目錄
django
是py下一款著名的web框架；
框架，是整個或部分系統的可重用設計，表現爲一組抽象構件及構件實例間交互的方法；
是可被應用開發者定製的應用骨架；
其它web框架：flask、tornado；
django優：
自帶輪子衆多，方便快速開發，如ORM、Auth、Cache、Template、From核心組件；
天生的MVC設計模式；
實用且強大的管理後臺；
簡潔的url設計；
周邊插件豐富；
django缺：
重；
同步阻塞；
django設計哲學：
大而全；
快速開發；
django歷史：
最初開發者，Adrian和Simon；
開發背景，World Online維護幾個新聞站點，要求快速發佈新聞，快速建立其它新聞站點（快速開發、數據驅動）；
World Online於05年夏天開源；
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 |
響應流程：
django-admin startproject
pycharm，New Project-->webproject，C:\webproject
(webproject) C:\webproject>django-admin startproject mysite #或用python manage.py startproject mysite；此命令腳本在虛擬環境的C:\Users\Administrator\py_env\webproject\Scriptsdjango-admin.exe
mysite/mysite/sessings.py #項目配置
mysite/mysite/urls.py #入口url
def url(regex, view, kwargs=None, name=None): #view是function object，不是函數調用；view函數的第一參數永遠是request，不探討CBV，view函數的返回值永遠是HttpResponse對象，顯式或隱式；
url(r'^hello/$', hello), #django默認會給url後加/，此處定義，hello前不帶/，hello後一定要有/，這樣即使用戶訪問http://127.0.0.1:8000/hello也會自動跳到http://127.0.0.1:8000/hello/上；若此處配置爲r'^hello$'，用戶訪問http://127.0.0.1:8000/hello/，訪問的地址無論是否帶/都會報404；所以記住，此處定義的url，hello前沒有/，hello後要有/；
url(r'^$', views.index, name='index') #app中的urls.py，可通過name反解出url；
url(r'^polls/', include('polls.urls')), #項目中的urls.py，include裏是str，在用到時才動態導入；
mysite/mysite/wsgi.py #生產部署時調用
注：
include源碼，from django.conf.urls import url, include：
def include(arg, namespace=None, app_name=None):
例：
urls.py
from django.conf.urls import url
from django.contrib import admin
from django.http import HttpResponse
def index(request):
return HttpResponse('this is index')
def hello(request): #view函數的第一個參數永遠是request，不探討CBV
return HttpResponse('Hello world')
urlpatterns = [ #urlpatterns約定俗成的名字
url(r'^$', index),
url(r'^hello/$', hello), #django默認會給url後加/，此處定義，hello前不帶/，hello後一定要有/，這樣即使用戶訪問http://127.0.0.1:8000/hello也會自動跳到http://127.0.0.1:8000/hello/上；若此處配置爲r'^hello$'，用戶訪問http://127.0.0.1:8000/hello/，訪問的地址無論是否帶/都會報404；所以記住，此處定義的url，hello前沒有/，hello後要有/
url(r'^admin/', admin.site.urls),
]
(webproject) C:\webproject\mysite>python manage.py runserver #可自定義ip:port，python manage.py runserver 0.0.0.0:8080，啓動的是django內置webserver，用於測試
django-admin startapp
django app與django project區別：
app中才能用model；
app設計是可插拔的，app不一定在project中；
settings.py中有內置的app，可根據項目情況禁用；
(webproject) C:\webproject\mysite>django-admin startapp polls #或用python manage.py startapp polls，新建投票app，在項目根下操作
admin.py #後臺管理
apps.py #1.8ver後加的，app的獨立配置
tests.py #測試用例
views.py #業務邏輯
migrations/ #與model的版本控制有關
例：
mysite/mysite/settings.py #在項目settings.py中導入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默認不存在，新建
urlpatterns = [
url(r'^$', views.index, name='index')
]
mysite/mysite/urls.py
urlpatterns = [
url(r'^polls/', include('polls.urls')), #include中是str，在用到時才動態導入
url(r'^admin/', admin.site.urls),
]
model：
支持sqlite、mysql、postgresql、oracle；
py3.5以上版本，不支持MySQLdb驅動；
可用pymysql，py寫的；
可用mysqlclient，c寫的，速度快，fork的MySQLdb，官方推薦；
ORM，用py的方法、數據結構，來訪問db，可兼容不同的DB；
一個class代表一張表，多對多會產生額外一張關係表；
默認pk爲id，也可自定義pk；
表名默認爲$APP_NAME$CLASS_NAME.lower()，表名小寫（跨平臺支持），可重寫；
models migrations：
定義好models.py需應用到db，django爲了能跟蹤表結構的變化，增加了migration版本控制功能，如果沒有該功能，需手動編寫表結構變化的語句，重新導入數據；
models CRUD：
增：
q = Question(**kwargs) #方式1
q.save()
q = Question.objects.create(**kwargs) #方式2
刪：
q = Question.objects.get(id=1)
q.delete()
Question.objects.filter(id=1).delete()
Question.objects.all().delete()
改：
q = Question.objects.get(id=1)
q.question_text = 'some text'
q.save()
Question.objects.filter(id=1).update(question_text='why ?')
