Fixed admin template bug: load before extends.

[wolnelektury.git] / apps / catalogue / views.py

diff --git a/apps/catalogue/views.py b/apps/catalogue/views.py
index 3b9f31d..6de5a26 100644 (file)
--- a/apps/catalogue/views.py
+++ b/apps/catalogue/views.py
@@ -1,10 +1,20 @@
 # -*- coding: utf-8 -*-
 # -*- coding: utf-8 -*-

+# This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
+# Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
+#
+import tempfile
+import zipfile
+import sys
+import pprint
+import traceback
+
+from django.conf import settings

 from django.template import RequestContext
 from django.shortcuts import render_to_response, get_object_or_404
 from django.http import HttpResponse, HttpResponseRedirect, Http404
 from django.core.urlresolvers import reverse
 from django.db.models import Q
 from django.template import RequestContext
 from django.shortcuts import render_to_response, get_object_or_404
 from django.http import HttpResponse, HttpResponseRedirect, Http404
 from django.core.urlresolvers import reverse
 from django.db.models import Q

-from django.contrib.auth.decorators import login_required
+from django.contrib.auth.decorators import login_required, user_passes_test

 from django.utils.datastructures import SortedDict
 from django.views.decorators.http import require_POST
 from django.contrib import auth
 from django.utils.datastructures import SortedDict
 from django.views.decorators.http import require_POST
 from django.contrib import auth


@@ -12,6 +22,7 @@ from django.contrib.auth.forms import UserCreationForm, AuthenticationForm
 from django.utils import simplejson
 from django.utils.functional import Promise
 from django.utils.encoding import force_unicode
 from django.utils import simplejson
 from django.utils.functional import Promise
 from django.utils.encoding import force_unicode

+from django.views.decorators import cache

 
 from catalogue import models
 from catalogue import forms
 
 from catalogue import models
 from catalogue import forms


@@ -19,6 +30,9 @@ from catalogue.utils import split_tags
 from newtagging import views as newtagging_views
 
 
 from newtagging import views as newtagging_views
 
 

+staff_required = user_passes_test(lambda user: user.is_staff)
+
+

 class LazyEncoder(simplejson.JSONEncoder):
     def default(self, obj):
         if isinstance(obj, Promise):
 class LazyEncoder(simplejson.JSONEncoder):
     def default(self, obj):
         if isinstance(obj, Promise):


@@ -26,63 +40,17 @@ class LazyEncoder(simplejson.JSONEncoder):
         return obj
 
 
         return obj
 
 

-def search(request):
-    query = request.GET.get('q', '')
-    tags = request.GET.get('tags', '')
-    if tags == '':
-        tags = []
-    
-    try:
-        tag_list = models.Tag.get_tag_list(tags)
-        tag = models.Tag.objects.get(name=query)
-    except models.Tag.DoesNotExist:
-        try:
-            book = models.Book.objects.get(title=query)
-            return HttpResponseRedirect(book.get_absolute_url())
-        except models.Book.DoesNotExist:
-            return HttpResponseRedirect(reverse('catalogue.views.main_page'))
-    else:
-        tag_list.append(tag)
-        return HttpResponseRedirect(reverse('catalogue.views.tagged_object_list', 
-            kwargs={'tags': '/'.join(tag.slug for tag in tag_list)}
-        ))
-
-
-def tags_starting_with(request):
-    try:
-        prefix = request.GET['q']
-        if len(prefix) < 2:
-            raise KeyError
-            
-        books = models.Book.objects.filter(title__icontains=prefix)
-        tags = models.Tag.objects.filter(name__icontains=prefix)
-        if request.user.is_authenticated():
-            tags = tags.filter(~Q(category='set') | Q(user=request.user))
-        else:
-            tags = tags.filter(~Q(category='set'))
-        
-        completions = [book.title for book in books] + [tag.name for tag in tags]
-
-        return HttpResponse('\n'.join(completions))    
-    
-    except KeyError:
-        return HttpResponse('')
-
-

 def main_page(request):    
     if request.user.is_authenticated():
         shelves = models.Tag.objects.filter(category='set', user=request.user)
         new_set_form = forms.NewSetForm()
 def main_page(request):    
     if request.user.is_authenticated():
         shelves = models.Tag.objects.filter(category='set', user=request.user)
         new_set_form = forms.NewSetForm()

