Python | Django | class-based viewsのRedirectViewの使い方

2021年8月22日2024年9月12日

公開日：2021/8/22

Pythonには，DjangoというWebアプリケーションフレームワークがある．フレームワークのため，Djangoを利用するとWebアプリを通常よりも短時間で開発することが可能になる．

class-based viewsは，viewsを実装する手段の1つであり，関数の代わりにPythonのオブジェクトとしてviewsを定義する．viewsの作成とデータの追加・更新・削除が容易になる．

前記事では，「class-based viewsのFormViewの使い方」を作成した．前記事での設定をそのまま引き継いだ上で，本記事では，「class-based viewsのRedirectViewの使い方」を以下5つの構成にて記す．

◆実施環境

Python 3.8.8
Django 3.2.3
VS Code 1.59.0

■class-based viewsのRedirectViewの使い方

与えられたURLにリダイレクトさせる際にRedirectViewが利用される．

基本の利用1

“ec_site/urls.py"に追記し，以下のように編集する．

from django.urls import path
from .views import (
    TopView, HomeView, MedicineDetailView,
    MedicineListView, MedicineCreateView,
    MedicineUpdateView, MedicineDeleteView,
    MedicineFormView,
    )
from django.views.generic.base import RedirectView # 追記箇所

app_name = 'ec_site'

urlpatterns = [
    path('top/', TopView.as_view(), name='top'),
    path('home/', HomeView.as_view(), name='home'),
    path('detail_medicine/', MedicineDetailView.as_view(), name='detail_medicine'),
    path('list_medicines', MedicineListView.as_view(), name='list_medicines'),
    path('list_medicines/', MedicineListView.as_view(), name='list_medicines'),
    path('insert_medicine/', MedicineCreateView.as_view(), name='insert_medicine'),
    path('update_medicine/', MedicineUpdateView.as_view(), name='update_medicine'),
    path('delete_medicine/', MedicineDeleteView.as_view(), name='delete_medicine'),
    path('form_medicine/', MedicineFormView.as_view(), name='form_medicine'),
    path('shelokuma/', RedirectView.as_view(url='https://shelokuma.com')), # 追記箇所
]

VS Codeの"View"を開き，"Terminal"をクリックする．クリックするとVS Codeの下部にターミナルが開くので，”conda activate 仮想環境名”を実行し，仮想環境に移行する(移行方法の詳細はこちら)．その後，ターミナルで"cd class_based_view"を入力し，ディレクトリを変更する．変更後，以下のように”python manage.py runserver”を実行する．以下が出力される．

(djangoenv) C:\Users\shiro\Desktop\210517_python development\myclassbasedviewtest\class_based_view
>python manage.py runserver
Watching for file changes with StatReloader
Performing system checks...

System check identified no issues (0 silenced). # 以下出力箇所
August 22, 2021 - 17:40:02
Django version 3.2.3, using settings 'class_based_view.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CTRL-BREAK.

上記の"http://127.0.0.1:8000/"をクリックすると，ブラウザが開き，以下画面が出力される．

ブラウザのURLに"http://127.0.0.1:8000/ec_site/shelokuma"と入力すると，以下ページ(https://shelokuma.com)に遷移する．

基本の利用2

“ec_site/views.py"に追記し，以下のように編集する．

from django.shortcuts import render
from django.views.generic.base import ( # 変更箇所
    View, TemplateView, RedirectView,
)
from django.views.generic.detail import DetailView
from django.views.generic.list import ListView
from django.views.generic.edit import (
    CreateView, UpdateView, DeleteView,
    FormView,
)
from . import forms
import random
from .models import Medicines
from datetime import datetime
from django.urls import reverse_lazy

class TopView(View):

    def get(self, request, *args, **kwargs):
        medicine_form = forms.MedicineForm()
        return render(request, 'top.html', context={
            'medicine_form': medicine_form,
        })

    def post(self, request, *args, **kwargs):
        medicine_form = forms.MedicineForm(request.POST or None)
        if medicine_form.is_valid():
            medicine_form.save()
        return render(request, 'top.html', context={
            'medicine_form': medicine_form,
        })

