Django Tables - Column Filtering

Question

I started using django-tables2 (which I can highly recommend from the first impression) and I m asking myself how to implement column filtering. I do not find the appropriate documentation for it, but I m sure it is somewhere out there.

Answer 1

A little late answer but anyway ... I also couldn't find any appropriate documentation for column filtering. There are many methods to do it:

A. By hand: I add a form containing the fields I'd like to filter with and then I do something like this in my view:

  data = models.MyClass.all()
  form = forms.MyFilterForm(request.GET)
  if request.GET.get('field1'):
    data = data.filter(field1=request.GET.get('field1') )
  if request.GET.get('field2'):
    data = data.filter(field2=request.GET.get('field2') )   
  ...
  table = tables.MyTable(data)

This works very nice however it's not so DRY because it is hard coded in the view.

B. Using a SingleTableView: Another way is to add a SingleTableView that contains the form:

from django_tables2 import SingleTableView
class FilteredSingleTableView(SingleTableView):
  def get_table_data(self):
    data= models.MyClass.objects.all
    if self.request.GET.get('field1'):
      data = data.filter(field1=self.request.GET.get('field1') )
    if self.request.GET.get('field1'):
      data = data.filter(field1=self.request.GET.get('field1') )
    return data

    def get_context_data(self, **kwargs):
      context = super(FilteredSingleTableView, self).get_context_data(**kwargs)
      context['form'] = forms.MyFilterForm(self.request.user, self.request.GET)
      return context

This is more DRY :)

C. Using SingleTableView and django_filters: This probably is the most DRY way :) Here's how to do it:

First define a filter:

class MyFilter(django_filters.FilterSet):
  field1 = django_filters.CharFilter()
  field2 = django_filters.CharFilter()
...

(or you can add a model filter in Meta ( model = MyModel)

Now, create a SingleTableView like this

class FilteredSingleTableView(SingleTableView):
  def get_table_data(self):
    f = filters.MyFilter(self.request.GET, queryset =models.MyClass.objects.all() , request=self.request )
    return f

  def get_context_data(self, **kwargs):
    context = super(FilteredSingleTableView, self).get_context_data(**kwargs)
    f = filters.MyFilter(self.request.GET, queryset =models.MyClass.objects.all() , request=self.request )
    context['form'] = f.form
    return context

(probably there is a problem with the line f =... but I couldn't make it work otherwise.

Finally, you can call the SingleTableView from your urls.py like this

url(r'^$', views.FilteredSingleTableView.as_view(
    table_class = tables.MyTable, 
    model=models.MyClass, 
    template_name ='mytemplate.html', 
    table_pagination={ "per_page":50 } )) , 
    name='filtered_single_table_view'
),

D. Using a generic class: This is an even more DRY and django-generic-class-views like way! This is actually the next step from C: Just declare your FilteredSingleTableView like this:

class FilteredSingleTableView(django_tables2.SingleTableView):
  filter_class = None

  def get_table_data(self):
    self.filter = self.filter_class(self.request.GET, queryset =super(FilteredSingleTableView, self).get_table_data() )
    return self.filter.qs

  def get_context_data(self, **kwargs):
    context = super(FilteredSingleTableView, self).get_context_data(**kwargs)
    context['filter'] = self.filter
    return context

Now the FilteredSingleTableView has a parameter for the class of the filter so you may pass it in your urls.py among the other parameters:

    url(r'^$', ships.views.FilteredSingleTableView.as_view(
        model=models.MyModel,
        table_class=tables.MyTable, 
        template_name='mytemplate.html' , 
        filter_class = filters.MyFilter, 
    ) , name='myview'),

So you can use FilteredSingleTableView without modifications for filtering any of your models !!

Also notice that I've now saved the filter as an instance variable and removed the repetitive code f=filters.MyFilter(...) that I had in C (get_table_data is called before get_context_data - if that was not always the case then we could add an get_filter instance method that would do the trick) !

