Django: a high-level Python Web framework that encourages rapid development and clean, pragmatic design.

On Freenode IRC: #python.tw Speaker: timchen119 (aka. tim/ 使 徒提姆 )

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Linux 使用者協會  http://phorum.study-area.org/  酷 ! 學園  http://www.python.org.tw Python 台灣使 用者群組  http://www.openfoundry.org/  http://whoswho.openfoundry.org/for  OSSF, 自由軟體鑄 造場 ,Who's Who

Web “Framework”? A

web application framework is a set of software tools and libraries to make it easier to create web applications. They typically provide functionality such as database access, templating and session management. -- Wikipedia

• • • • • •

開放原始碼的 Web應用框架。 BSD 自由軟體版權釋出。 Python寫成。 最初是被開發來用於管理勞倫斯出版集團 旗下的一些以新聞內容為主的網站。 命名由來 : 比利時的吉普賽爵士吉他手 Django Reinhardt。 MVC的設計模式。

Django Project's History  January 11, 2006 -- 0.91  July 29, 2006 -- 0.95 ('magic-

removal')  March 23, 2007 -- 0.96 (cleanup and stabilization 0.95)  September 3, 2008 -- 1.0 release.  November 18, 2008 – 1.0.2 release  March 23, 2009 – 1.1 beta  April 2009 -- final 1.1 release (planned)

Popular Web Framework Java: Struts,Spring , WebWork, Tapestry, JSF  PHP:Symfony,CakePHP , Code Igniter, Zend Framework  Perl: Catalyst,Maypole,Jifty  Python:Django,TurboGears ,Pylons,web2py  Ruby: Rails, Nitro,Merb  Lua: Kepler,Orbit 

MVC,MTV 

MVC: Model-View-Controller Architecture MVC Model View Controller



RoR model view controller

Django model template view

MTV: Model-Template-View

HTTP Request

Controller (Django’s View)

View (Django’s Template)

Model

 Only

add complexity when we have strong benefit. (Do not create your own Generic Factory’s Factory’s Factory when you need hammer…)  MVC Decoupling !  Your HTML template separate your model  Your HTML template separate your control logic  Reuse your small logic components

 Great

integration between components  Object-relational mapper (ORM)  Automatic admin interface  Elegant URL design  Template system  Cache system  Internationalization  ……

 Windows  Instant Django  (http://www.instantdjango.com/

)  Notepad++  Python 2.5.2  Sqlite3  Django 1.0  http://kalug.linux.org.tw/~tim/cours (http://tinyurl.com/djangotw)

 Database Wrapper -- model.py  Admin Framework -- admin.py  Controller -- view.py  URL dispatcher -- url.py  Template System -- index.html  settings.py manage.py django-

admin.py are just helper.

• • • • •

下載 Instant Django (django.exe) 至 C:\ – 下載網址 http:// ti nyurl. com/djan go tw 雙擊解壓縮 點擊 start.bat 在提示符號 C:\django> 下打上 django-admin startproject myfirstproject 出現一個 myfirstproject 目錄

 cd

myfirstproject (you could use tab to type less)  dir  manage.py runserver  Ctrl-C to break  Browser: http://127.0.0.1:8000  It worked ! Congratulations on your first Django-powered page.

 python  python

manage.py runserver 80 manage.py runserver 0.0.0.0:80  ipconfig

 myfirstproject/  __init__.py  manage.py  settings.py  urls.py

 __init__.py:

An empty file that tells Python that this directory should be considered a Python package.  manage.py: A command-line utility that lets you interact with this Django project in various ways.

 settings.py:

Settings/configuration for this Django project.  urls.py: The URL declarations for this Django project; a "table of contents" of your Django-powered site.

 本單元目的為熟悉環境之用，並練習修改

urls.py  直接在

Project 底下開發 Helloworld 這個

程式  start.bat  cd c:\django\myfirstproject  notepad++ urls.py

在 urls.py 裡加入一行 (r'^$', 'myfirstproject.helloworldapp.startpage'), 像這樣 : urlpatterns = patterns('', # Example: # (r'^myfirstproject/', include('myfirstproject.foo.urls')), # Uncomment the admin/doc line below and add 'django.contrib.admindocs' # to INSTALLED_APPS to enable admin documentation: # (r'^admin/doc/', include('django.contrib.admindocs.urls')), # Uncomment the next line to enable the admin: # (r'^admin/(.*)', admin.site.root), )

