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 from pdcounter import models as pdcounter_models
  38 from pdcounter import views as pdcounter_views
  39
  40
  41 staff_required = user_passes_test(lambda user: user.is_staff)
  42
  43
  44 class LazyEncoder(simplejson.JSONEncoder):
  45     def default(self, obj):
  46         if isinstance(obj, Promise):
  47             return force_unicode(obj)
  48         return obj
  49
  50 # shortcut for JSON reponses
  51 class JSONResponse(HttpResponse):
  52     def __init__(self, data={}, callback=None, **kwargs):
  53         # get rid of mimetype
  54         kwargs.pop('mimetype', None)
  55         data = simplejson.dumps(data)
  56         if callback:
  57             data = callback + "(" + data + ");"
  58         super(JSONResponse, self).__init__(data, mimetype="application/json", **kwargs)
  59
  60
  61 def main_page(request):
  62     if request.user.is_authenticated():
  63         shelves = models.Tag.objects.filter(category='set', user=request.user)
  64         new_set_form = forms.NewSetForm()
  65
  66     tags = models.Tag.objects.exclude(category__in=('set', 'book'))
  67     for tag in tags:
  68         tag.count = tag.get_count()
  69     categories = split_tags(tags)
  70     fragment_tags = categories.get('theme', [])
  71
  72     form = forms.SearchForm()
  73     return render_to_response('catalogue/main_page.html', locals(),
  74         context_instance=RequestContext(request))
  75
  76
  77 def book_list(request):
  78     form = forms.SearchForm()
  79
  80     books_by_parent = {}
  81     for book in models.Book.objects.all().order_by('parent_number'):
  82         books_by_parent.setdefault(book.parent, []).append(book)
  83
  84     orphans = []
  85     books_by_author = SortedDict()
  86     books_nav = SortedDict()
  87     for tag in models.Tag.objects.filter(category='author'):
  88         books_by_author[tag] = []
  89         if books_nav.has_key(tag.sort_key[0]):
  90             books_nav[tag.sort_key[0]].append(tag)
  91         else:
  92             books_nav[tag.sort_key[0]] = [tag]
  93
  94     for book in books_by_parent[None]:
  95         authors = list(book.tags.filter(category='author'))
  96         if authors:
  97             for author in authors:
  98                 books_by_author[author].append(book)
  99         else:
 100             orphans.append(book)
 101
 102     return render_to_response('catalogue/book_list.html', locals(),
 103         context_instance=RequestContext(request))
 104
 105
 106 def differentiate_tags(request, tags, ambiguous_slugs):
 107     beginning = '/'.join(tag.url_chunk for tag in tags)
 108     unparsed = '/'.join(ambiguous_slugs[1:])
 109     options = []
 110     for tag in models.Tag.objects.exclude(category='book').filter(slug=ambiguous_slugs[0]):
 111         options.append({
 112             'url_args': '/'.join((beginning, tag.url_chunk, unparsed)).strip('/'),
 113             'tags': [tag]
 114         })
 115     return render_to_response('catalogue/differentiate_tags.html',
 116                 {'tags': tags, 'options': options, 'unparsed': ambiguous_slugs[1:]},
 117                 context_instance=RequestContext(request))
 118
 119
 120 def tagged_object_list(request, tags=''):
 121     try:
 122         tags = models.Tag.get_tag_list(tags)
 123     except models.Tag.DoesNotExist:
 124         chunks = tags.split('/')
 125         if len(chunks) == 2 and chunks[0] == 'autor':
 126             return pdcounter_views.author_detail(request, chunks[1])
 127         else:
 128             raise Http404
 129     except models.Tag.MultipleObjectsReturned, e:
 130         return differentiate_tags(request, e.tags, e.ambiguous_slugs)
 131
 132     try:
 133         if len(tags) > settings.MAX_TAG_LIST:
 134             raise Http404
 135     except AttributeError:
 136         pass
 137
 138     if len([tag for tag in tags if tag.category == 'book']):
 139         raise Http404
 140
 141     theme_is_set = [tag for tag in tags if tag.category == 'theme']
 142     shelf_is_set = [tag for tag in tags if tag.category == 'set']
 143     only_shelf = shelf_is_set and len(tags) == 1
 144     only_my_shelf = only_shelf and request.user.is_authenticated() and request.user == tags[0].user
 145
 146     objects = only_author = None
 147     categories = {}
 148
 149     if theme_is_set:
 150         shelf_tags = [tag for tag in tags if tag.category == 'set']