查：
Question.objects.all()
Question.objects.filter(question_text="what's up?") #objects，model默認的manager管理器
Question.objects.get(id=1)
latest_question_list = Question.objects.order_by('-pub_date')[:3] #默認升序，加上-倒序
注：
>>> from django.utils import timezone
>>> import datetime
>>> timezone.now() #比datetime.datetime.now()多了時區，在頁面展示時，django內部會轉爲適合用戶所在的時區
datetime.datetime(2019, 1, 2, 7, 2, 18, 244920, tzinfo=<UTC>)
>>> datetime.datetime.now()
datetime.datetime(2019, 1, 2, 15, 2, 32, 837755)
models中方法：
def __str__(self):
return self.question_text
def was_published_recently(self):
return self.pub_date >= timezone.now() - datetime.timedelta(days=1)
mysite/mysite/settings.py
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
}
}
mysite/polls/models.py
from django.db import models
class Question(models.Model): #一個class代表一張表，多對多會產生額外一張關係表；默認pk爲id，也可自定義pk；表名默認爲$APP_NAME$CLASS_NAME.lower()，可重寫
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 #生成遷移記錄
(webproject) C:\webproject\mysite>python manage.py migrate #應用到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\
驅動器 C 中的卷是 OS
卷的序列號是 000B-5D26
C:\webproject\mysite\polls\migrations 的目錄
2019/01/02 14:24 <DIR> .
2019/01/02 14:24 <DIR> ..
2019/01/02 14:24 1,266 0001_initial.py
2019/01/02 11:29 0 __init__.py
2019/01/02 14:25 <DIR> __pycache__
2 個文件 1,266 字節
3 個目錄 77,168,365,568 可用字節
(webproject) C:\webproject\mysite>python manage.py sqlmigrate polls 0001_initial #查看sql語句是否是指定要求的
(webproject) C:\webproject\mysite>python manage.py shell #進入交互式命令行
>>> 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=<UTC>)
>>> 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
<Question: fuck you!>
>>> 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] #默認升序，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內置了自己的模板引擎，和jinja很像，使用簡單；
django默認會在app_name/templates/下尋找模板，在app_name/templates/下再建立app_name，這樣app_name/templates/app_name/下存放與該app相關的模板，因爲默認django會去所有的app下找模板，可能會優先找到其它app下的模板；
默認會到app_name/static/下尋找靜態文件；
設置公用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、屬性、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 }}') #變量查找，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'
模板引擎支持循環、判斷、過濾器：
for：
{% for person in person_list %}
<li> {{ person.name }} </li>
{% endfor %}
if：
{% if max > 10 %}
<li>max value is {{ max }} </li>
{% else %}
<li>max value is 10 </li>
{% endif %}
過濾器：
{{ now | date:"F j,Y" }}
{{ name | length }}
view中使用template：
render源碼，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
<img src="/static/django.png"> #mysite/polls/static/django.png
{% if latest_question_list %}
<ul>
{% for question in latest_question_list %}
<li><a href="/polls/{{ question.id }}/">{{ question.question_text }}</a></li>
{% endfor %}
</ul>
{% endif %}
(webproject) C:\webproject\mysite>python manage.py runserver
去掉url和static硬編碼：
mysite/polls/templates/polls/index.html
{% load static %}
<img src="{% static 'django.png' %}">
{% if latest_question_list %}
<ul>
{% for question in latest_question_list %}
<!--<li><a href="/polls/{{ question.id }}/">{{ question.question_text }}</a></li>-->
<li><a href="{% url 'detail' question.id %}">{{ question.question_text }}</a></li>
{% endfor %}
</ul>
{% endif %}
注：
{% url 'detail' question.id %} #app的urls.py中定義的name有關；app namespace改後，'detail'改爲'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()，爲解決循環依賴；
url命名空間：
app namespace和instance namespace：
通常使用app namespace；
若app有多個include，使用instance namespace；
app namespace：
mysite/polls/urls.py #方1，建議使用，在app_name/urls.py中定義
app_name = 'polls'
mysite/mysite/urls.py
url(r'^polls/', include('polls.urls', app_name='polls')), #方2，在項目下定義mysite/mysite/urls.py
instance namespace：
instance級別，名稱不可以重複；
mysite/mysite/urls.py
url(r'^polls/', include('polls.urls', namespace='polls')),
form處理：
mysite/polls/templates/polls/detail.html
<h1>{{ question.question_text }}</h1>
{% if error_message %}
<P><strong>{{ error_message }}</strong></P>
{% endif %}
<form action="{% url 'polls:vote' question.id %}">
{% csrf_token %}
{% for choice in question.choice_set.all %}
<input type="radio" name="choice" id="choice{{ forloop.counter }}" value="{{ choice.id }}" />
<label for="choice{{ forloop.counter }}">{{ choice.choice_text }}</label><br />
{% endfor %}
<input type="submit" value="Vote" />
</form>
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
<h1>{{ question.question_text }}</h1>
<ul>
{% for choice in question.choice_set.all %}
<li>{{ choice.choice_text }} -- {{ choice.votes }} vote{{ choice.votes|pluralize }}</li>
{% endfor %}
</ul>
<a href="{% url 'polls:detail' question.id %}">Vote again?</a>
項目中使用：
pip install pymysql
pip install pillow #ImageField依賴
1、 數據庫使用mysql：
項目目錄的__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目錄下統一放app：
右鍵apps-->Mark directory as-->Source Root #解決編輯器查找，import時可在apps中找
import sys
sys.path.insert(0, os.path.join(BASE_DIR, 'apps')) #解決命令行環境查找