-        extra_where = '((NOT catalogue_tag.category = "set" AND catalogue_tag.main_page = 1) OR catalogue_tag.user_id = %d)' % request.user.id
-    else:
-        extra_where = 'NOT catalogue_tag.category = "set" AND catalogue_tag.main_page = 1'
+    extra_where = "NOT catalogue_tag.category = 'set'"

     tags = models.Tag.objects.usage_for_model(models.Book, counts=True, extra={'where': [extra_where]})
     fragment_tags = models.Tag.objects.usage_for_model(models.Fragment, counts=True,
     tags = models.Tag.objects.usage_for_model(models.Book, counts=True, extra={'where': [extra_where]})
     fragment_tags = models.Tag.objects.usage_for_model(models.Fragment, counts=True,

-        extra={'where': ['catalogue_tag.category = "theme"'] + [extra_where]})
+        extra={'where': ["catalogue_tag.category = 'theme'"] + [extra_where]})

     categories = split_tags(tags)
     
     form = forms.SearchForm()
     categories = split_tags(tags)
     
     form = forms.SearchForm()

-    

     return render_to_response('catalogue/main_page.html', locals(),
         context_instance=RequestContext(request))
 
     return render_to_response('catalogue/main_page.html', locals(),
         context_instance=RequestContext(request))
 


@@ -100,75 +68,190 @@ def book_list(request):
 
 
 def tagged_object_list(request, tags=''):
 
 
 def tagged_object_list(request, tags=''):

+    # Prevent DoS attacks on our database
+    if len(tags.split('/')) > 6:
+        raise Http404
+        

     try:
         tags = models.Tag.get_tag_list(tags)
     except models.Tag.DoesNotExist:
         raise Http404
     
     try:
         tags = models.Tag.get_tag_list(tags)
     except models.Tag.DoesNotExist:
         raise Http404
     

+    if len([tag for tag in tags if tag.category == 'book']):
+        raise Http404
+    

     model = models.Book
     model = models.Book

-    theme_is_set = any(tag.category == 'theme' for tag in tags)
+    shelf = [tag for tag in tags if tag.category == 'set']
+    shelf_is_set = (len(tags) == 1 and tags[0].category == 'set')
+    theme_is_set = len([tag for tag in tags if tag.category == 'theme']) > 0

     if theme_is_set:
         model = models.Fragment
     if theme_is_set:
         model = models.Fragment

+    only_author = len(tags) == 1 and tags[0].category == 'author'
+    pd_counter = only_author and tags[0].goes_to_pd()
+
+    user_is_owner = (len(shelf) and request.user.is_authenticated() and request.user == shelf[0].user)

     
     

-    if request.user.is_authenticated():
-        extra_where = '(NOT catalogue_tag.category = "set" OR catalogue_tag.user_id = %d)' % request.user.id
-    else:
-        extra_where = 'NOT catalogue_tag.category = "set"'
+    extra_where = "catalogue_tag.category NOT IN ('set', 'book')"

     related_tags = models.Tag.objects.related_for_model(tags, model, counts=True, extra={'where': [extra_where]})
     categories = split_tags(related_tags)
 
     related_tags = models.Tag.objects.related_for_model(tags, model, counts=True, extra={'where': [extra_where]})
     categories = split_tags(related_tags)
 

+    if not (theme_is_set or shelf_is_set):
+        model=models.Book.objects.filter(parent=None)
+    

     return newtagging_views.tagged_object_list(
         request,
         tag_model=models.Tag,
         queryset_or_model=model,
         tags=tags,
         template_name='catalogue/tagged_object_list.html',
     return newtagging_views.tagged_object_list(
         request,
         tag_model=models.Tag,
         queryset_or_model=model,
         tags=tags,
         template_name='catalogue/tagged_object_list.html',

-        extra_context = {'categories': categories },
+        extra_context = {
+            'categories': categories,
+            'shelf_is_set': shelf_is_set,
+            'only_author': only_author,
+            'pd_counter': pd_counter,
+            'user_is_owner': user_is_owner,
+            'formats_form': forms.DownloadFormatsForm(),
+        },

     )
 
 
     )
 
 

