add MEDIA_URL variable in templatetags, so that pagination template can use images
[django-pagination.git] / pagination / templatetags / pagination_tags.py
index 6db06ba..3733434 100644 (file)
@@ -2,84 +2,143 @@ try:
     set
 except NameError:
     from sets import Set as set
+
 from django import template
-from pagination.registration import get_registry, default_pagination
-registry = get_registry()
-from django.db.models.query import QuerySet
-from django.core.paginator import Paginator, QuerySetPaginator, InvalidPage
-#from django.template.loader import render_to_string
+from django.http import Http404
+from django.core.paginator import Paginator, InvalidPage
+from django.conf import settings
 
 register = template.Library()
 
+DEFAULT_PAGINATION = getattr(settings, 'PAGINATION_DEFAULT_PAGINATION', 20)
+DEFAULT_WINDOW = getattr(settings, 'PAGINATION_DEFAULT_WINDOW', 4)
+DEFAULT_ORPHANS = getattr(settings, 'PAGINATION_DEFAULT_ORPHANS', 0)
+INVALID_PAGE_RAISES_404 = getattr(settings,
+    'PAGINATION_INVALID_PAGE_RAISES_404', False)
+
 def do_autopaginate(parser, token):
+    """
+    Splits the arguments to the autopaginate tag and formats them correctly.
+    """
     split = token.split_contents()
-    if len(split) == 1:
-        return AutoPaginateNode()
-    elif len(split) == 2:
-        return AutoPaginateNode(queryset_var=split[1])
+    as_index = None
+    context_var = None
+    for i, bit in enumerate(split):
+        if bit == 'as':
+            as_index = i
+            break
+    if as_index is not None:
+        try:
+            context_var = split[as_index + 1]
+        except IndexError:
+            raise template.TemplateSyntaxError("Context variable assignment " +
+                "must take the form of {%% %r object.example_set.all ... as " +
+                "context_var_name %%}" % split[0])
+        del split[as_index:as_index + 2]
+    if len(split) == 2:
+        return AutoPaginateNode(split[1])
+    elif len(split) == 3:
+        return AutoPaginateNode(split[1], paginate_by=split[2], 
+            context_var=context_var)
+    elif len(split) == 4:
+        try:
+            orphans = int(split[3])
+        except ValueError:
+            raise template.TemplateSyntaxError(u'Got %s, but expected integer.'
+                % split[3])
+        return AutoPaginateNode(split[1], paginate_by=split[2], orphans=orphans,
+            context_var=context_var)
     else:
-        raise template.TemplateSyntaxError('%r tag takes only one optional argument.' % split[0])
+        raise template.TemplateSyntaxError('%r tag takes one required ' +
+            'argument and one optional argument' % split[0])
 
 class AutoPaginateNode(template.Node):
-    def __init__(self, queryset_var=None):
-        if queryset_var:
-            self.queryset_var = template.Variable(queryset_var)
+    """
+    Emits the required objects to allow for Digg-style pagination.
+    
+    First, it looks in the current context for the variable specified, and using
+    that object, it emits a simple ``Paginator`` and the current page object 
+    into the context names ``paginator`` and ``page_obj``, respectively.
+    
+    It will then replace the variable specified with only the objects for the
+    current page.
+    
+    .. note::
+        
+        It is recommended to use *{% paginate %}* after using the autopaginate
+        tag.  If you choose not to use *{% paginate %}*, make sure to display the
+        list of available pages, or else the application may seem to be buggy.
+    """
+    def __init__(self, queryset_var, paginate_by=DEFAULT_PAGINATION,
+        orphans=DEFAULT_ORPHANS, context_var=None):
+        self.queryset_var = template.Variable(queryset_var)
+        if isinstance(paginate_by, int):
+            self.paginate_by = paginate_by
         else:
-            self.queryset_var = None
+            self.paginate_by = template.Variable(paginate_by)
+        self.orphans = orphans
+        self.context_var = context_var
 
     def render(self, context):
-        if self.queryset_var is not None:
-            try:
-                key = self.queryset_var.var
-                value = self.queryset_var.resolve(context)
-                if issubclass(value.__class__, QuerySet):
-                    model = value.model
-                    paginator_class = QuerySetPaginator
-                else:
-                    value = list(value)
-                    try:
-                        model = value[0].__class__
-                    except IndexError:
-                        return u''
-                    paginator_class = Paginator
-                pagination = registry.get_for_model(model)
-                if pagination is None:
-                    pagination = default_pagination
-                paginator = paginator_class(value, pagination)
-                try:
-                    page_obj = paginator.page(context['request'].page)
-                except:
-                    return u''
-                context[key] = page_obj.object_list
-                context['paginator'] = paginator
-                context['page_obj'] = page_obj
-                return u''
-            except template.VariableDoesNotExist:
-                pass
-        for d in context:
-            for key, value in d.iteritems():
-                if issubclass(value.__class__, QuerySet):
-                    model = value.model
-                    pagination = registry.get_for_model(model)
-                    if pagination is not None:
-                        paginator = QuerySetPaginator(value, pagination)
-                        try:
-                            page_obj = paginator.page(context['request'].page)
-                        except:
-                            return u''
-                        context[key] = page_obj.object_list
-                        context['paginator'] = paginator
-                        context['page_obj'] = page_obj
-                        return u''
+        key = self.queryset_var.var
+        value = self.queryset_var.resolve(context)
+        if isinstance(self.paginate_by, int):
+            paginate_by = self.paginate_by
+        else:
+            paginate_by = self.paginate_by.resolve(context)
+        paginator = Paginator(value, paginate_by, self.orphans)
+        try:
+            page_obj = paginator.page(context['request'].page)
+        except InvalidPage:
+            if INVALID_PAGE_RAISES_404:
+                raise Http404('Invalid page requested.  If DEBUG were set to ' +
+                    'False, an HTTP 404 page would have been shown instead.')
+            context[key] = []
+            context['invalid_page'] = True
+            return u''
+        if self.context_var is not None:
+            context[self.context_var] = page_obj.object_list
+        else:
+            context[key] = page_obj.object_list
+        context['paginator'] = paginator
+        context['page_obj'] = page_obj
         return u''
 
