Django 활용하기(2)

뷰 (views) 와 템플릿 (templates)

• order_by()
  • 쿼리셋을 정렬하기 위한 메서드로 특정한 필드를 기준으로 오름차순 or 내림차순의 형태로 정렬가능
  • order_by() 뒤에 슬라이싱 [:]을 통해 범위 지정 가능
• render()
  • HTTP 요청을 받아 원하는 템플릿 파일을 렌더링하여 응답
  • 인자로써는 request, 템플릿 파일 경로, Context 순으로 변수를 받음

# polls/views.py

def index(request):
    # Question 목록에서 order_by를 통해 5개의 목록을 가지고 옴
    latest_question_list = Question.objects.order_by('-pub_date')[:5]
    context = {'first_question': latest_question_list[0]}
    return render(request, 'polls/index.html', context)
    
# polls/templates/polls/index.html

<ul>
    <li>{{first question}}</li>
</ul>

---

template 조건, 반복문 작성

# polls/templates/polls/index.html

{% questions %}
<ul>
    {% for question in questions%}
        <li>{{question}}</li>
    {% endfor %}
</ul>
{% else %}
<p> no questions </p>
{% endif %}

# polls/views.py

from .models import *
from django.shortcuts import render

def index(request):
    latest_question_list = Question.objects.order_by('-pub_date')[:5]
    context = {'questions': latest_question_list}
    #context = {'questions': []}
    return render(request, 'polls/index.html', context)

---

404 에러 처리하기

 

polls/views.py

from models.py import *
from django.http import HttpResponse
from django.http import Http404
from django.shortcuts import render, get_objects_or_404

...
def detail(request, question_id):
   # try:
       # quetion = Question.objects.get(pk=quesion_id)
   # except Question.DoesNotExist:
       # raise Http404("Question does not exist")
       
   question = get_object_or_404(Question, pk=question_id)
   return render(request, 'polls/detail.html', {'question': question})

---

폼 (form)

• 선택 할 수 있는 형식의 페이지로 변경

# polls/views.py

def vote(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    try:
        selected_choice = question.choice_set.get(pk=request.POST['choice'])
    except (KeyError, Choice,DoesNotExist):
        return render(request, 'polls/detail.html', {'question': question, 'error_message': '
        선택이 없습니다.'})
    else:
        selected_choice.votes +=1
        selected_choice.save()
        retrun HttpResponseRedirect(reverse('polls:index'))
        
# polls/urls.py

from django.urls import path 
from . import views

app_name = 'polls'
urlpatterns = [
    path('', views.index, name='index'), 
    path('<int:question_id>/', views.detail, name='detail'),
    path('<int:question_id>/vote/', views.vote, name='vote'),  
]


# polls/templates/polls/detail.html

<form action="{% url 'polls:vote' question.id %}" method="post">
    {% csrf_token %}
    <h1>{{ question.question_text }}</h1>
    {% if error_message %}
    <p><strong>{{ error_message }}</strong></p>
    {% endif %}
    
    {% for choice in question.choice_set.all %}
        <input type="radio" name="choice" id="choice{{ forloop.counter }}" value="{{ choice.id }}">
        <label for="choice{{ forloop.counter }}">
            {{ choice.choice_text }}
        </label>
        <br>
    {% endfor %}

<input type="submit" value="Vote">
</form>

---

에러 방지하기 (선택하지 않았을 때)

 

# polls/views.py --> 1차

def vote(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    try:
        selected_choice = question.choice_set.get(pk=request.POST['choice'])
    except (KeyError, Choice.DoesNotExist):
        return render(request, 'polls/detail.html', {'question': question, 'error_message': f"선택이 없습니다. id={request.POST['choice']}"})
    else:
        selected_choice.votes += 1
        selected_choice.save()
        return HttpResponseRedirect(reverse('polls:results', args=(question.id,)))
        
# polls/views.py --> 2차

from django.urls import reverse
from django.db.models import F

def vote(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    try:
        selected_choice = question.choice_set.get(pk=request.POST['choice'])
    except (KeyError, Choice.DoesNotExist):
        return render(request, 'polls/detail.html', {'question': question, 'error_message': f"선택이 없습니다. id={request.POST['choice']}"})
    else:
        # A서버에서도 Votes = 1
        # B서버에서도 Votes = 1 
        selected_choice.votes = F('votes') + 1
        selected_choice.save()
        return HttpResponseRedirect(reverse('polls:index'))

---

결과 조회 페이지 수정

 

# polls/views.py

from django.shortcuts import get_object_or_404, render

...
def vote(request, question_id):
...
    else:
        selected_choice.votes = F('votes') + 1
        selected_choice.save()
        return HttpResponseRedirect(reverse('polls:result', args=(question.id,)))

def result(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    return render(request, 'polls/result.html', {'question': question})
    
    
# polls/urls.py

from django.urls import path
from . import views

app_name = 'polls'
urlpatterns = [
    path('', views.index, name='index'),
    path('<int:question_id>/', views.detail, name='detail'),
    path('<int:question_id>/vote/', views.vote, name='vote'),
    path('<int:question_id>/result/', views.result, name='result'),
]


# polls/templates/polls/result.html

<h1>{{ question.question_text }}</h1><br>
{% for choice in question.choice_set.all %}

    <label>
        {{ choice.choice_text }} -- {{ choice.votes }}
    </label>
    <br>
{% endfor %}

---

admin 페이지 수정

 

 

# polls/admin.py

from django.contrib import admin
from .models import Choice, Question

admin.site.register(Choice)

class ChoiceInline(admin.TabularInline):
    model = Choice
    extra = 3


class QuestionAdmin(admin.ModelAdmin):
    fieldsets = [
        ('질문 섹션', {'fields': ['question_text']}),
        ('생성일', {'fields': ['pub_date'], 'classes': ['collapse']}),        
    ]
    readonly_fields = ['pub_date']
    inlines = [ChoiceInline]
    list_filter = ['pub_date']
    search_fields = ['question_text', 'choice__choice_text']
    
admin.site.register(Question, QuestionAdmin)


# polls/models.py

import datetime
from django.db import models
from django.utils import timezone
from django.contrib import admin


class Question(models.Model):
    question_text = models.CharField(max_length=200, verbose='질문')
    pub_date = models.DateTimeField(auto_now_add=True, verbose='생성일')  

    @admin.display(boolean=True, description='최근생성(하루기준)')
    def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)
    
    def __str__(self):
        return f'제목: {self.question_text}, 날짜: {self.pub_date}