+def book_fragments(request, book_slug, theme_slug):
+    book = get_object_or_404(models.Book, slug=book_slug)
+    book_tag = get_object_or_404(models.Tag, slug='l-' + book_slug)
+    theme = get_object_or_404(models.Tag, slug=theme_slug)
+    fragments = models.Fragment.tagged.with_all([book_tag, theme])
+    
+    form = forms.SearchForm()
+    return render_to_response('catalogue/book_fragments.html', locals(),
+        context_instance=RequestContext(request))
+
+

 def book_detail(request, slug):
 def book_detail(request, slug):

-    book = get_object_or_404(models.Book, slug=slug)
+    try:
+        book = models.Book.objects.get(slug=slug)
+    except models.Book.DoesNotExist:
+        return book_stub_detail(request, slug)
+
+    book_tag = get_object_or_404(models.Tag, slug = 'l-' + slug)

     tags = list(book.tags.filter(~Q(category='set')))
     categories = split_tags(tags)
     tags = list(book.tags.filter(~Q(category='set')))
     categories = split_tags(tags)

+    book_children = book.children.all().order_by('parent_number')
+    extra_where = "catalogue_tag.category = 'theme'"
+    book_themes = models.Tag.objects.related_for_model(book_tag, models.Fragment, counts=True, extra={'where': [extra_where]})
+    extra_info = book.get_extra_info_value()

     
     form = forms.SearchForm()
     return render_to_response('catalogue/book_detail.html', locals(),
         context_instance=RequestContext(request))
 
 
     
     form = forms.SearchForm()
     return render_to_response('catalogue/book_detail.html', locals(),
         context_instance=RequestContext(request))
 
 

-def logout_then_redirect(request):
-    auth.logout(request)
-    return HttpResponseRedirect(request.GET.get('next', '/'))
+def book_stub_detail(request, slug):
+    book = get_object_or_404(models.BookStub, slug=slug)
+    pd_counter = book.pd
+    form = forms.SearchForm()
+    
+    return render_to_response('catalogue/book_stub_detail.html', locals(),
+        context_instance=RequestContext(request))
+    

 
 

+def book_text(request, slug):
+    book = get_object_or_404(models.Book, slug=slug)
+    book_themes = {}
+    for fragment in book.fragments.all():
+        for theme in fragment.tags.filter(category='theme'):
+            book_themes.setdefault(theme, []).append(fragment)
+    
+    book_themes = book_themes.items()
+    book_themes.sort(key=lambda s: s[0].sort_key)
+    return render_to_response('catalogue/book_text.html', locals(),
+        context_instance=RequestContext(request))

 
 

-@require_POST
-def register(request):
-    registration_form = UserCreationForm(request.POST, prefix='registration')
-    if registration_form.is_valid():
-        user = registration_form.save()
-        user = auth.authenticate(
-            username=registration_form.cleaned_data['username'], 
-            password=registration_form.cleaned_data['password1']
-        )
-        auth.login(request, user)
-        response_data = {'success': True, 'errors': {}}
+
+# ==========
+# = Search =
+# ==========
+def _word_starts_with(name, prefix):
+    """returns a Q object gettings models having `name` contain a word
+    starting with `prefix`
+    """
+    kwargs = {}
+    if settings.DATABASE_ENGINE in ('mysql', 'postgresql_psycopg2', 'postgresql'):
+        # we must escape `prefix` so that it only matches literally
+        for special in r'\^$.*+?|(){}[]':
+            prefix = prefix.replace(special, '\\' + special)
+        
+        # we could use a [[:<:]] (word start), 
+        # but we want both `xy` and `(xy` to catch `(xyz)`
+        kwargs['%s__iregex' % name] = u"(^|[^[:alpha:]])%s" % prefix

     else:
     else:

-        response_data = {'success': False, 'errors': registration_form.errors}
-    return HttpResponse(LazyEncoder(ensure_ascii=False).encode(response_data))
+        # don't know how to do a generic regex
+        # checking for simple icontain instead
+        kwargs['%s__icontains' % name] = prefix
+    return Q(**kwargs)
+
+
+def _tags_starting_with(prefix, user):
+    book_stubs = models.BookStub.objects.filter(_word_starts_with('title', prefix))
+    books = models.Book.objects.filter(_word_starts_with('title', prefix))
+    book_stubs = filter(lambda x: x not in books, book_stubs)
+    tags = models.Tag.objects.filter(_word_starts_with('name', prefix))
+    if user.is_authenticated():
+        tags = tags.filter(~Q(category='book') & (~Q(category='set') | Q(user=user)))
+    else:
+        tags = tags.filter(~Q(category='book') & ~Q(category='set'))