 151         fragment_tags = [tag for tag in tags if tag.category != 'set']
 152         fragments = models.Fragment.tagged.with_all(fragment_tags)
 153
 154         if shelf_tags:
 155             books = models.Book.tagged.with_all(shelf_tags).order_by()
 156             l_tags = models.Tag.objects.filter(category='book', slug__in=[book.book_tag_slug() for book in books])
 157             fragments = models.Fragment.tagged.with_any(l_tags, fragments)
 158
 159         # newtagging goes crazy if we just try:
 160         #related_tags = models.Tag.objects.usage_for_queryset(fragments, counts=True,
 161         #                    extra={'where': ["catalogue_tag.category != 'book'"]})
 162         fragment_keys = [fragment.pk for fragment in fragments]
 163         if fragment_keys:
 164             related_tags = models.Fragment.tags.usage(counts=True,
 165                                 filters={'pk__in': fragment_keys},
 166                                 extra={'where': ["catalogue_tag.category != 'book'"]})
 167             related_tags = (tag for tag in related_tags if tag not in fragment_tags)
 168             categories = split_tags(related_tags)
 169
 170             objects = fragments
 171     else:
 172         # get relevant books and their tags
 173         objects = models.Book.tagged.with_all(tags)
 174         if not shelf_is_set:
 175             # eliminate descendants
 176             l_tags = models.Tag.objects.filter(category='book', slug__in=[book.book_tag_slug() for book in objects])
 177             descendants_keys = [book.pk for book in models.Book.tagged.with_any(l_tags)]
 178             if descendants_keys:
 179                 objects = objects.exclude(pk__in=descendants_keys)
 180
 181         # get related tags from `tag_counter` and `theme_counter`
 182         related_counts = {}
 183         tags_pks = [tag.pk for tag in tags]
 184         for book in objects:
 185             for tag_pk, value in itertools.chain(book.tag_counter.iteritems(), book.theme_counter.iteritems()):
 186                 if tag_pk in tags_pks:
 187                     continue
 188                 related_counts[tag_pk] = related_counts.get(tag_pk, 0) + value
 189         related_tags = models.Tag.objects.filter(pk__in=related_counts.keys())
 190         related_tags = [tag for tag in related_tags if tag not in tags]
 191         for tag in related_tags:
 192             tag.count = related_counts[tag.pk]
 193
 194         categories = split_tags(related_tags)
 195         del related_tags
 196
 197     if not objects:
 198         only_author = len(tags) == 1 and tags[0].category == 'author'
 199         objects = models.Book.objects.none()
 200
 201     return object_list(
 202         request,
 203         objects,
 204         template_name='catalogue/tagged_object_list.html',
 205         extra_context={
 206             'categories': categories,
 207             'only_shelf': only_shelf,
 208             'only_author': only_author,
 209             'only_my_shelf': only_my_shelf,
 210             'formats_form': forms.DownloadFormatsForm(),
 211
 212             'tags': tags,
 213         }
 214     )
 215
 216
 217 def book_fragments(request, book_slug, theme_slug):
 218     book = get_object_or_404(models.Book, slug=book_slug)
 219     book_tag = get_object_or_404(models.Tag, slug='l-' + book_slug, category='book')
 220     theme = get_object_or_404(models.Tag, slug=theme_slug, category='theme')
 221     fragments = models.Fragment.tagged.with_all([book_tag, theme])
 222
 223     form = forms.SearchForm()
 224     return render_to_response('catalogue/book_fragments.html', locals(),
 225         context_instance=RequestContext(request))
 226
 227
 228 def book_detail(request, slug):
 229     try:
 230         book = models.Book.objects.get(slug=slug)
 231     except models.Book.DoesNotExist:
 232         return pdcounter_views.book_stub_detail(request, slug)
 233
 234     book_tag = book.book_tag()
 235     tags = list(book.tags.filter(~Q(category='set')))
 236     categories = split_tags(tags)
 237     book_children = book.children.all().order_by('parent_number')
 238
 239     _book = book
 240     parents = []
 241     while _book.parent:
 242         parents.append(_book.parent)
 243         _book = _book.parent
 244     parents = reversed(parents)
 245
 246     theme_counter = book.theme_counter
 247     book_themes = models.Tag.objects.filter(pk__in=theme_counter.keys())