Update 23/04/2016: After popular demand, I've created a simple Django project that uses the generic FilteredSingleTableView class to filter a table of books. You may find it out at: https://github.com/spapas/django_table_filtering

Update 05/07/2016: Please notice that you should use return self.filter.qs for the get_table_data return in D (I've alread updated the answer with this) or else the view will take too long to render for big tables -- more info can be found on https://github.com/spapas/django_table_filtering/issues/1

Answer 2

There is an easier and DRYer way to build a generic view do this:

from django_filters.views import FilterView
from django_tables2 import SingleTableView


class FilterTableView(FilterView, SingleTableView):   
    def get_table_data(self):
        return self.object_list

So you can do this:

class MyTableView(FilterTableView):
    model = MyModel
    table_class = MyTable
    filterset_class = MyFilter

Answer 3

This is a complete working example from an app I'm writing using Django 2, Crispy Forms and Bootstrap 4:

urls.py:

from django.urls import path
from .views import ASTodasView


urlpatterns = [
    path("asignatura/todas", ASTodasView.as_view(), name="as-todas"),
]

views.py:

from .filters import AsignaturaListFilter
from .forms import AsignaturaFilterFormHelper
from .models import Asignatura, Calendario
from .tables import AsignaturasTable
from .utils import PagedFilteredTableView


class ASTodasView(PagedFilteredTableView):
    filter_class = AsignaturaListFilter
    model = Asignatura
    table_class = AsignaturasTable
    template_name = "asignatura/todas.html"
    formhelper_class = AsignaturaFilterFormHelper

    def get_queryset(self):
        anyo_academico = Calendario.get_anyo_academico_actual()
        return Asignatura.objects.filter(anyo_academico=anyo_academico)

filters.py:

import django_filters
from .models import Asignatura


class AsignaturaListFilter(django_filters.FilterSet):
    class Meta:
        model = Asignatura
        fields = {
            "nombre_estudio": ["icontains"],
            "nombre_centro": ["icontains"],
            "asignatura_id": ["exact"],
            "nombre_asignatura": ["icontains"],
            "cod_grupo_asignatura": ["exact"],
        }
        order_by = ["asignatura_id"]

forms.py:

from django import forms
from django.utils.translation import gettext_lazy as _

from crispy_forms.bootstrap import FormActions, InlineField
from crispy_forms.helper import FormHelper
from crispy_forms.layout import Div, Fieldset, Layout, Submit


class AsignaturaFilterFormHelper(FormHelper):
    # See https://django-crispy-forms.readthedocs.io/en/latest/form_helper.html

    form_class = "form form-inline"
    form_id = "asignatura-search-form"
    form_method = "GET"
    form_tag = True
    html5_required = True
    layout = Layout(
        Div(
            Fieldset(
                "<span class='fa fa-search'></span> " + str(_("Buscar asignatura")),
                Div(
                    InlineField("nombre_estudio__icontains", wrapper_class="col-4"),
                    InlineField("nombre_centro__icontains", wrapper_class="col-4"),
                    InlineField("asignatura_id", wrapper_class="col-4"),
                    InlineField("nombre_asignatura__icontains", wrapper_class="col-4"),
                    InlineField("cod_grupo_asignatura", wrapper_class="col-4"),
                    css_class="row",
                ),
                css_class="col-10 border p-3",
            ),
            FormActions(
                Submit("submit", _("Filtrar")),
                css_class="col-2 text-right align-self-center",
            ),
            css_class="row",
        )
    )

tables.py:

import django_tables2 as tables
from django.utils.translation import gettext_lazy as _

from .models import Asignatura


class AsignaturasTable(tables.Table):
    class Meta:
        attrs = {"class": "table table-striped table-hover cabecera-azul"}
        model = Asignatura
        fields = (
            "nombre_estudio",
            "nombre_centro",
            "asignatura_id",
            "nombre_asignatura",
            "cod_grupo_asignatura",
        )
        empty_text = _(
            "No hay ninguna asignatura que satisfaga los criterios de búsqueda."
        )
        template_name = "django_tables2/bootstrap4.html"
        per_page = 20

utils.py:

from django_tables2 import SingleTableView


class PagedFilteredTableView(SingleTableView):
    filter_class = None
    formhelper_class = None
    context_filter_name = "filter"

    def get_table_data(self):
        self.filter = self.filter_class(
            self.request.GET, queryset=super().get_table_data()
        )
        self.filter.form.helper = self.formhelper_class()
        return self.filter.qs

    def get_context_data(self, **kwargs):
        context = super(PagedFilteredTableView, self).get_context_data(**kwargs)
        context[self.context_filter_name] = self.filter
        return context

todas.html:

{% extends 'base.html' %}
{% load crispy_forms_tags i18n %}
{% load render_table from django_tables2 %}

{% block title %}{% trans "Todas las asignaturas" %}{% endblock title %}

{% block content %}
<div class="container-blanco">
  <h1>{% trans "Todas las asignaturas" %}</h1>
  <hr />
  <br />

  {% crispy filter.form filter.form.helper %}
  <br />
  {% render_table table %}
</div>
{% endblock content %}

Hope it helps. Improvements are welcome.