 
 

+    return list(books) + list(tags) + list(book_stubs)
+        

 
 

-@require_POST
-def login(request):
-    form = AuthenticationForm(data=request.POST, prefix='login')
-    if form.is_valid():
-        auth.login(request, form.get_user())
-        response_data = {'success': True, 'errors': {}}
+def search(request):
+    tags = request.GET.get('tags', '')
+    prefix = request.GET.get('q', '')
+    # Prefix must have at least 2 characters
+    if len(prefix) < 2:
+        return HttpResponse('')
+    
+    try:
+        tag_list = models.Tag.get_tag_list(tags)
+    except:
+        tag_list = []
+    
+    result = _tags_starting_with(prefix, request.user)
+    if len(result) > 0:
+        tag = result[0]
+        if isinstance(tag, models.Book) or isinstance(tag, models.BookStub):
+            return HttpResponseRedirect(tag.get_absolute_url())
+        else:
+            tag_list.append(tag)
+            
+            return HttpResponseRedirect(reverse('catalogue.views.tagged_object_list', 
+                kwargs={'tags': '/'.join(tag.slug for tag in tag_list)}
+            ))

     else:
     else:

-        response_data = {'success': False, 'errors': form.errors}
-    return HttpResponse(LazyEncoder(ensure_ascii=False).encode(response_data))
+        return render_to_response('catalogue/search_no_hits.html', {'query':prefix, 'tags':tag_list},
+            context_instance=RequestContext(request))
+
+
+def tags_starting_with(request):
+    prefix = request.GET.get('q', '')
+    # Prefix must have at least 2 characters
+    if len(prefix) < 2:
+        return HttpResponse('')
+    
+    return HttpResponse('\n'.join(tag.name for tag in _tags_starting_with(prefix, request.user)))
+

 
 

+# ====================
+# = Shelf management =
+# ====================
+@login_required
+@cache.never_cache
+def user_shelves(request):
+    shelves = models.Tag.objects.filter(category='set', user=request.user)
+    new_set_form = forms.NewSetForm()
+    return render_to_response('catalogue/user_shelves.html', locals(),
+            context_instance=RequestContext(request))

 
 

+@cache.never_cache

 def book_sets(request, slug):
     book = get_object_or_404(models.Book, slug=slug)
     user_sets = models.Tag.objects.filter(category='set', user=request.user)
 def book_sets(request, slug):
     book = get_object_or_404(models.Book, slug=slug)
     user_sets = models.Tag.objects.filter(category='set', user=request.user)


@@ -180,8 +263,18 @@ def book_sets(request, slug):
     if request.method == 'POST':
         form = forms.ObjectSetsForm(book, request.user, request.POST)
         if form.is_valid():
     if request.method == 'POST':
         form = forms.ObjectSetsForm(book, request.user, request.POST)
         if form.is_valid():

-            book.tags = ([models.Tag.objects.get(pk=id) for id in form.cleaned_data['set_ids']] +
-                list(book.tags.filter(~Q(category='set') | ~Q(user=request.user))))
+            old_shelves = list(book.tags.filter(category='set'))
+            new_shelves = [models.Tag.objects.get(pk=id) for id in form.cleaned_data['set_ids']]
+            
+            for shelf in [shelf for shelf in old_shelves if shelf not in new_shelves]:
+                shelf.book_count -= 1
+                shelf.save()
+                
+            for shelf in [shelf for shelf in new_shelves if shelf not in old_shelves]:
+                shelf.book_count += 1
+                shelf.save()
+            
+            book.tags = new_shelves + list(book.tags.filter(~Q(category='set') | ~Q(user=request.user)))

             if request.is_ajax():
                 return HttpResponse('<p>Półki zostały zapisane.</p>')
             else:
             if request.is_ajax():
                 return HttpResponse('<p>Półki zostały zapisane.</p>')
             else:


@@ -194,63 +287,198 @@ def book_sets(request, slug):
         context_instance=RequestContext(request))
 
 
         context_instance=RequestContext(request))
 
 