 248     for tag in book_themes:
 249         tag.count = theme_counter[tag.pk]
 250
 251     extra_info = book.get_extra_info_value()
 252
 253     form = forms.SearchForm()
 254     return render_to_response('catalogue/book_detail.html', locals(),
 255         context_instance=RequestContext(request))
 256
 257
 258 def book_text(request, slug):
 259     book = get_object_or_404(models.Book, slug=slug)
 260     if not book.has_html_file():
 261         raise Http404
 262     book_themes = {}
 263     for fragment in book.fragments.all():
 264         for theme in fragment.tags.filter(category='theme'):
 265             book_themes.setdefault(theme, []).append(fragment)
 266
 267     book_themes = book_themes.items()
 268     book_themes.sort(key=lambda s: s[0].sort_key)
 269     return render_to_response('catalogue/book_text.html', locals(),
 270         context_instance=RequestContext(request))
 271
 272
 273 # ==========
 274 # = Search =
 275 # ==========
 276
 277 def _no_diacritics_regexp(query):
 278     """ returns a regexp for searching for a query without diacritics
 279
 280     should be locale-aware """
 281     names = {
 282         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',
 283         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'
 284         }
 285     def repl(m):
 286         l = m.group()
 287         return u"(%s)" % '|'.join(names[l])
 288     return re.sub(u'[%s]' % (u''.join(names.keys())), repl, query)
 289
 290 def unicode_re_escape(query):
 291     """ Unicode-friendly version of re.escape """
 292     return re.sub('(?u)(\W)', r'\\\1', query)
 293
 294 def _word_starts_with(name, prefix):
 295     """returns a Q object getting models having `name` contain a word
 296     starting with `prefix`
 297
 298     We define word characters as alphanumeric and underscore, like in JS.
 299
 300     Works for MySQL, PostgreSQL, Oracle.
 301     For SQLite, _sqlite* version is substituted for this.
 302     """
 303     kwargs = {}
 304
 305     prefix = _no_diacritics_regexp(unicode_re_escape(prefix))
 306     # can't use [[:<:]] (word start),
 307     # but we want both `xy` and `(xy` to catch `(xyz)`
 308     kwargs['%s__iregex' % name] = u"(^|[^[:alnum:]_])%s" % prefix
 309
 310     return Q(**kwargs)
 311
 312
 313 def _sqlite_word_starts_with(name, prefix):
 314     """ version of _word_starts_with for SQLite
 315
 316     SQLite in Django uses Python re module
 317     """
 318     kwargs = {}
 319     prefix = _no_diacritics_regexp(unicode_re_escape(prefix))
 320     kwargs['%s__iregex' % name] = ur"(^|(?<=[^\wąćęłńóśźżĄĆĘŁŃÓŚŹŻ]))%s" % prefix
 321     return Q(**kwargs)
 322
 323
 324 if settings.DATABASES['default']['ENGINE'] == 'django.db.backends.sqlite3':
 325     _word_starts_with = _sqlite_word_starts_with
 326
 327
 328 def _tags_starting_with(prefix, user=None):
 329     prefix = prefix.lower()
 330     # PD counter
 331     book_stubs = pdcounter_models.BookStub.objects.filter(_word_starts_with('title', prefix))
 332     authors = pdcounter_models.Author.objects.filter(_word_starts_with('name', prefix))
 333
 334     books = models.Book.objects.filter(_word_starts_with('title', prefix))
 335     tags = models.Tag.objects.filter(_word_starts_with('name', prefix))
 336     if user and user.is_authenticated():
 337         tags = tags.filter(~Q(category='book') & (~Q(category='set') | Q(user=user)))
 338     else:
 339         tags = tags.filter(~Q(category='book') & ~Q(category='set'))
 340     return list(books) + list(tags) + list(book_stubs) + list(authors)
 341
 342
 343 def _get_result_link(match, tag_list):
 344     if isinstance(match, models.Tag):
 345         return reverse('catalogue.views.tagged_object_list',
 346             kwargs={'tags': '/'.join(tag.url_chunk for tag in tag_list + [match])}
 347         )
 348     else:
 349         return match.get_absolute_url()
 350
 351
 352 def _get_result_type(match):
 353     if isinstance(match, models.Book) or isinstance(match, pdcounter_models.BookStub):
 354         type = 'book'
 355     else:
 356         type = match.category
 357     return type
 358
 359
 360 def books_starting_with(prefix):
 361     prefix = prefix.lower()
 362     return models.Book.objects.filter(_word_starts_with('title', prefix))
 363
 364
 365 def find_best_matches(query, user=None):
 366     """ Finds a Book, Tag, BookStub or Author best matching a query.