class HomeView(TemplateView):

    template_name = 'home.html'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['name'] = kwargs.get('name')
        context['alphabet'] = random.randint(0,9999)
        return context

class MedicineDetailView(DetailView):
    model = Medicines
    template_name = 'medicine.html'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['time'] = datetime.now()
        return context

class MedicineListView(ListView):
    model = Medicines
    template_name = 'medicine_list.html'

    def get_queryset(self):
        qs = super(MedicineListView, self).get_queryset()
        if 'name' in self.kwargs:
            qs = qs.filter(name__startswith=self.kwargs['name'])
        qs = qs.order_by('-id')
        return qs

class MedicineCreateView(CreateView):
    model = Medicines
    fields = ['name', 'description', 'price']
    template_name = 'insert_medicine.html'

    def form_valid(self, form):
        form.instance.create_time = datetime.now()
        form.instance.update_time = datetime.now()
        return super(MedicineCreateView, self).form_valid(form)

    def get_initial(self, **kwargs):
        initial = super(MedicineCreateView, self).get_initial(**kwargs)
        initial['price'] = '1000'
        return initial

class MedicineUpdateView(UpdateView):
    template_name = 'update_medicine.html'
    model = Medicines
    form_class = forms.MedicineUpdateForm

class MedicineDeleteView(DeleteView):
    model = Medicines
    template_name = 'delete_medicine.html'
    success_url = reverse_lazy('ec_site:list_medicines')

class MedicineFormView(FormView):

    template_name = 'form_medicine.html'
    form_class = forms.MedicineForm
    success_url = reverse_lazy('ec_site:list_medicines')

    def get_initial(self):
        initial = super(MedicineFormView, self).get_initial()
        initial['price'] = '2000'
        return initial

    def form_valid(self, form):
        if form.is_valid():
            form.save()
        return super(MedicineFormView, self).form_valid(form)

class MedicineRedirectView(RedirectView): # 以下追記箇所
    url = 'https://shelokuma.com'

“ec_site/urls.py"に追記し，以下のように編集する．

from django.urls import path
from .views import ( # 変更箇所
    TopView, HomeView, MedicineDetailView,
    MedicineListView, MedicineCreateView,
    MedicineUpdateView, MedicineDeleteView,
    MedicineFormView, MedicineRedirectView,
    )
from django.views.generic.base import RedirectView

app_name = 'ec_site'

urlpatterns = [
    path('top/', TopView.as_view(), name='top'),
    path('home/', HomeView.as_view(), name='home'),
    path('detail_medicine/', MedicineDetailView.as_view(), name='detail_medicine'),
    path('list_medicines', MedicineListView.as_view(), name='list_medicines'),
    path('list_medicines/', MedicineListView.as_view(), name='list_medicines'),
    path('insert_medicine/', MedicineCreateView.as_view(), name='insert_medicine'),
    path('update_medicine/', MedicineUpdateView.as_view(), name='update_medicine'),
    path('delete_medicine/', MedicineDeleteView.as_view(), name='delete_medicine'),
    path('form_medicine/', MedicineFormView.as_view(), name='form_medicine'),
    path('shelokuma/', RedirectView.as_view(url='https://shelokuma.com')),
    path('redirectview_medicine/', MedicineRedirectView.as_view(), name='redirectview_medicine'), # 追記箇所
]

ターミナルを開き，仮想環境に移行し，"cd class_based_view"のディレクトリにて，”python manage.py runserver”を実行する．"http://127.0.0.1:8000/"をクリックすると，ブラウザが開くので，URLに"http://127.0.0.1:8000/ec_site/redirectview_medicine"と入力すると，以下ページ(https://shelokuma.com)に遷移する．

