TIL - Django

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from .models import *
from django.http import HttpResponse, HttpResponseRedirect #, Http404
from django.shortcuts import render, get_object_or_404
from django.urls import reverse
from django.db.models import F

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# 웹 서버는 요청에 응답하는 역할이기 때문에, 요청을 받고 응답을 반환하는 기능이 필요
def index(request):
    # '-pub_date' : pub_date 기준 "역순"으로
    latest_question_list = Question.objects.order_by("-pub_date")[:5]

    # context = {"{Template 변수(?) 이름}": 값}
    context = {"questions": latest_question_list}
    # request에 대해 context를 넘겨 'polls/index.html' template를 렌더링한다.
    return render(request, "polls/index.html", context)

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def detail(request, question_id):
    """ Http404를 활용하는 방법
    try:
        question = Question.objects.get(pk=question_id)
    except Question.DoesNotExist:
        raise Http404("Question does not exist")
    """
    # Django에서 제공하는 404 Shortcut
    question = get_object_or_404(Question, pk=question_id)
    return render(request, "polls/detail.html", {"question": question})

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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:
        # 동시에 두 서버에서 같은 선택을 한 경우, 값을 제대로 변경하기 위해
        # db에서 값을 읽어 계산 진행
        selected_choice.votes = F("votes") + 1  # F : django db
        selected_choice.save()
    # vote template를 render하지 않고, result page로 redirect
    return HttpResponseRedirect(reverse("polls:result", args=(question_id,)))

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

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{% 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 %} {% comment %} template에서는 인덱싱에 . 사용 questions[0] : X
questions.0 : O appname 설정하지 않은 경우 : url 'detail' appname 설정한 경우 :
url 'polls:detail' '{app_name : name}' in urls.py {% endcomment %}

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<form action={% url 'polls:vote' question.id %} method='post'>
  {# django에서 자동으로 토큰 생성 #}
  {% 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}}">
    <lable for="choice{{ forloop.counter }}">
      {{ choice.choice_text }}
    </lable>
    <br>
  {% endfor %}
  <input type="submit" value="Vote">
</form>

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<h1>{{ question.question_text }}</h1>
<br />
{% for choice in question.choice_set.all %}
<lable> {{ choice.choice_text }} -- {{ choice.votes }} </lable>
<br />
{% endfor %}

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from django.urls import path
from . import views

app_name = "polls" # app_name이 설정된 경우, polls:detail, polls:vote 등 app_name을 필수적으로 포함하여 호출해야 함

urlpatterns = [
    path("", views.index, name="index"),
    # <int:question_id>/ : 사용자가 입력하는 주소를 통해 question_id가 전달됨
    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"),
]

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class Question(models.Model):
    # verbose_name 으로 넘겨준 문자열이 admin page에서 제목으로 표시된다.
    question_text = models.CharField(max_length=200, verbose_name="질문")
    pub_date = models.DateTimeField(auto_now_add=True, verbose_name="생성일")

    # admin page display를 표시하는 방식을 변경한다.
    @admin.display(boolean=True, description="최근생성(하루기준)")
    def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)
    ...

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from django.contrib import admin
from .models import *

# StackedInline, TabularInline
# Question admin page에서 연결된 Choice를 Inline 형태로 출력하기 위한 class
class ChoiceInline(admin.TabularInline):
    model = Choice
    extra = 2  # 추가 등록 칸

# Question admin page customizing
class QuestionAdmin(admin.ModelAdmin):
    fieldsets = [
        ("생성일", {"fields": ["pub_date"], "classes": ["collapse"]}),  # collapse : 숨김처리
        ("질문 섹션", {"fields": ["question_text"]}),
    ]
    list_display = ["question_text", "pub_date", "was_published_recently"]
    readonly_fields = ["pub_date"] # cannot modify.
    inlines = [ChoiceInline]
    list_filter = ["pub_date"]  # filter records by pub_date
    search_fields = ["question_text", "choice__choice_text"]

# register Question to admin site with customized page "QuestionAdmin"
admin.site.register(Question, QuestionAdmin)