 367
 368     Returns a with:
 369       - zero elements when nothing is found,
 370       - one element when a best result is found,
 371       - more then one element on multiple exact matches
 372
 373     Raises a ValueError on too short a query.
 374     """
 375
 376     query = query.lower()
 377     if len(query) < 2:
 378         raise ValueError("query must have at least two characters")
 379
 380     result = tuple(_tags_starting_with(query, user))
 381     # remove pdcounter stuff
 382     book_titles = set(match.pretty_title().lower() for match in result
 383                       if isinstance(match, models.Book))
 384     authors = set(match.name.lower() for match in result
 385                   if isinstance(match, models.Tag) and match.category=='author')
 386     result = tuple(res for res in result if not (
 387                  (isinstance(res, pdcounter_models.BookStub) and res.pretty_title().lower() in book_titles)
 388                  or (isinstance(res, pdcounter_models.Author) and res.name.lower() in authors)
 389              ))
 390
 391     exact_matches = tuple(res for res in result if res.name.lower() == query)
 392     if exact_matches:
 393         return exact_matches
 394     else:
 395         return tuple(result)[:1]
 396
 397
 398 def search(request):
 399     tags = request.GET.get('tags', '')
 400     prefix = request.GET.get('q', '')
 401
 402     try:
 403         tag_list = models.Tag.get_tag_list(tags)
 404     except:
 405         tag_list = []
 406
 407     try:
 408         result = find_best_matches(prefix, request.user)
 409     except ValueError:
 410         return render_to_response('catalogue/search_too_short.html', {'tags':tag_list, 'prefix':prefix},
 411             context_instance=RequestContext(request))
 412
 413     if len(result) == 1:
 414         return HttpResponseRedirect(_get_result_link(result[0], tag_list))
 415     elif len(result) > 1:
 416         return render_to_response('catalogue/search_multiple_hits.html',
 417             {'tags':tag_list, 'prefix':prefix, 'results':((x, _get_result_link(x, tag_list), _get_result_type(x)) for x in result)},
 418             context_instance=RequestContext(request))
 419     else:
 420         return render_to_response('catalogue/search_no_hits.html', {'tags':tag_list, 'prefix':prefix},
 421             context_instance=RequestContext(request))
 422
 423
 424 def tags_starting_with(request):
 425     prefix = request.GET.get('q', '')
 426     # Prefix must have at least 2 characters
 427     if len(prefix) < 2:
 428         return HttpResponse('')
 429     tags_list = []
 430     result = ""
 431     for tag in _tags_starting_with(prefix, request.user):
 432         if not tag.name in tags_list:
 433             result += "\n" + tag.name
 434             tags_list.append(tag.name)
 435     return HttpResponse(result)
 436
 437 def json_tags_starting_with(request, callback=None):
 438     # Callback for JSONP
 439     prefix = request.GET.get('q', '')
 440     callback = request.GET.get('callback', '')
 441     # Prefix must have at least 2 characters
 442     if len(prefix) < 2:
 443         return HttpResponse('')
 444     tags_list = []
 445     result = ""
 446     for tag in _tags_starting_with(prefix, request.user):
 447         if not tag.name in tags_list:
 448             result += "\n" + tag.name
 449             tags_list.append(tag.name)
 450     dict_result = {"matches": tags_list}
 451     return JSONResponse(dict_result, callback)
 452
 453 # ====================
 454 # = Shelf management =
 455 # ====================
 456 @login_required
 457 @cache.never_cache
 458 def user_shelves(request):
 459     shelves = models.Tag.objects.filter(category='set', user=request.user)
 460     new_set_form = forms.NewSetForm()
 461     return render_to_response('catalogue/user_shelves.html', locals(),
 462             context_instance=RequestContext(request))
 463
 464 @cache.never_cache
 465 def book_sets(request, slug):
 466     if not request.user.is_authenticated():
 467         return HttpResponse(_('<p>To maintain your shelves you need to be logged in.</p>'))
 468
 469     book = get_object_or_404(models.Book, slug=slug)
 470     user_sets = models.Tag.objects.filter(category='set', user=request.user)
 471     book_sets = book.tags.filter(category='set', user=request.user)
 472
 473     if request.method == 'POST':
 474         form = forms.ObjectSetsForm(book, request.user, request.POST)
 475         if form.is_valid():
 476             old_shelves = list(book.tags.filter(category='set'))
