91django_基本使用

               2 个文件          1,266 字节

               3 个目录 77,168,365,568 可用字节

(webproject) C:\webproject\mysite>python manage.py sqlmigrate polls 0001_initial   #查看sql语句是否是指定要求的

(webproject) C:\webproject\mysite>python manage.py shell  #进入交互式命令行

>>> from django.utils import timezone

>>> from polls.models import Question,Choice

>>> q = Question(question_text="what's new", pub_date=timezone.now())

>>> q.save()

>>> q.id

1

>>> q.pk

1

>>> q.question_text

"what's new"

>>> q.pub_date

datetime.datetime(2019, 1, 2, 6, 49, 16, 612213, tzinfo=)

>>> from polls.models import Question,Choice

>>> from django.utils import timezone

>>> q = Question.objects.create(question_text="how are you?", pub_date=timezone.now())

>>> q = Question.objects.create(question_text="what's the weather?", pub_date=timezone.now())

>>> q = Question.objects.create(question_text="fuck you!", pub_date=timezone.now())

>>> q

>>> q.was_published_recently()

True

>>> d = timezone.now() - timezone.timedelta(days=2)

>>> q.pub_date = d

>>> q.save()

>>> q.was_published_recently()

False

view中使用model：

from django.http import HttpResponse

from .models import Question

def index(request):

    latest_question_list = Question.objects.order_by('-pub_date')[:3]   #默认升序，加上-倒序

    output = ', '.join([q.question_text for q in latest_question_list])

    return HttpResponse(output)

def detail(request, question_id):

    return HttpResponse('Your are looking at question {}'.format(question_id))

def results(request, question_id):

    response = 'Your are looking at results of question {}'.format(question_id)

    return HttpResponse(response)

def vote(request, question_id):

    return HttpResponse('Your are voting on question {}'.format(question_id))

template

django内置了自己的模板引擎，和jinja很像，使用简单；

django默认会在app_name/templates/下寻找模板，在app_name/templates/下再建立app_name，这样app_name/templates/app_name/下存放与该app相关的模板，因为默认django会去所有的app下找模板，可能会优先找到其它app下的模板；

默认会到app_name/static/下寻找静态文件；

设置公用templates和公用static：

mysite/mysite/settings.py

TEMPLATES = [

    {

        'BACKEND': 'django.template.backends.django.DjangoTemplates',

        'DIRS': [os.path.join(BASE_DIR, 'templates')],

        'APP_DIRS': True,

……

STATIC_URL = '/static/'

STATICFILES_DIRS = [

    os.path.join(BASE_DIR, 'static'),

]

>>> from django.template import Template,Context

>>> t = Template('My name is {{ name }}')

>>> c = Context({'name':'jowin'})   #context可以是 dict、属性、方法、tuple|list

>>> t.render(c)

'My name is jowin'

>>> t = Template('my name is {{ name }}')

>>> d = {'name':'jowin'}

>>> c = Context(d)

>>> t.render(c)

'my name is jowin'

>>> t = Template('my name is {{ user.name }}')   #变量查找，dict、attr、method、list、tuple

>>> class Person:

...     def __init__(self,name):

...             self.name = name

...

>>> user = Person('jowin')

>>> user.name

'jowin'

>>> c = Context({'user':user})

>>> t.render(c)

'my name is jowin'

>>> t = Template('my name is {{ user.name }}')

>>> class Person:

...     def name(self):

...             return 'jowin'

...

>>> user = Person()

>>> user.name()

'jowin'

>>> c = Context({'user':user})

>>> t.render(c)

'my name is jowin'

模板引擎支持循环、判断、过滤器：

for：

{% for person in person_list %}

{% endfor %}

if：

{% if max > 10 %}

{% else %}

{% endif %}

过滤器：

{{ now | date:"F j,Y" }}

{{ name | length }}

view中使用template：

render源码，from django.shortcuts import render：

def render(request, template_name, context=None, content_type=None, status=None, using=None):

    """

    Returns a HttpResponse whose content is filled with the result of calling

    django.template.loader.render_to_string() with the passed arguments.

