registration')
 591     if registration_form.is_valid():
 592         user = registration_form.save()
 593         user = auth.authenticate(
 594             username=registration_form.cleaned_data['username'],
 595             password=registration_form.cleaned_data['password1']
 596         )
 597         auth.login(request, user)
 598         response_data = {'success': True, 'errors': {}}
 599     else:
 600         response_data = {'success': False, 'errors': registration_form.errors}
 601     return HttpResponse(LazyEncoder(ensure_ascii=False).encode(response_data))
 602
 603
 604 @cache.never_cache
 605 def logout_then_redirect(request):
 606     auth.logout(request)
 607     return HttpResponseRedirect(urlquote_plus(request.GET.get('next', '/'), safe='/?='))
 608
 609
 610
 611 # =========
 612 # = Admin =
 613 # =========
 614 @login_required
 615 @staff_required
 616 def import_book(request):
 617     """docstring for import_book"""
 618     book_import_form = forms.BookImportForm(request.POST, request.FILES)
 619     if book_import_form.is_valid():
 620         try:
 621             book_import_form.save()
 622         except:
 623             info = sys.exc_info()
 624             exception = pprint.pformat(info[1])
 625             tb = '\n'.join(traceback.format_tb(info[2]))
 626             return HttpResponse(_("An error occurred: %(exception)s\n\n%(tb)s") % {'exception':exception, 'tb':tb}, mimetype='text/plain')
 627         return HttpResponse(_("Book imported successfully"))
 628     else:
 629         return HttpResponse(_("Error importing file: %r") % book_import_form.errors)
 630
 631
 632
 633 def clock(request):
 634     """ Provides server time for jquery.countdown,
 635     in a format suitable for Date.parse()
 636     """
 637     from datetime import datetime
 638     return HttpResponse(datetime.now().strftime('%Y/%m/%d %H:%M:%S'))