-def fragment_sets(request, id):
-    fragment = get_object_or_404(models.Fragment, pk=id)
-    user_sets = models.Tag.objects.filter(category='set', user=request.user)
-    fragment_sets = fragment.tags.filter(category='set', user=request.user)
+@login_required
+@require_POST
+@cache.never_cache
+def remove_from_shelf(request, shelf, book):
+    book = get_object_or_404(models.Book, slug=book)
+    shelf = get_object_or_404(models.Tag, slug=shelf, category='set', user=request.user)
+    
+    models.Tag.objects.remove_tag(book, shelf)
+    
+    shelf.book_count -= 1
+    shelf.save()
+    
+    return HttpResponse('Usunieto')

 
 

-    if not request.user.is_authenticated():
-        return HttpResponse('<p>Aby zarządzać swoimi półkami, musisz się zalogować.</p>')

 
 

-    if request.method == 'POST':
-        form = forms.ObjectSetsForm(fragment, request.user, request.POST)
-        if form.is_valid():
-            fragment.tags = ([models.Tag.objects.get(pk=id) for id in form.cleaned_data['set_ids']] +
-                list(fragment.tags.filter(~Q(category='set') | ~Q(user=request.user))))
-            if request.is_ajax():
-                return HttpResponse('<p>Półki zostały zapisane.</p>')
-            else:
-                return HttpResponseRedirect('/')
-    else:
-        form = forms.ObjectSetsForm(fragment, request.user)
-        new_set_form = forms.NewSetForm()
+def collect_books(books):
+    """
+    Returns all real books in collection.
+    """
+    result = []
+    for book in books:
+        if len(book.children.all()) == 0:
+            result.append(book)
+        else:
+            result += collect_books(book.children.all())
+    return result
+
+
+@cache.never_cache
+def download_shelf(request, slug):
+    """"
+    Create a ZIP archive on disk and transmit it in chunks of 8KB,
+    without loading the whole file into memory. A similar approach can
+    be used for large dynamic PDF files.                                        
+    """
+    shelf = get_object_or_404(models.Tag, slug=slug, category='set')
+    
+    formats = []
+    form = forms.DownloadFormatsForm(request.GET)
+    if form.is_valid():
+        formats = form.cleaned_data['formats']
+    if len(formats) == 0:
+        formats = ['pdf', 'odt', 'txt', 'mp3', 'ogg']
+    
+    # Create a ZIP archive
+    temp = temp = tempfile.TemporaryFile()
+    archive = zipfile.ZipFile(temp, 'w')
+    
+    for book in collect_books(models.Book.tagged.with_all(shelf)):
+        if 'pdf' in formats and book.pdf_file:
+            filename = book.pdf_file.path
+            archive.write(filename, str('%s.pdf' % book.slug))
+        if 'odt' in formats and book.odt_file:
+            filename = book.odt_file.path
+            archive.write(filename, str('%s.odt' % book.slug))
+        if 'txt' in formats and book.txt_file:
+            filename = book.txt_file.path
+            archive.write(filename, str('%s.txt' % book.slug))
+        if 'mp3' in formats and book.mp3_file:
+            filename = book.mp3_file.path
+            archive.write(filename, str('%s.mp3' % book.slug))
+        if 'ogg' in formats and book.ogg_file:
+            filename = book.ogg_file.path
+            archive.write(filename, str('%s.ogg' % book.slug))
+    archive.close()
+    
+    response = HttpResponse(content_type='application/zip', mimetype='application/x-zip-compressed')
+    response['Content-Disposition'] = 'attachment; filename=%s.zip' % shelf.sort_key
+    response['Content-Length'] = temp.tell()
+    
+    temp.seek(0)
+    response.write(temp.read())
+    return response

 
 

-    return render_to_response('catalogue/fragment_sets.html', locals(),
-        context_instance=RequestContext(request))
+
+@cache.never_cache
+def shelf_book_formats(request, shelf):
+    """"
+    Returns a list of formats of books in shelf.
+    """
+    shelf = get_object_or_404(models.Tag, slug=shelf, category='set')
+
+    formats = {'pdf': False, 'odt': False, 'txt': False, 'mp3': False, 'ogg': False}
+    
+    for book in collect_books(models.Book.tagged.with_all(shelf)):
+        if book.pdf_file:
+            formats['pdf'] = True
+        if book.odt_file:
+            formats['odt'] = True
+        if book.txt_file:
+            formats['txt'] = True
+        if book.mp3_file:
+            formats['mp3'] = True
+        if book.ogg_file:
+            formats['ogg'] = True
+
+    return HttpResponse(LazyEncoder().encode(formats))

