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91django_基本使用-创新互联

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django.1

django-admin startproject.3

django-admin startapp.5

model:...7

view中使用model:...10

template.11

view中使用template:...13

去掉url和static硬编码:...15

url反解析:...15

url命名空间:...15

form处理:...16

django

是py下一款著名的web框架;

框架,是整个或部分系统的可重用设计,表现为一组抽象构件及构件实例间交互的方法;

是可被应用开发者定制的应用骨架;

其它web框架:flask、tornado;

django优:

自带轮子众多,方便快速开发,如ORM、Auth、Cache、Template、From核心组件;

天生的MVC设计模式;

实用且强大的管理后台;

简洁的url设计;

周边插件丰富;

django缺:

重;

同步阻塞;

django设计哲学:

大而全;

快速开发;

django历史:

最初开发者,Adrian和Simon;

开发背景,World Online维护几个新闻站点,要求快速发布新闻,快速建立其它新闻站点(快速开发、数据驱动);

World Online于05年夏天开源;

https://www.djangoproject.com/

(django) C:\django>pip install django==1.11

(django) C:\django>ipython

In [1]: import django

In [2]: django.get_version()

Out[2]: '1.11'

django version

python versions

1.8

2.7,3.2,3.3,3.4,3.5

1.9,1.10

2.7,3.4,3.5

1.11

2.7,3.4,3.5,3.6

2.0

3.4,3.5,3.6

2.1

3.5,3.6,3.7

响应流程:

91django_基本使用

django-admin startproject

pycharm,New Project-->webproject,C:\webproject

(webproject) C:\webproject>django-admin startproject mysite   #或用python manage.py startproject mysite;此命令脚本在虚拟环境的C:\Users\Administrator\py_env\webproject\Scriptsdjango-admin.exe

91django_基本使用

91django_基本使用

91django_基本使用

mysite/mysite/sessings.py   #项目配置

mysite/mysite/urls.py   #入口url

def url(regex, view, kwargs=None, name=None):   #view是function object,不是函数调用;view函数的第一参数永远是request,不探讨CBV,view函数的返回值永远是HttpResponse对象,显式或隐式;

url(r'^hello/$', hello),   #django默认会给url后加/,此处定义,hello前不带/,hello后一定要有/,这样即使用户访问http://127.0.0.1:8000/hello也会自动跳到http://127.0.0.1:8000/hello/上;若此处配置为r'^hello$',用户访问http://127.0.0.1:8000/hello/,访问的地址无论是否带/都会报404;所以记住,此处定义的url,hello前没有/,hello后要有/;

url(r'^$', views.index, name='index')   #app中的urls.py,可通过name反解出url;

url(r'^polls/', include('polls.urls')),   #项目中的urls.py,include里是str,在用到时才动态导入;

mysite/mysite/wsgi.py   #生产部署时调用

注:

include源码,from django.conf.urls import url, include:

def include(arg, namespace=None, app_name=None):

例:

urls.py

from django.conf.urls import url

from django.contrib import admin

from django.http import HttpResponse

def index(request):

return HttpResponse('this is index')

def hello(request):   #view函数的第一个参数永远是request,不探讨CBV

return HttpResponse('Hello world')

urlpatterns = [   #urlpatterns约定俗成的名字

url(r'^$', index),

url(r'^hello/$', hello),   #django默认会给url后加/,此处定义,hello前不带/,hello后一定要有/,这样即使用户访问http://127.0.0.1:8000/hello也会自动跳到http://127.0.0.1:8000/hello/上;若此处配置为r'^hello$',用户访问http://127.0.0.1:8000/hello/,访问的地址无论是否带/都会报404;所以记住,此处定义的url,hello前没有/,hello后要有/

url(r'^admin/', admin.site.urls),

]

(webproject) C:\webproject\mysite>python manage.py runserver  #可自定义ip:port,python manage.py runserver 0.0.0.0:8080,启动的是django内置webserver,用于测试

91django_基本使用

91django_基本使用

django-admin startapp

django app与django project区别:

app中才能用model;

app设计是可插拔的,app不一定在project中;

settings.py中有内置的app,可根据项目情况禁用;

(webproject) C:\webproject\mysite>django-admin startapp polls   #或用python manage.py startapp polls,新建投票app,在项目根下操作