 477             new_shelves = [models.Tag.objects.get(pk=id) for id in form.cleaned_data['set_ids']]
 478
 479             for shelf in [shelf for shelf in old_shelves if shelf not in new_shelves]:
 480                 shelf.book_count = None
 481                 shelf.save()
 482
 483             for shelf in [shelf for shelf in new_shelves if shelf not in old_shelves]:
 484                 shelf.book_count = None
 485                 shelf.save()
 486
 487             book.tags = new_shelves + list(book.tags.filter(~Q(category='set') | ~Q(user=request.user)))
 488             if request.is_ajax():
 489                 return HttpResponse(_('<p>Shelves were sucessfully saved.</p>'))
 490             else:
 491                 return HttpResponseRedirect('/')
 492     else:
 493         form = forms.ObjectSetsForm(book, request.user)
 494         new_set_form = forms.NewSetForm()
 495
 496     return render_to_response('catalogue/book_sets.html', locals(),
 497         context_instance=RequestContext(request))
 498
 499
 500 @login_required
 501 @require_POST
 502 @cache.never_cache
 503 def remove_from_shelf(request, shelf, book):
 504     book = get_object_or_404(models.Book, slug=book)
 505     shelf = get_object_or_404(models.Tag, slug=shelf, category='set', user=request.user)
 506
 507     if shelf in book.tags:
 508         models.Tag.objects.remove_tag(book, shelf)
 509
 510         shelf.book_count = None
 511         shelf.save()
 512
 513         return HttpResponse(_('Book was successfully removed from the shelf'))
 514     else:
 515         return HttpResponse(_('This book is not on the shelf'))
 516
 517
 518 def collect_books(books):
 519     """
 520     Returns all real books in collection.
 521     """
 522     result = []
 523     for book in books:
 524         if len(book.children.all()) == 0:
 525             result.append(book)
 526         else:
 527             result += collect_books(book.children.all())
 528     return result
 529
 530
 531 @cache.never_cache
 532 def download_shelf(request, slug):
 533     """"
 534     Create a ZIP archive on disk and transmit it in chunks of 8KB,
 535     without loading the whole file into memory. A similar approach can
 536     be used for large dynamic PDF files.
 537     """
 538     shelf = get_object_or_404(models.Tag, slug=slug, category='set')
 539
 540     formats = []
 541     form = forms.DownloadFormatsForm(request.GET)
 542     if form.is_valid():
 543         formats = form.cleaned_data['formats']
 544     if len(formats) == 0:
 545         formats = ['pdf', 'epub', 'odt', 'txt', 'mp3', 'ogg', 'daisy']
 546
 547     # Create a ZIP archive
 548     temp = tempfile.TemporaryFile()
 549     archive = zipfile.ZipFile(temp, 'w')
 550
 551     already = set()
 552     for book in collect_books(models.Book.tagged.with_all(shelf)):
 553         if 'pdf' in formats and book.pdf_file:
 554             filename = book.pdf_file.path
 555             archive.write(filename, str('%s.pdf' % book.slug))
 556         if book.root_ancestor not in already and 'epub' in formats and book.root_ancestor.epub_file:
 557             filename = book.root_ancestor.epub_file.path
 558             archive.write(filename, str('%s.epub' % book.root_ancestor.slug))
 559             already.add(book.root_ancestor)
 560         if 'odt' in formats and book.odt_file:
 561             filename = book.odt_file.path
 562             archive.write(filename, str('%s.odt' % book.slug))
 563         if 'txt' in formats and book.txt_file:
 564             filename = book.txt_file.path
 565             archive.write(filename, str('%s.txt' % book.slug))
 566         if 'mp3' in formats and book.mp3_file:
 567             filename = book.mp3_file.path
 568             archive.write(filename, str('%s.mp3' % book.slug))
 569         if 'ogg' in formats and book.ogg_file:
 570             filename = book.ogg_file.path
 571             archive.write(filename, str('%s.ogg' % book.slug))
 572         if 'daisy' in formats and book.daisy_file:
 573             filename = book.daisy_file.path
 574             archive.write(filename, str('%s.daisy.zip' % book.slug))
 575     archive.close()
 576
 577     response = HttpResponse(content_type='application/zip', mimetype='application/x-zip-compressed')
 578     response['Content-Disposition'] = 'attachment; filename=%s.zip' % shelf.sort_key
 579     response['Content-Length'] = temp.tell()
 580
 581     temp.seek(0)
 582     response.write(temp.read())
 583     return response
 584
 585
 586 @cache.never_cache
 587 def shelf_book_formats(request, shelf):
 588     """"
