Orderable List Mixins

gistfile1.py

from leaguejam.apps.manage.org.views import OrgContextMixin
from leaguejam.apps.manage.org.participants.forms import ParticipantSearchForm

from django.views.generic.list import ListView, MultipleObjectMixin
from django.views.generic.edit import FormMixin
from django.db.models import Q

import re

class FormMixinGET(FormMixin):
        
    def get_form_kwargs(self):
        """
            Use get every time
        """
        kwargs = {
                    'initial': self.get_initial(),
                    'data': self.request.GET,
                }
        return kwargs

class ListFilterView(FormMixinGET, ListView):
    """
        Show a filterable list of participants
        
        Uses a form to filter the queryset.
        
        Extenders should provide a get_queryset_from_form_data method
    """
    context_object_name = "object_list"
    
    def get_queryset(self):
        
        # save form to object to pass to context
        self.form = self.get_form(self.get_form_class())
        data = {}
        if self.form.is_valid():
            data = self.form.cleaned_data
        
        return self.get_queryset_from_form_data(data)
    
    def get_queryset_from_form_data(self, data):
        """
            Updates the queryset based on form data.
            Override this
        """
        
        return super(ListFilterView, self).get_queryset()
    
    def get_context_data(self, **kwargs):
        
        _kwargs = {}
        _kwargs.update(kwargs)
        
        # provide the form to the context
        _kwargs['form'] = self.form
        
        # provide the GET Request w/out the page for paging links
        # this is so that we can keep the form submission when we page
        _kwargs['get_request_vars_sans_page'] = re.sub("&?page=\d+", "", self.request.GET.urlencode())
        
        # I have to return this, because FormMixin doesn't use super
        return ListView.get_context_data(self, **_kwargs)
#        return super(ParticipantListView, self).get_context_data(**_kwargs)

class OrderableListMixin(MultipleObjectMixin):
    """
        Uses get_columns, get_ordered_columns, and self.order_queryset_by
        to provide ordering tools
        
        simply use the self.order_queryset_by property in your get_queryset method
    """
    order_queryset_by = None
    
    def get_queryset(self):
        
        if self.request.GET.has_key('order_by'):
            self.order_queryset_by = self.request.GET['order_by']
            
        return self.get_ordered_queryset(self.order_queryset_by)
    
    def get_columns(self):
        """
            Can be overridden to update the columns
            should update self.columns and then call super to keep the update functionality below
            
            columns are in the form:
            [
            {
                        'title': "",    # the title of the column
                        'property': "", # the property to filter by
                        'default': "",  # the default ordering (asc or desc)
                    },
            ]
        """
            
        return []
    
    def get_ordered_columns(self):
        
        _columns = self.get_columns()
        
        # update the column attributes to indicate if they are being used for ordering
        if hasattr(self, "order_queryset_by"):
            
            for c in _columns:
                if self.order_queryset_by == c['property']:
                    c['asc'] = True
                elif self.order_queryset_by == "-%s" % c['property']:
                    c['desc'] = True
        
        return _columns
    
    def get_context_data(self, **kwargs):
        """
            Provides the columns to the context along with the
            get_request_vars_sans_order property to use in links
        """
        _context = super(OrderableListMixin, self).get_context_data(**kwargs)
        
        # provide the GET Request w/out the page for paging links
        get_request_vars = re.sub("&?page=\d+", "", self.request.GET.urlencode())
        _context['get_request_vars_sans_page'] = get_request_vars
        get_request_vars = re.sub("&?order_by=[^&]+", "", get_request_vars)
        _context['get_request_vars_sans_order'] = get_request_vars
                    
        _context['columns'] = self.get_ordered_columns()
        
        qs = _context[self.get_context_object_name(None)]
        
        return _context

class ListFilterOrderView(OrderableListMixin, ListFilterView):
    """
    
    """
    def get_context_data(self, **kwargs):
        
        _context = {}
        _context.update(OrderableListMixin.get_context_data(self, **kwargs))
        _context.update(ListFilterView.get_context_data(self, **kwargs))
        return _context
        
    def get_ordered_queryset(self, order_by):
        """
            Use the ListFilterView get_queryset method
            so the form is processed
        """
        return self.order_queryset(ListFilterView.get_queryset(self), order_by)
    
    def order_queryset(self, qs, order_by):
        
        if order_by:
            qs = qs.order_by(order_by)
        return qs
        

Columns in template:

{% for column in columns %}
    <th>
        {% if column.property %}
            <a
                href='?{{ get_request_vars_sans_order }}&order_by={% if column.asc %}-{% else %}{% if not column.asc and not column.desc and column.default == "desc" %}-{% endif %}{% endif %}{{ column.property }}'
                title='Sort by {{ column.title }}'>
                    {{ column.title }}
            {% if column.asc %}
                <img src='/static/images/icons/bullet_arrow_up.png' alt='^'/>
            {% endif %}{% if column.desc %}
                <img src='/static/images/icons/bullet_arrow_down.png' alt='' />
            {% endif %}
            </a>
        {% else %}
            {{ column.title }}
        {% endif %}
    </th>
{% endfor %}