(r'^$', 'myfirstproject.helloworldapp.startpage'),

•

notepad++ helloworldapp.py

from django.http import HttpResponse def startpage(request): return HttpResponse("Hello World!”) • •

manage.py runserver 80 http://127.0.0.1/

HttpResponse(“Hello World!”) 改成 你自己想要印出來的字串。  Reload Browser 。  毋須重啟 server 。  Development Server 的特性。 將

 Django 的強項。  Simple,Clean,Powerful

ORM 。  功能與容易使用程度的平衡性。  透過 model 存取你的關聯性資料庫的資料 。  由 model 自動生成資料庫 WEB 管理介面 。  SQL friendly (but don’t really need to.) 。

 cd c:\django  django-admin startproject  django/mysite/  __init__.py  manage.py  settings.py  urls.py

mysite

 settings.py  DATABASE_ENGINE  DATABASE_NAME :

: sqlite3

C:/django/sqldata.db  always use forward slashes ， Use / not \ even in windows 。  SQLite (do not need to change DATABASE_HOST DATABASE_PASSWORD DATABASE_USER )

 django.contrib.auth

-- An authentication system.  django.contrib.contenttypes -- A framework for content types.  django.contrib.sessions -- A session framework.  django.contrib.sites -- A framework for managing multiple sites with one Django installation.

 python manage.py syncdb  looks at the INSTALLED_APPS

setting and creates any necessary database tables according to the database settings in your settings.py file.  The syncdb command will only create tables for apps in INSTALLED_APPS.

 We just setup "project“  Applications – app  An app is a Web application

that

does something  A project is a collection of configuration and apps for a particular Web site.  A project can contain multiple apps. An app can be in multiple projects.

 python  polls/

manage.py startapp polls

 __init__.py  models.py  views.py

 一個簡單的投票程式

tutorial 裡的範例 )

( 這是 django

 The

first step in writing a database Web app in Django is to define your models  simple poll app  we'll create two models: polls and choices

 Poll:  Question  publication date

 Choices  Poll  Choice  votes

 from django.db import models  class Poll(models.Model):  question

=models.CharField(max_length=200)  pub_date = models.DateTimeField('date published')  class

Choice(models.Model):

 poll = models.ForeignKey(Poll)  choice =

models.CharField(max_length=200)  votes = models.IntegerField()

 INSTALLED_APPS  Add 'mysite.polls‘  python manage.py  python manage.py

sql polls syncdb

 settings.py:  Add "django.contrib.admin" to your

INSTALLED_APPS setting.

 mysite/urls.py

 # Uncomment the next two lines to

enable the admin:  from django.contrib import admin  admin.autodiscover()  # Uncomment the next line to enable the admin: (r'^admin/(.*)', admin.site.root),

 mysite/polls/admin.py  from mysite.polls.models import Poll  from django.contrib import admin  admin.site.register(Poll)

 python manage.py syncdb  Also create a superuser  python manage.py createsuperuser

Django 動手作 單元 4 write

a web announce system  Object-relational mapper (ORM)  Automatic admin interface  Elegant URL design  Designer-friendly Template system

Follow me. #1: Start project  django-admin

startproject webann

webann/ __init__.py manage.py settings.py urls.py

Follow me #2: Create application  cd

webann  python manage.py startapp announce webann/announce/ __init__.py models.py views.py

Follow me #3: Create Database  notepad++

settings.py  DATABASE_ENGINE : sqlite3  DATABASE_NAME :msg.db  INSTALLED_APPS = 'announce'  python manage.py syncdb # also create a superuser

Follow me #4: build your model  webann/announce/models.py

from django.db import models #auto generate class Msg(models.Model): name = models.CharField(max_length=64) date = models.DateTimeField('postdate') msgtxt =

Follow me #5: add admin site  notepad++

webann/announce/admin.py  from webann.announce.models import

Msg  from django.contrib import admin  admin.site.register(Msg)

 settings.py:

 Add "django.contrib.admin" to your

INSTALLED_APPS setting.

 mysite/urls.py

 # Uncomment the next two lines to

Follow me #6: Write Your Template  Edit

TEMPLATE_DIRS in your settings.py  Don’t put template in your www directory.  announcetemplate/announce_list.html #(insert template code here)

Follow me #6: Write Your Template (cont.) {%if msgs_list %} {% for msg in msgs_list %}

{{ msg.name }} at {{msg.date}}

{{msg.msgtxt}}

{% endfor %} {%else %}

No Announce are available now.

