Writing your first Django app--2017年5月9日

Writing your first Django app, part 1

介绍创建项目和app，创建表，更新表，运行，model编写

requriments : Django 1.8 and Python 2.7

创建项目django-admin startproject mysite
.
├── manage.py 命令行呢功能
└── mysite 项目的python包
├── __init__.py 告诉python这个目录是个python包
├── settings.py 配置文件
├── urls.py 支持的url
└── wsgi.py 兼容WSGI的web服务的进入点
更改数据库在settings文件中更改DATABASES
建表python manage.py migrate
创建app python manage.py startapp polls

python manage.py sqlmigrate polls 000
sqlmigrate命令实际上并不在数据库上运行迁移，它只是打印到屏幕上，是用于检查Django要做什么。

如果更改了model，即需要更新表
python manage.py makemigrations ： create migrations for those changes
python manage.py migrate ：apply those changes to the database.

python manage.py shell
manage.py 设置了 DJANGO_SETTINGS_MODULE 环境变量，which gives Django the Python import path to your mysite/settings.py file.

# mysite/polls/models.py
from django.db import models
import datetime
from django.utils import timezone

# Create your models here.

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')

    def __str__(self):
        return self.question_text

    def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)

class Choice(models.Model):
    question = models.ForeignKey(Question)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

    def __str__(self):
        return self.choice_text

Writing your first Django app, part 2

介绍了添加超级用户，自定义管理界面，变更管理界面的外观

Creating an admin user : python manage.py createsuperuser

# mysite/polls/admin.py
from django.contrib import admin
from .models import Choice,Question
# Register your models here.

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

class QuestionAdmin(admin.ModelAdmin):
    #Customize the admin change list  自定义管理界面中的变更列表
    list_display = ('question_text','pub_date','was_published_recently')
    list_filter = ['pub_date']
    search_fields = ['question_text']

    #Customize the admin form  自定义管理表单
    #fields = ['pub_date','question_text']
    fieldsets = [ 
        (None,{'fields':['question_text']}),
        ('Date information',{'fields':['pub_date'],'classes':['collapse']}),
    ]   
    inlines = [ChoiceInline]

#Make the poll app modifiable in the admin  让poll应用在管理站点中可编辑
admin.site.register(Question,QuestionAdmin)
#Adding related objects 添加关联对象
admin.site.register(Choice)

自定义管理站点的外观

将修改主页上的 Django Adminnistration 改为 Polls Administration

在setting.py中将 TEMPLATES的DIRS改为 [os.path.join(BASE_DIR, 'templates')]

先找到配置文件位置，运行如下

$ python -c "
import sys
sys.path = sys.path[1:]
import django
print(django.__path__)"

得到结果 ['/usr/lib64/python2.7/site-packages/django']

在上面的目录下找到 contrib/admin/templates/admin 下 base_site.html 拷贝到工程目录下新建 templates/admin/下  将{{ site_header|default:_('Django administration') }}替换为Polls Administration

Writing your first Django app, part 3

 介绍模板template，url和view

#mysite/mysite/urls.py 
from django.conf.urls import include, url 
from django.contrib import admin

urlpatterns = [ 
    url(r'^admin/', include(admin.site.urls)),
    #带命名空间的URL名字
    url(r'^polls/',include("polls.urls",namespace="polls")),
]

# mysite/polls/urls.py 
from django.conf.urls import url 
from . import views

urlpatterns = [ 
    url(r'^$',views.index,name='index'),
    url(r'^(?P<question_id>[0-9]+)/$',views.detail,name='detail'),
    url(r'^(?P<question_id>[0-9]+)/results/$',views.results,name='results'),
    url(r'^(?P<question_id>[0-9]+)/vote/$',views.vote,name='vote'),
]

# mysite/polls/views.py
from django.shortcuts import render
from django.http import HttpResponse
from .models import Question
#from django.template import loader

# Create your views here.

def index(request):
    print request
    latest_question_list = Question.objects.order_by('-pub_date')[:5]
    #template = loader.get_template('polls/index.html')
    #output = ','.join([p.question_text for p in latest_question_list])
    context = { 
        'latest_question_list': latest_question_list,
    }   
    #return HttpResponse(output)
    #return HttpResponse(template.render(context,request))
    #快捷方式：render()

    return render(request,'polls/index.html',context)

def detail(request,question_id):
    try:
        question = Question.objects.get(pk=question_id)
    except Question.DoesNotExist:
        raise Http404("Question does not exit")
    #return HttpResponse("You`re looking at question %s." % question_id
    return render(request,'polls/detail.html',{'question':question})

def results(request, question_id):
    response = "You`re looking at the results of question %s."
    return HttpResponse(response % question_id)

def vote(request, question_id):
    return HttpResponse("You`re voting on question %s." % question_id)

<!--mysite/polls/templates/polls/index.html-->
{% if latest_question_list %}
    <ul>
    {% for question in latest_question_list %}
        <!--移除模板中硬编码的URLs,带命名空间的URL名字 -->
        <li><a href="{% url 'polls:detail' question.id}">{{question.question_text}}</a></li>
    {% endfor %}
    </ul>
{% else %}
    <p>No polls are available.</p>
{% endif %}

<!--mysite/polls/templates/polls/detail.html-->
<h1>{{question.question_text}}</h1>
<ul>
{% for choice in question.choice_set.all %}
    <li>{{ choice.choice_text }}</li>
{% endfor %}
</ul>

Writing your first Django app, part 4

自定义管理表单