“redirect"を利用した編集画面への移行

“ec_site/views.py"に追記し，以下のように編集する．

from django.shortcuts import render
from django.views.generic.base import (
    View, TemplateView, RedirectView,
)
from django.views.generic.detail import DetailView
from django.views.generic.list import ListView
from django.views.generic.edit import (
    CreateView, UpdateView, DeleteView,
    FormView,
)
from . import forms
import random
from .models import Medicines
from datetime import datetime
from django.urls import reverse_lazy

class TopView(View):

    def get(self, request, *args, **kwargs):
        medicine_form = forms.MedicineForm()
        return render(request, 'top.html', context={
            'medicine_form': medicine_form,
        })

    def post(self, request, *args, **kwargs):
        medicine_form = forms.MedicineForm(request.POST or None)
        if medicine_form.is_valid():
            medicine_form.save()
        return render(request, 'top.html', context={
            'medicine_form': medicine_form,
        })

class HomeView(TemplateView):

    template_name = 'home.html'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['name'] = kwargs.get('name')
        context['alphabet'] = random.randint(0,9999)
        return context

class MedicineDetailView(DetailView):
    model = Medicines
    template_name = 'medicine.html'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['time'] = datetime.now()
        return context

class MedicineListView(ListView):
    model = Medicines
    template_name = 'medicine_list.html'

    def get_queryset(self):
        qs = super(MedicineListView, self).get_queryset()
        if 'name' in self.kwargs:
            qs = qs.filter(name__startswith=self.kwargs['name'])
        qs = qs.order_by('-id')
        return qs

class MedicineCreateView(CreateView):
    model = Medicines
    fields = ['name', 'description', 'price']
    template_name = 'insert_medicine.html'

    def form_valid(self, form):
        form.instance.create_time = datetime.now()
        form.instance.update_time = datetime.now()
        return super(MedicineCreateView, self).form_valid(form)

    def get_initial(self, **kwargs):
        initial = super(MedicineCreateView, self).get_initial(**kwargs)
        initial['price'] = '1000'
        return initial

class MedicineUpdateView(UpdateView):
    template_name = 'update_medicine.html'
    model = Medicines
    form_class = forms.MedicineUpdateForm

class MedicineDeleteView(DeleteView):
    model = Medicines
    template_name = 'delete_medicine.html'
    success_url = reverse_lazy('ec_site:list_medicines')

class MedicineFormView(FormView):

    template_name = 'form_medicine.html'
    form_class = forms.MedicineForm
    success_url = reverse_lazy('ec_site:list_medicines')

    def get_initial(self):
        initial = super(MedicineFormView, self).get_initial()
        initial['price'] = '2000'
        return initial

    def form_valid(self, form):
        if form.is_valid():
            form.save()
        return super(MedicineFormView, self).form_valid(form)

class MedicineRedirectView(RedirectView):
    url = 'https://shelokuma.com'

    def get_redirect_url(self, *args, **kwargs): # 以下追記箇所
        medicine = Medicines.objects.first()
        return reverse_lazy('ec_site:update_medicine', kwargs={'pk': medicine.pk})

上記を保存し，ブラウザにて"http://127.0.0.1:8000/ec_site/redirectview_medicine"と入力すると，以下の編集ページ(pkが最大：最新ページ)に遷移する．

“redirect"を利用した詳細画面への移行

“ec_site/urls.py"に追記し，以下のように編集する．

from django.urls import path
from .views import (
    TopView, HomeView, MedicineDetailView,
    MedicineListView, MedicineCreateView,
    MedicineUpdateView, MedicineDeleteView,
    MedicineFormView, MedicineRedirectView,
    )
from django.views.generic.base import RedirectView

app_name = 'ec_site'

urlpatterns = [
    path('top/', TopView.as_view(), name='top'),
    path('home/', HomeView.as_view(), name='home'),
    path('detail_medicine/', MedicineDetailView.as_view(), name='detail_medicine'),
    path('list_medicines', MedicineListView.as_view(), name='list_medicines'),
    path('list_medicines/', MedicineListView.as_view(), name='list_medicines'),
    path('insert_medicine/', MedicineCreateView.as_view(), name='insert_medicine'),
    path('update_medicine/', MedicineUpdateView.as_view(), name='update_medicine'),
    path('delete_medicine/', MedicineDeleteView.as_view(), name='delete_medicine'),
    path('form_medicine/', MedicineFormView.as_view(), name='form_medicine'),
    path('shelokuma/', RedirectView.as_view(url='https://shelokuma.com')),
    path('redirectview_medicine/', MedicineRedirectView.as_view(), name='redirectview_medicine'),
    path('redirectview_medicine/', MedicineRedirectView.as_view(), name='redirectview_medicine'), # 追記箇所
]