    """

    content = loader.render_to_string(template_name, context, request, using=using)

    return HttpResponse(content, content_type, status)

另，render_to_response()，老版本1.6用；

mysite/polls/views.py

from django.http import HttpResponse

from .models import Question

from django.template import loader

# def index(request):

#     latest_question_list = Question.objects.order_by('-pub_date')[:4]

#     template = loader.get_template('polls/index.html')

#     context = {'latest_question_list': latest_question_list}

#     # output = ', '.join([q.question_text for q in latest_question_list])

#     return HttpResponse(template.render(context))   #方1

def index(request):

    latest_question_list = Question.objects.order_by('-pub_date')[:4]

    context = {'latest_question_list': latest_question_list}

    return render(request, 'polls/index.html', context)   #方2

mysite/polls/templates/polls/index.html

   #mysite/polls/static/django.png

{% if latest_question_list %}

        {% for question in latest_question_list %}

       

• {{ question.question_text }}

        {% endfor %}

   

{% endif %}

(webproject) C:\webproject\mysite>python manage.py runserver

去掉url和static硬编码：

mysite/polls/templates/polls/index.html

{% load static %}

{% if latest_question_list %}

        {% for question in latest_question_list %}

       

       

• {{ question.question_text }}

        {% endfor %}

   

{% endif %}

注：

{% url 'detail' question.id %}   #app的urls.py中定义的name有关；app namespace改后，'detail'改为'polls:detail'；

url反解析：

正解析，url-->view；

反解析，view-->url；

>>> from django.shortcuts import reverse

>>> reverse('detail',kwargs={'question_id':1})

'/polls/1/'

另，reverse_lazy()，为解决循环依赖；

url命名空间：

app namespace和instance namespace：

通常使用app namespace；

若app有多个include，使用instance namespace；

app namespace：

mysite/polls/urls.py   #方1，建议使用，在app_name/urls.py中定义

app_name = 'polls'

mysite/mysite/urls.py

url(r'^polls/', include('polls.urls', app_name='polls')),   #方2，在项目下定义mysite/mysite/urls.py

instance namespace：

instance级别，名称不可以重复；

mysite/mysite/urls.py

url(r'^polls/', include('polls.urls', namespace='polls')),

form处理：

mysite/polls/templates/polls/detail.html

{{ question.question_text }}

{% if error_message %}

{{ error_message }}

{% endif %}

mysite/polls/views.py

from django.shortcuts import render, get_object_or_404, reverse

from django.http import HttpResponse, HttpResponseRedirect

from .models import Question, Choice

from django.template import loader

# from django.core.urlresolvers import reverse

# def index(request):

#     latest_question_list = Question.objects.order_by('-pub_date')[:4]

#     template = loader.get_template('polls/index.html')

#     context = {'latest_question_list': latest_question_list}

#     # output = ', '.join([q.question_text for q in latest_question_list])

#     return HttpResponse(template.render(context))

def index(request):

    latest_question_list = Question.objects.order_by('-pub_date')[:4]

    context = {'latest_question_list': latest_question_list}

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

def detail(request, question_id):

    # try:

    #     question = Question.objects.get(id=question_id)

    # except Question.DoesNotExist:

    #     return HttpResponse('Not Found', status=404)

    question = get_object_or_404(Question, pk=question_id)

    return render(request, 'polls/detail.html', {'question': question})

def results(request, question_id):

    question = get_object_or_404(Question, pk=question_id)

    return render(request, 'polls/results.html', {'question': question})

def vote(request, question_id):

    question = get_object_or_404(Question, pk=question_id)

    print(request)

    if request.method == 'POST':

        choice_id = request.POST.get('choice', 0)

        try:

            selected_choice = question.choice_set.get(pk=choice_id)

        except Choice.DoesNotExist:

            return render(request, 'polls/detail.html', {

                'question': question, 'error_message': 'You did not select a choice',

            })

        else:

            selected_choice.votes += 1

            selected_choice.save()

            return HttpResponseRedirect(reverse('polls:results', args=(question.id,)))

mysite/polls/templates/polls/results.html

{{ question.question_text }}

    {% for choice in question.choice_set.all %}

   

• {{ choice.choice_text }} -- {{ choice.votes }} vote{{ choice.votes|pluralize }}

    {% endfor %}

Vote again?

项目中使用：

pip install pymysql

pip install pillow   #ImageField依赖

1、 数据库使用mysql：

项目目录的__init__.py中

import pymysql

pymysql.install_as_MySQLdb()

DATABASES = {

  'default': {

      'ENGINE': 'django.db.backends.mysql',

      'NAME': 'mxonline',

      'USER': 'mxonline',

      'PASSWORD': '123456',

      'HOST': '192.168.88.222',

      'PORT': 3306

  }

2、apps目录下统一放app：

右键apps-->Mark directory as-->Source Root   #解决编辑器查找，import时可在apps中找

import sys

sys.path.insert(0, os.path.join(BASE_DIR, 'apps'))   #解决命令行环境查找