DAY 12

10/31 파이썬 장고 프레임워크를 사용해서 API 서버 만들기(2)

 

1. 뷰(Views) 와 템플릿(Templates)

• poll/views.py

from .models import *
from django.shortcuts import render

def index(request):
    latest_question_list = Question.objects.order_by('-pub_date')[:5]
    context = {'first_question': latest_question_list[0]}
    return render(request, 'polls/index.html', context)

• templates/poll/index.html

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

2. 템플릿에서 제어문 사용하기

• templates/poll/index.html

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

• 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)

3. 상세 페이지 만들기

• poll/views.py

...
def detail(request, question_id):
    question = Question.objects.get(pk=question_id)
    return render(request, 'polls/detail.html', {'question': question})

• poll/urls.py

from django.urls import path
from . import views

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

• templates/poll/detail.html

<h1>{{ question.question_text }}</h1>
<ul>
{% for choice in question.choice_set.all %}
    <li>{{ choice.choice_text }}</li>
{% endfor %}
</ul>

4. 상세 페이지로 링크 추가하기

• poll/urls.py

from django.urls import path 
from . import views  

app_name = 'polls'

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

• templates/poll/index.html

{% if questions %}
<ul>
    {% for question in questions %}
         <li><a href="{% url 'polls:detail' question.id %}">{{ question.question_text }}</a></li>
         
    {% endfor %}
<ul>
{% else %}
<p>no questions</p>
{% endif %}

5. 404 에러 처리하기

• poll/views.py

from models.py import *
from django.http import HttpResponse
from django.http import Http404
from django.shortcuts import render , get_object_or_404

...
def detail(request, question_id):
    """
    try:
        question = Question.objects.get(pk=question_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})

6. 폼(forms)

• poll/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()
        return HttpResponseRedirect(reverse('polls:index'))

 

• poll/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'),  
]

• poll/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>

 

7. 에러 방어하기 1,2

• 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': f"선택이 없습니다. id={request.POST['choice']}"})
    else:
        selected_choice.votes += 1
        selected_choice.save()
        return HttpResponseRedirect(reverse('polls:results', args=(question.id,)))

 

동시에 vote 하는 경우, 서버가 아니라 DB로 연결

• polls/views.py

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'))

 

8. result 조회 페이지

• 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/result.html

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

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

 

• 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'),
]

 

※ args 활용

※  kwargs 활용