“ec_site/views.py"に追記し，以下のように編集する．

from django.shortcuts import render
from django.views.generic.base import (
    View, TemplateView, RedirectView,
)
from django.views.generic.detail import DetailView
from django.views.generic.list import ListView
from django.views.generic.edit import (
    CreateView, UpdateView, DeleteView,
    FormView,
)
from . import forms
import random
from .models import Medicines
from datetime import datetime
from django.urls import reverse_lazy

class TopView(View):

    def get(self, request, *args, **kwargs):
        medicine_form = forms.MedicineForm()
        return render(request, 'top.html', context={
            'medicine_form': medicine_form,
        })

    def post(self, request, *args, **kwargs):
        medicine_form = forms.MedicineForm(request.POST or None)
        if medicine_form.is_valid():
            medicine_form.save()
        return render(request, 'top.html', context={
            'medicine_form': medicine_form,
        })

class HomeView(TemplateView):

    template_name = 'home.html'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['name'] = kwargs.get('name')
        context['alphabet'] = random.randint(0,9999)
        return context

class MedicineDetailView(DetailView):
    model = Medicines
    template_name = 'medicine.html'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['time'] = datetime.now()
        return context

class MedicineListView(ListView):
    model = Medicines
    template_name = 'medicine_list.html'

    def get_queryset(self):
        qs = super(MedicineListView, self).get_queryset()
        if 'name' in self.kwargs:
            qs = qs.filter(name__startswith=self.kwargs['name'])
        qs = qs.order_by('-id')
        return qs

class MedicineCreateView(CreateView):
    model = Medicines
    fields = ['name', 'description', 'price']
    template_name = 'insert_medicine.html'
    # success_url = reverse_lazy('ec_site:list_medicines')

    def form_valid(self, form):
        form.instance.create_time = datetime.now()
        form.instance.update_time = datetime.now()
        return super(MedicineCreateView, self).form_valid(form)

    def get_initial(self, **kwargs):
        initial = super(MedicineCreateView, self).get_initial(**kwargs)
        initial['price'] = '1000'
        return initial

class MedicineUpdateView(UpdateView):
    template_name = 'update_medicine.html'
    model = Medicines
    form_class = forms.MedicineUpdateForm

class MedicineDeleteView(DeleteView):
    model = Medicines
    template_name = 'delete_medicine.html'
    success_url = reverse_lazy('ec_site:list_medicines')

class MedicineFormView(FormView):

    template_name = 'form_medicine.html'
    form_class = forms.MedicineForm
    success_url = reverse_lazy('ec_site:list_medicines')

    def get_initial(self):
        initial = super(MedicineFormView, self).get_initial()
        initial['price'] = '2000'
        return initial

    def form_valid(self, form):
        if form.is_valid():
            form.save()
        return super(MedicineFormView, self).form_valid(form)

class MedicineRedirectView(RedirectView):
    url = 'https://shelokuma.com'

    def get_redirect_url(self, *args, **kwargs):
        medicine = Medicines.objects.last()
        if 'pk' in kwargs: # 追記箇所(110～111行目)
            return reverse_lazy('ec_site:detail_medicine', kwargs={'pk':kwargs['pk']})
        
        return reverse_lazy('ec_site:update_medicine', kwargs={'pk': medicine.pk})

上記を保存し，ブラウザにて"http://127.0.0.1:8000/ec_site/redirectview_medicine/"の後ろに数字を記載すると，以下のように詳細ページに遷移する．今回は"1″を入力した．

参照

https://docs.djangoproject.com/ja/3.2/ref/class-based-views/base/#redirectview

以上

Pythonclass-based views,Django,RedirectView,クラスベースビュー

Posted by クマガイ