 
 
 @login_required
 @require_POST
 
 
 @login_required
 @require_POST

+@cache.never_cache

 def new_set(request):
     new_set_form = forms.NewSetForm(request.POST)
     if new_set_form.is_valid():
         new_set = new_set_form.save(request.user)
 def new_set(request):
     new_set_form = forms.NewSetForm(request.POST)
     if new_set_form.is_valid():
         new_set = new_set_form.save(request.user)

-        
+

         if request.is_ajax():
             return HttpResponse(u'<p>Półka <strong>%s</strong> została utworzona</p>' % new_set)
         else:
             return HttpResponseRedirect('/')
         if request.is_ajax():
             return HttpResponse(u'<p>Półka <strong>%s</strong> została utworzona</p>' % new_set)
         else:
             return HttpResponseRedirect('/')

-    
-    return render_to_response('catalogue/book_sets.html', locals(),
-            context_instance=RequestContext(request))
+
+    return HttpResponseRedirect('/')

 
 
 @login_required
 @require_POST
 
 
 @login_required
 @require_POST

+@cache.never_cache

 def delete_shelf(request, slug):
     user_set = get_object_or_404(models.Tag, slug=slug, category='set', user=request.user)
     user_set.delete()
 def delete_shelf(request, slug):
     user_set = get_object_or_404(models.Tag, slug=slug, category='set', user=request.user)
     user_set.delete()

-    
+

     if request.is_ajax():
         return HttpResponse(u'<p>Półka <strong>%s</strong> została usunięta</p>' % user_set.name)
     else:
         return HttpResponseRedirect('/')
 
 
     if request.is_ajax():
         return HttpResponse(u'<p>Półka <strong>%s</strong> została usunięta</p>' % user_set.name)
     else:
         return HttpResponseRedirect('/')
 
 

+# ==================
+# = Authentication =
+# ==================
+@require_POST
+@cache.never_cache
+def login(request):
+    form = AuthenticationForm(data=request.POST, prefix='login')
+    if form.is_valid():
+        auth.login(request, form.get_user())
+        response_data = {'success': True, 'errors': {}}
+    else:
+        response_data = {'success': False, 'errors': form.errors}
+    return HttpResponse(LazyEncoder(ensure_ascii=False).encode(response_data))
+
+
+@require_POST
+@cache.never_cache
+def register(request):
+    registration_form = UserCreationForm(request.POST, prefix='registration')
+    if registration_form.is_valid():
+        user = registration_form.save()
+        user = auth.authenticate(
+            username=registration_form.cleaned_data['username'], 
+            password=registration_form.cleaned_data['password1']
+        )
+        auth.login(request, user)
+        response_data = {'success': True, 'errors': {}}
+    else:
+        response_data = {'success': False, 'errors': registration_form.errors}
+    return HttpResponse(LazyEncoder(ensure_ascii=False).encode(response_data))
+
+
+@cache.never_cache
+def logout_then_redirect(request):
+    auth.logout(request)
+    return HttpResponseRedirect(request.GET.get('next', '/'))
+
+
+
+# =========
+# = Admin =
+# =========

 @login_required
 @login_required

-def user_shelves(request):
-    shelves = models.Tag.objects.filter(category='set', user=request.user)
-    new_set_form = forms.NewSetForm()
-    return render_to_response('catalogue/user_shelves.html', locals(),
-            context_instance=RequestContext(request))
+@staff_required
+def import_book(request):
+    """docstring for import_book"""
+    book_import_form = forms.BookImportForm(request.POST, request.FILES)
+    if book_import_form.is_valid():
+        try:
+            book_import_form.save()
+        except:
+            info = sys.exc_info()
+            exception = pprint.pformat(info[1])
+            tb = '\n'.join(traceback.format_tb(info[2]))
+            return HttpResponse("An error occurred: %s\n\n%s" % (exception, tb), mimetype='text/plain')
+        return HttpResponse("Book imported successfully")
+    else:
+        return HttpResponse("Error importing file: %r" % book_import_form.errors)
+
+

 
 

+def clock(request):
+    """ Provides server time for jquery.countdown,
+    in a format suitable for Date.parse()
+    """
+    from datetime import datetime
+    return HttpResponse(datetime.now().strftime('%Y/%m/%d %H:%M:%S'))