-def paginate(context, window=4):
+def paginate(context, window=DEFAULT_WINDOW):
+    """
+    Renders the ``pagination/pagination.html`` template, resulting in a
+    Digg-like display of the available pages, given the current page.  If there
+    are too many pages to be displayed before and after the current page, then
+    elipses will be used to indicate the undisplayed gap between page numbers.
+    
+    Requires one argument, ``context``, which should be a dictionary-like data
+    structure and must contain the following keys:
+    
+    ``paginator``
+        A ``Paginator`` or ``QuerySetPaginator`` object.
+    
+    ``page_obj``
+        This should be the result of calling the page method on the 
+        aforementioned ``Paginator`` or ``QuerySetPaginator`` object, given
+        the current page.
+    
+    This same ``context`` dictionary-like data structure may also include:
+    
+    ``getvars``
+        A dictionary of all of the **GET** parameters in the current request.
+        This is useful to maintain certain types of state, even when requesting
+        a different page.
+        """
     try:
         paginator = context['paginator']
         page_obj = context['page_obj']
         page_range = paginator.page_range
+        # First and last are simply the first *n* pages and the last *n* pages,
+        # where *n* is the current window size.
         first = set(page_range[:window])
         last = set(page_range[-window:])
+        # Now we look around our current page, making sure that we don't wrap
+        # around.
         current_start = page_obj.number-1-window
         if current_start < 0:
             current_start = 0
@@ -88,44 +147,76 @@ def paginate(context, window=4):
             current_end = 0
         current = set(page_range[current_start:current_end])
         pages = []
+        # If there's no overlap between the first set of pages and the current
+        # set of pages, then there's a possible need for elusion.
         if len(first.intersection(current)) == 0:
-            first_list = sorted(list(first))
-            second_list = sorted(list(current))
+            first_list = list(first)
+            first_list.sort()
+            second_list = list(current)
+            second_list.sort()
             pages.extend(first_list)
-            diff = second_list[0] - first_list[-1] 
+            diff = second_list[0] - first_list[-1]
+            # If there is a gap of two, between the last page of the first
+            # set and the first page of the current set, then we're missing a
+            # page.
             if diff == 2:
                 pages.append(second_list[0] - 1)
+            # If the difference is just one, then there's nothing to be done,
+            # as the pages need no elusion and are correct.
             elif diff == 1:
                 pass
+            # Otherwise, there's a bigger gap which needs to be signaled for
+            # elusion, by pushing a None value to the page list.
             else:
                 pages.append(None)
             pages.extend(second_list)
         else:
-            pages.extend(sorted(list(first.union(current))))
+            unioned = list(first.union(current))
+            unioned.sort()
+            pages.extend(unioned)
+        # If there's no overlap between the current set of pages and the last
+        # set of pages, then there's a possible need for elusion.
         if len(current.intersection(last)) == 0:
-            second_list = sorted(list(last))
+            second_list = list(last)
+            second_list.sort()
             diff = second_list[0] - pages[-1]
+            # If there is a gap of two, between the last page of the current
+            # set and the first page of the last set, then we're missing a 
+            # page.
             if diff == 2:
                 pages.append(second_list[0] - 1)
+            # If the difference is just one, then there's nothing to be done,
+            # as the pages need no elusion and are correct.
             elif diff == 1:
                 pass
+            # Otherwise, there's a bigger gap which needs to be signaled for
+            # elusion, by pushing a None value to the page list.
             else:
                 pages.append(None)
             pages.extend(second_list)
         else:
-            pages.extend(sorted(list(last.difference(current))))
-        
-        getvars = context['request'].GET.copy()
-        if 'page' in getvars:
-            del getvars['page']
-        return {
+            differenced = list(last.difference(current))
+            differenced.sort()
+            pages.extend(differenced)
+        to_return = {
+            'MEDIA_URL': settings.MEDIA_URL,
             'pages': pages,
             'page_obj': page_obj,
             'paginator': paginator,
             'is_paginated': paginator.count > paginator.per_page,
-            'getvars': "&%s" % getvars.urlencode()
         }
-    except KeyError:
-        return u''
-register.inclusion_tag('pagination/pagination.html', takes_context=True)(paginate)
-register.tag('autopaginate', do_autopaginate)
\ No newline at end of file
+        if 'request' in context:
+            getvars = context['request'].GET.copy()
+            if 'page' in getvars:
+                del getvars['page']
+            if len(getvars.keys()) > 0:
+                to_return['getvars'] = "&%s" % getvars.urlencode()
+            else:
+                to_return['getvars'] = ''
+        return to_return
+    except KeyError, AttributeError:
+        return {}
+
+register.inclusion_tag('pagination/pagination.html', takes_context=True)(
+    paginate)
+register.tag('autopaginate', do_autopaginate)