{%endif %}

Follow me #7: Write Your View

webann/announce/views.py : from django.shortcuts import render_to_response from superhard.announce.models import Msg def announce_index(request): latest_msg = Msg.objects.all().order_by('date')[:5] return

Follow me #8: urls.py (r'^$', 'announce.views.announce_index'), ('abc', 'announce.views.announce_index'),  urlpatterns = patterns( 'webann.announce.views', (r'^$', 'announce_index'), ('abc', 'announce_index'),  django just need an urlpatterns object

#9: Let’s start play!  python

manage.py runserver  python manage.py syncdb  http://127.0.0.1:8000/  http://127.0.0.1:8000/admin

Deploy  Fastcgi

or mod_python  Static content should be separate  Deploy on web hosting server not as easy as PHP. (for now)  But if it works, it works well !  Lighttpd with fastcgi should be good.

Django 動手作單元 5 Object-Oriented Database Shell

 Playing with the Model's API  python manage.py shell  from mysite.polls.models import

Poll,

Choice  Poll.objects.all()  import datetime  p = Poll(question="What's up?", pub_date=datetime.datetime.now())  p.save()

Playing With Model's API  p.id  p.question  p.pub_date  p.pub_date

= datetime.datetime(2007, 4, 1, 0, 0)  p.save()  Poll.objects.all()

Playing With Model's API import datetime # ... class Poll(models.Model): # ... def was_published_today(self): return self.pub_date.date() == datetime.date.today()

Playing With Model's API class Poll(models.Model): # ... def __unicode__(self): return self.question class Choice(models.Model): # ... def __unicode__(self): return self.choice  Choice.__unicode__ = lambda self: self.choice

Playing With Model's API  Poll.objects.all()  Poll.objects.filter(id=1)  Poll.objects.filter(question__startswith

='What')  Poll.objects.get(pub_date__year=200 7)  Poll.objects.get(id=2)  Poll.objects.get(pk=1)  p = Poll.objects.get(pk=1)  p.was_published_today()

Playing With Model's API  p = Poll.objects.get(pk=1)  p.choice_set.create(choice='Not

much', votes=0)  p.choice_set.create(choice='The sky', votes=0)  c = p.choice_set.create(choice='Just hacking again', votes=0)  c.poll  p.choice_set.all()

Quries → QuerySet (Lazy)  filter  exclude  order_by  distinct  values  ...  QuerySet

→ Lazy

Quries → Not QuerySet  get()  create()  get_or_create()  count()  .....

Django 講解單元 1: Poll from django.conf.urls.defaults import * urlpatterns = patterns('', (r'^polls/$', 'mysite.polls.views.index'), (r'^polls/(?P<poll_id>\d+)/$', 'mysite.polls.views.detail'), (r'^polls/(?P<poll_id>\d+)/results/$', 'mysite.polls.views.results'), (r'^polls/(?P<poll_id>\d+)/vote/$', 'mysite.polls.views.vote'),

Django 講解單元 1: Poll from mysite.polls.models import Poll from django.http import HttpResponse def index(request): latest_poll_list = Poll.objects.all().order_by('-pub_date') [:5] output = ', '.join([p.question for p in latest_poll_list]) return HttpResponse(output)

Django 講解單元 1: Poll from django.template import Context, loader from mysite.polls.models import Poll from django.http import HttpResponse def index(request): latest_poll_list = Poll.objects.all().order_by('-pub_date')[:5] t = loader.get_template('polls/index.html') c = Context({ 'latest_poll_list': latest_poll_list, }) return HttpResponse(t.render(c))

Django 講解單元 1: Poll {% if latest_poll_list %}

{% for poll in latest_poll_list %}
• {{ poll.question }}
{% endfor %}

{% else %}

No polls are available.

