6.1 视图基础

from django.http import HttpResponse
def hello_django_bbs(request):
    html = '<h1>hello django</h1>'
    return HttpResponse(html)

from django.contrib import admin
from django.urls import path
from post import views   # 导入post的views视图函数

urlpatterns = [
    path('admin/', admin.site.urls),
    path('post/hello/',views.hello_django_bbs) # 注册post应用的视图函数
]   

from django.utils.decorators import method_decorator
from django.views import View
from django.views.decorators.csrf import csrf_exempt

class FirstView(View):
    html = '(%s) Hello Django BBS'
    
    def get(self, request):
        return HttpResponse(self.html % 'GET')
    def post(self, request):
        return HttpResponse(self.html % 'POST')
    @method_decorator(csrf_exempt)
    def dispatch(self, request, *args, **kwargs):
        return super(FirstView, self).dispatch(request, *args, **kwargs)

# my_bbs/post/views.py
from django.shortcuts import render
from django.http import HttpResponse
from django.utils.decorators import method_decorator
from django.views import View
from django.views.decorators.csrf import csrf_exempt

class FirstView(View):
    html = '(%s) Hello Django BBS'
    
    def get(self, request):
        return HttpResponse(self.html % 'GET')
    def post(self, request):
        return HttpResponse(self.html % 'POST')
    @method_decorator(csrf_exempt)
    def dispatch(self, request, *args, **kwargs):
        return super(FirstView, self).dispatch(request, *args, **kwargs)

# my_bbs/post/urls.py

from django.urls import path
from post.views import FirstView

urlpatterns = [
    path('hello/',FirstView.as_view()) # 注册post应用的视图函数
]   

# my_bbs/my_bbs/urls.py

from django.contrib import admin
from django.urls import include, path

urlpatterns = [
    path('admin/',admin.site.urls),
    path('post/',include('post.urls'))   # 基于不同APP的urls
]  

class SecondsView(FirstView):
  html = "Seconds ...."

path('second_hello_class/', FirstView.as_view(html="Seconds: (%s) Hello Django Seconds"))

# post/views.py
import time
def exec_time(func):
  def wrapper(*args, **kwargs):
        start = time.time()
        res = func(*args, **kwargs)
        print('%ss elapsed for %s' %(time.time() - start, func.__name__))
        return res
    return wrapper

class ExecTimeMixin(object):
  @method_decorator(csrf_exempt)
  @method_decorator(exec_time)

  def dispatch(self, request, *args, **kwargs):
    return super(ExecTimeMixin, self).dispatch(request, *args, **kwargs)

class FirstView(ExecTimeMixin, View):
  html = '(%s) Hello Django BBS'
  def get(self, request):
      return HttpResponse(self.html % 'GET')
  def post(self, request):
      return HttpResponse(self.html % 'POST')

def dynamic_hello(request, year, month, day):
  html = '<h1>(%s) Hello</h1>'
  return HttpResponse(html % ('%s-%s-%s' % (year, month, day)))

# urls.py
path('dynamic/<int:year>/<int:month>/<int:day>/', views.dynamic_hello)

from django.urls.converters import IntConverter
class MonthConverter(InConverter):
  regex = '0?[1-9]|1[0-2]'

# urls.py
from django.urls import register_converter
from post.views import MonthConverter
register_converter(MonthConverter,'mth')
# 将转换器的类型名设定为mth，之后需要重新定义dynamic_hello视图的urls
path('dymmmic/<int:year>/<mth:month>/<int:day>/', views.dynamic_hello)

# views.py
def dynamic_hello(request, year, month, day=15):
  html = '<h1>(%s) Hello</h1>'
  return HttpResponse(html % ('%s-%s-%s' % (year, month, day)))

# urls.py
path('dymmmic/<int:year>/<mth:month>/', views.dynamic_hello),
path('dymmmic/<int:year>/<mth:month>/<int:day>/', views.dynamic_hello)

import re
r = re.compile('(?P<year>[0-9]{4})')
s = r.search('2022')
print(s.group('year'))
print(s.group(1))

# 2022
# 2022

# urls.py
from django.urls import re_path
re_path('re_dynamic/(?P<year>[0-9]{4})/(?P<month>0[1-9]|1[0-2])/(?P<day>[0-9]{2})', views.dynamic_hello)

# post/post_service.py
def build_comment_info(comment):
    """
    构造Comment信息
    :param comment:
    :return:
    """
    
    return {
        'id': comment.id,
        'content': comment.content,
        'up': comment.up,
        'down': comment.down,
        'created_time': comment.created_time.strftime('%y-%m-%d %H:%M:%S'),
        'last_modified': comment.last_modified.strftime('%y-%m-%d %H:%M:%S'),
    }
from post.models import Comment
def build_topic_detail_info(topic):
    """
    构造Topic详细信息
    :oaram topic:
    :return:
    """
    comment_qs = Comment.objects.filter(topic=topic)
    return {
        "id": topic.id,
        "title": topic.title,
        "content": topic.content,
        "user": topic.user.username,
        "create_time": topic.created_time.strftime('%y-%m-%d %H:%M:%S'),
        'last_modified': topic.last_modified.strftime('%y-%m-%d %H:%M:%S'),
        'comments': [build_comment_info(comment) for comment in comment_qs]
    }

# post/views.py
# comment详细信息
def topic_detail_view(reqeust, topic_id):
    """
    话题详细信息

    :param request:
    :param topic_id:
    :return:
    """
    result = {}
    try:
        result = build_topic_detail_info(Topic.objects.get(pk=topic_id))
    except Topic.DoesNotExist:
        pass
    return JsonResponse(result)

# post/urls.py
urlpatterns = [
  path('topic/<int:topic_id>/',views.topic_detail_view)
]

# post/post_service.py

def add_comment_to_topic(topic,content):
    """
    给话题添加评论

    :param topic:
    :param content:
    :return:
    """
    # 这里简单地根据传递的Topic实例对象和评论内容（content）创建了Comment实例对象。注意，up和down可以使用默认值，不需要指定
    return Comment.objects.create(topic=topic, content=content)

from post.post_service import add_comment_to_topic
def add_comment_to_topic_view(request):
    """
    给话题添加评论

    :param request:
    :return:
    """
    topic_id = int(request.POST.get('id',0))
    content = request.POST.get('content','')
    topic = None
    try:
        topic = Topic.objects.get(pk=topic_id)
    except Topic.DoesNotExist:
        pass
    
    if topic and content:
        return JsonResponse({'id':add_comment_to_topic(topic,content)})
    return JsonResponse({})

urlpatterns = [
    path('topic_comment/', views.add_comment_to_topic_view)
]