91django_基本使用

admin.py   #后台管理

apps.py   #1.8ver后加的,app的独立配置

tests.py   #测试用例

views.py   #业务逻辑

migrations/   #与model的版本控制有关

例:

mysite/mysite/settings.py   #在项目settings.py中导入app

INSTALLED_APPS = [

'polls.apps.PollsConfig',

'django.contrib.admin',

'django.contrib.auth',

'django.contrib.contenttypes',

'django.contrib.sessions',

'django.contrib.messages',

'django.contrib.staticfiles',

]

mysite/polls/views.py

from django.shortcuts import render

from django.http import HttpResponse

def index(request):

return HttpResponse('this is index at polls')

mysite/polls/urls.py   #app中的urls.py默认不存在,新建

urlpatterns = [

url(r'^$', views.index, name='index')

]

mysite/mysite/urls.py

urlpatterns = [

url(r'^polls/', include('polls.urls')),   #include中是str,在用到时才动态导入

url(r'^admin/', admin.site.urls),

]

91django_基本使用

model:

支持sqlite、mysql、postgresql、oracle;

py3.5以上版本,不支持MySQLdb驱动;

可用pymysql,py写的;

可用mysqlclient,c写的,速度快,fork的MySQLdb,官方推荐;

ORM,用py的方法、数据结构,来访问db,可兼容不同的DB;

一个class代表一张表,多对多会产生额外一张关系表;

默认pk为id,也可自定义pk;

表名默认为$APP_NAME$CLASS_NAME.lower(),表名小写(跨平台支持),可重写;

models migrations:

定义好models.py需应用到db,django为了能跟踪表结构的变化,增加了migration版本控制功能,如果没有该功能,需手动编写表结构变化的语句,重新导入数据;

models CRUD:

增:

q = Question(**kwargs)   #方式1

q.save()

q = Question.objects.create(**kwargs)   #方式2

删:

q = Question.objects.get(id=1)

q.delete()

Question.objects.filter(id=1).delete()

Question.objects.all().delete()

改:

q = Question.objects.get(id=1)

q.question_text = 'some text'

q.save()

Question.objects.filter(id=1).update(question_text='why ?')

查:

Question.objects.all()

Question.objects.filter(question_text="what's up?")   #objects,model默认的manager管理器

Question.objects.get(id=1)

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

注:

>>> from django.utils import timezone

>>> import datetime

>>> timezone.now()   #比datetime.datetime.now()多了时区,在页面展示时,django内部会转为适合用户所在的时区

datetime.datetime(2019, 1, 2, 7, 2, 18, 244920, tzinfo=)

>>> datetime.datetime.now()

datetime.datetime(2019, 1, 2, 15, 2, 32, 837755)

models中方法:

def __str__(self):

return self.question_text

def was_published_recently(self):

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

mysite/mysite/settings.py

DATABASES = {

'default': {

'ENGINE': 'django.db.backends.sqlite3',

'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),

}

}

mysite/polls/models.py

from django.db import models

class Question(models.Model):   #一个class代表一张表,多对多会产生额外一张关系表;默认pk为id,也可自定义pk;表名默认为$APP_NAME$CLASS_NAME.lower(),可重写

question_text = models.CharField(max_length=200)

pub_date = models.DateTimeField('date published')

class Choice(models.Model):

question = models.ForeignKey(Question, on_delete=models.CASCADE)

choice_text = models.CharField(max_length=200)

votes = models.IntegerField(default=0)

(webproject) C:\webproject\mysite>python manage.py makemigrations   #生成迁移记录

(webproject) C:\webproject\mysite>python manage.py migrate   #应用到db

(webproject) C:\webproject\mysite>sqlite3 db.sqlite3

sqlite> .tables

auth_group                  django_admin_log

auth_group_permissions      django_content_type

auth_permission             django_migrations

auth_user                   django_session

auth_user_groups            polls_choice

auth_user_user_permissions  polls_question

sqlite> .quit

(webproject) C:\webproject\mysite>dir polls\migrations\

驱动器 C 中的卷是 OS

卷的序列号是 000B-5D26

C:\webproject\mysite\polls\migrations 的目录

2019/01/02  14:24   

          .

2019/01/02  14:24   

          ..

2019/01/02  14:24             1,266 0001_initial.py

2019/01/02  11:29                 0 __init__.py

2019/01/02  14:25   

          __pycache__

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 %}

  • {{ person.name }}
  • {% endfor %}

    if:

    {% if max > 10 %}

  • max value is {{ max }}
  • {% else %}

  • max value is 10
  • {% 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 %}

    {% endif %}

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

    91django_基本使用

    去掉url和static硬编码:

    mysite/polls/templates/polls/index.html

    {% load static %}

    {% if latest_question_list %}

    {% 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 %}

    {% csrf_token %}

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


    {% endfor %}

    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

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