{% endif %}

Django 講解單元 1: Poll from django.shortcuts import render_to_response from mysite.polls.models import Poll def index(request): latest_poll_list = Poll.objects.all().order_by('-pub_date') [:5] return render_to_response('polls/index.html',

Django 講解單元 1: Poll from django.http import Http404 # ... def detail(request, poll_id): try: p = Poll.objects.get(pk=poll_id) except Poll.DoesNotExist: raise Http404 return render_to_response('polls/detail.html' , {'poll': p})

Django 講解單元 1: Poll from django.shortcuts import render_to_response, get_object_or_404 # ... def detail(request, poll_id): p = get_object_or_404(Poll, pk=poll_id) return render_to_response('polls/detail.html' , {'poll': p})

Django 講解單元 1: Poll

{{ poll.question }}

{% for choice in poll.choice_set.all %}
• {{ choice.choice }}
{% endfor %}

Django 講解單元 1: Poll urlpatterns = patterns('', (r'^polls/$', 'mysite.polls.views.index'), (r'^polls/(?P<poll_id>\d+)/$', 'mysite.polls.views.detail'), (r'^polls/(?P<poll_id>\d+)/results/$', 'mysite.polls.views.results'), (r'^polls/(?P<poll_id>\d+)/vote/$', 'mysite.polls.views.vote'), )

Django 講解單元 1: Poll urlpatterns = patterns('mysite.polls.views', (r'^polls/$', 'index'), (r'^polls/(?P<poll_id>\d+)/$', 'detail'), (r'^polls/(?P<poll_id>\d+)/results/$', 'results'), (r'^polls/(?P<poll_id>\d+)/vote/$', 'vote'), )

Django 講解單元 1: Poll urlpatterns = patterns('mysite.polls.views', (r'^$', 'index'), (r'^(?P<poll_id>\d+)/$', 'detail'), (r'^(?P<poll_id>\d+)/results/$', 'results'), (r'^(?P<poll_id>\d+)/vote/$', 'vote'), )

Django 講解單元 1: Poll A

simple form

{{ poll.question }}

{% if error_message %}

<strong>{{ error_message }}

{% endif %}

Django 講解單元 1: Poll

{% for choice in poll.choice_set.all %} {{ choice.choice }}
{% endfor %}

Django 講解單元 1: Poll from django.shortcuts import get_object_or_404, render_to_response from django.http import HttpResponseRedirect from django.core.urlresolvers import reverse from mysite.polls.models import Choice, Poll # ...

Django 講解單元 1: Poll def vote(request, poll_id): p = get_object_or_404(Poll, pk=poll_id) try: selected_choice = p.choice_set.get(pk=request.POST['choice' ]) except (KeyError, Choice.DoesNotExist): # Redisplay the poll voting form. return render_to_response('polls/detail.html', { 'poll': p, 'error_message': "You didn't select a

Django 講解單元 1: Poll else: selected_choice.votes += 1 selected_choice.save() # Always return an HttpResponseRedirect after successfully dealing # with POST data. This prevents data from being posted twice if a # user hits the Back button.

return HttpResponseRedirect(reverse('mysit e.polls.views.results', args=(p.id,)))

Django 講解單元 1: Poll def results(request, poll_id): p = get_object_or_404(Poll, pk=poll_id) return render_to_response('polls/results.htm l', {'poll': p})

Django 講解單元 1: Poll

{{ poll.question }}

{% for choice in poll.choice_set.all %}
• {{ choice.choice }} -{{ choice.votes }} vote{{ choice.votes|pluralize }}
{% endfor %}

Django 講解單元 1: Poll from django.conf.urls.defaults import * urlpatterns = patterns('mysite.polls.views', (r'^$', 'index'), (r'^(?P<poll_id>\d+)/$', 'detail'), (r'^(?P<poll_id>\d+)/results/$', 'results'), (r'^(?P<poll_id>\d+)/vote/$', 'vote'), )

Django 講解單元 1: Poll from django.conf.urls.defaults import * from mysite.polls.models import Poll info_dict = { 'queryset': Poll.objects.all(), }

Django 講解單元 1: Poll urlpatterns = patterns('', (r'^$', 'django.views.generic.list_detail.object_list', info_dict), (r'^(?P\d+)/$', 'django.views.generic.list_detail.object_detail', info_dict), url(r'^(?P\d+)/results/$', 'django.views.generic.list_detail.object_detail', dict(info_dict, template_name='polls/results.html'), 'poll_results'), (r'^(?P<poll_id>\d+)/vote/$',

Django Resource 

Django Official Site

 http://www.djangoproject.com/  Official Django Document  http://docs.djangoproject.com/en/1.0/conte  Official Django Tutorial  http://docs.djangoproject.com/en/1.0/intro/  Django Step by Step ( 簡體中文 )  http://www.woodpecker.org.cn/obp/django/  Django Book  http://www.djangobook.com/en/2.0/