 589     Returns a list of formats of books in shelf.
 590     """
 591     shelf = get_object_or_404(models.Tag, slug=shelf, category='set')
 592
 593     formats = {'pdf': False, 'epub': False, 'odt': False, 'txt': False, 'mp3': False, 'ogg': False, 'daisy': False}
 594
 595     for book in collect_books(models.Book.tagged.with_all(shelf)):
 596         if book.pdf_file:
 597             formats['pdf'] = True
 598         if book.root_ancestor.epub_file:
 599             formats['epub'] = True
 600         if book.odt_file:
 601             formats['odt'] = True
 602         if book.txt_file:
 603             formats['txt'] = True
 604         if book.mp3_file:
 605             formats['mp3'] = True
 606         if book.ogg_file:
 607             formats['ogg'] = True
 608         if book.daisy_file:
 609             formats['daisy'] = True
 610
 611     return HttpResponse(LazyEncoder().encode(formats))
 612
 613
 614 @login_required
 615 @require_POST
 616 @cache.never_cache
 617 def new_set(request):
 618     new_set_form = forms.NewSetForm(request.POST)
 619     if new_set_form.is_valid():
 620         new_set = new_set_form.save(request.user)
 621
 622         if request.is_ajax():
 623             return HttpResponse(_('<p>Shelf <strong>%s</strong> was successfully created</p>') % new_set)
 624         else:
 625             return HttpResponseRedirect('/')
 626
 627     return HttpResponseRedirect('/')
 628
 629
 630 @login_required
 631 @require_POST
 632 @cache.never_cache
 633 def delete_shelf(request, slug):
 634     user_set = get_object_or_404(models.Tag, slug=slug, category='set', user=request.user)
 635     user_set.delete()
 636
 637     if request.is_ajax():
 638         return HttpResponse(_('<p>Shelf <strong>%s</strong> was successfully removed</p>') % user_set.name)
 639     else:
 640         return HttpResponseRedirect('/')
 641
 642
 643 # ==================
 644 # = Authentication =
 645 # ==================
 646 @require_POST
 647 @cache.never_cache
 648 def login(request):
 649     form = AuthenticationForm(data=request.POST, prefix='login')
 650     if form.is_valid():
 651         auth.login(request, form.get_user())
 652         response_data = {'success': True, 'errors': {}}
 653     else:
 654         response_data = {'success': False, 'errors': form.errors}
 655     return HttpResponse(LazyEncoder(ensure_ascii=False).encode(response_data))
 656
 657
 658 @require_POST
 659 @cache.never_cache
 660 def register(request):
 661     registration_form = UserCreationForm(request.POST, prefix='registration')
 662     if registration_form.is_valid():
 663         user = registration_form.save()
 664         user = auth.authenticate(
 665             username=registration_form.cleaned_data['username'],
 666             password=registration_form.cleaned_data['password1']
 667         )
 668         auth.login(request, user)
 669         response_data = {'success': True, 'errors': {}}
 670     else:
 671         response_data = {'success': False, 'errors': registration_form.errors}
 672     return HttpResponse(LazyEncoder(ensure_ascii=False).encode(response_data))
 673
 674
 675 @cache.never_cache
 676 def logout_then_redirect(request):
 677     auth.logout(request)
 678     return HttpResponseRedirect(urlquote_plus(request.GET.get('next', '/'), safe='/?='))
 679
 680
 681
 682 # =========
 683 # = Admin =
 684 # =========
 685 @login_required
 686 @staff_required
 687 def import_book(request):
 688     """docstring for import_book"""
 689     book_import_form = forms.BookImportForm(request.POST, request.FILES)
 690     if book_import_form.is_valid():
 691         try:
 692             book_import_form.save()
 693         except:
 694             info = sys.exc_info()
 695             exception = pprint.pformat(info[1])
 696             tb = '\n'.join(traceback.format_tb(info[2]))
 697             return HttpResponse(_("An error occurred: %(exception)s\n\n%(tb)s") % {'exception':exception, 'tb':tb}, mimetype='text/plain')
 698         return HttpResponse(_("Book imported successfully"))
 699     else:
 700         return HttpResponse(_("Error importing file: %r") % book_import_form.errors)
 701
 702
 703
 704 def clock(request):
 705     """ Provides server time for jquery.countdown,
 706     in a format suitable for Date.parse()
 707     """
 708     from datetime import datetime
 709     return HttpResponse(datetime.now().strftime('%Y/%m/%d %H:%M:%S'))