django之旅 1.hello world

　　一但你安装好了python，django和（可选的）数据库及相关库，你就可以通过创建一个project，迈出开发django应用的第一步。

项目 是 Django 实例的一系列设置的集合，它包括数据库配置、Django 特定选项以及应用程序的特定设置。

　　django采用的是MTV模式，即Models、Temples、Views三层，类似.net的MVC模式

　　首先创建一个django项目，在上一篇django安装配置中有说明，然后加载进wingide中。

　　该项目下包含4个文件：

mysite/
    mysite/
        __init__.py
        wsgi.py
        settings.py
         urls.py
    manage.py

文件如下：

• __init__.py ：让 Python 把该目录当成一个开发包 (即一组模块)所需的文件。 这是一个空文件，一般你不需要修改它。

• manage.py ：一种命令行工具，允许你以多种方式与该 Django 项目进行交互。 键入python manage.py help，看一下它能做什么。 你应当不需要编辑这个文件；在这个目录下生成它纯是为了方便

• settings.py ：该 Django 项目的设置或配置。 查看并理解这个文件中可用的设置类型及其默认值。

• urls.py：Django项目的URL设置。 可视其为你的django网站的目录。

　　尽管这些的文件很小，但这些文件已经构成了一个可运行的Django应用。

　　创建好这些后就开始配置项目，首先我们开始配置setting.py

# Django settings for eshop project.

DEBUG = True
TEMPLATE_DEBUG = DEBUG

　　这个是设置是否编译调试程序

ADMINS = (
    # ('Your Name', 'your_email@example.com'),
)

MANAGERS = ADMINS

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3', # Add 'postgresql_psycopg2', 'mysql', 'sqlite3' or 'oracle'.
        'NAME': './data.db',                      # Or path to database file if using sqlite3.
        # The following settings are not used with sqlite3:
        'USER': '',
        'PASSWORD': '',
        'HOST': '',                      # Empty for localhost through domain sockets or '127.0.0.1' for localhost through TCP.
        'PORT': '',                      # Set to empty string for default.
    }
}

# Hosts/domain names that are valid for this site; required if DEBUG is False
# See https://docs.djangoproject.com/en/1.5/ref/settings/#allowed-hosts
ALLOWED_HOSTS = []

# Local time zone for this installation. Choices can be found here:
# http://en.wikipedia.org/wiki/List_of_tz_zones_by_name
# although not all choices may be available on all operating systems.
# In a Windows environment this must be set to your system time zone.
TIME_ZONE = 'America/Chicago'

# Language code for this installation. All choices can be found here:
# http://www.i18nguy.com/unicode/language-identifiers.html
LANGUAGE_CODE = 'zh-cn'

SITE_ID = 1

# If you set this to False, Django will make some optimizations so as not
# to load the internationalization machinery.
USE_I18N = True

# If you set this to False, Django will not format dates, numbers and
# calendars according to the current locale.
USE_L10N = True

# If you set this to False, Django will not use timezone-aware datetimes.
USE_TZ = True

# Absolute filesystem path to the directory that will hold user-uploaded files.
# Example: "/var/www/example.com/media/"
MEDIA_ROOT = './media'

# URL that handles the media served from MEDIA_ROOT. Make sure to use a
# trailing slash.
# Examples: "http://example.com/media/", "http://media.example.com/"
MEDIA_URL = '/media/'

# Absolute path to the directory static files should be collected to.
# Don't put anything in this directory yourself; store your static files
# in apps' "static/" subdirectories and in STATICFILES_DIRS.
# Example: "/var/www/example.com/static/"
STATIC_ROOT = './static'

# URL prefix for static files.
# Example: "http://example.com/static/", "http://static.example.com/"
STATIC_URL = '/static/'

# Additional locations of static files
STATICFILES_DIRS = (
    # Put strings here, like "/home/html/static" or "C:/www/django/static".
    # Always use forward slashes, even on Windows.
    # Don't forget to use absolute paths, not relative paths.
)

# List of finder classes that know how to find static files in
# various locations.
STATICFILES_FINDERS = (
    'django.contrib.staticfiles.finders.FileSystemFinder',
    'django.contrib.staticfiles.finders.AppDirectoriesFinder',
#    'django.contrib.staticfiles.finders.DefaultStorageFinder',
)

# Make this unique, and don't share it with anybody.
SECRET_KEY = 's(t*k5l+dof0m28bd13%jc%z=6p$p8mjf=#mq9d4*94+7@@l+u'

# List of callables that know how to import templates from various sources.
TEMPLATE_LOADERS = (
    'django.template.loaders.filesystem.Loader',
    'django.template.loaders.app_directories.Loader',
#     'django.template.loaders.eggs.Loader',
)

MIDDLEWARE_CLASSES = (
    'django.middleware.common.CommonMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    # Uncomment the next line for simple clickjacking protection:
    # 'django.middleware.clickjacking.XFrameOptionsMiddleware',
)

ROOT_URLCONF = 'eshop.urls'

# Python dotted path to the WSGI application used by Django's runserver.
WSGI_APPLICATION = 'eshop.wsgi.application'

TEMPLATE_DIRS = (
    # Put strings here, like "/home/html/django_templates" or "C:/www/django/templates".
    # Always use forward slashes, even on Windows.
    # Don't forget to use absolute paths, not relative paths.
    './templ'
)

  INSTALLED_APPS = (
  　　'django.contrib.auth',
  　　'django.contrib.contenttypes',
  　　'django.contrib.sessions',
  　　'django.contrib.sites',
  　　'django.contrib.messages',
  　　'django.contrib.staticfiles',
 　　 # Uncomment the next line to enable the admin:
 　　 'django.contrib.admin',
 　　 # Uncomment the next line to enable admin documentation:
 　　 # 'django.contrib.admindocs',
  　　'order'
 )

DATABASES 配置后台使用的数据库，

LANGUAGE_CODE表示语种，

MEDIA_ROOT为媒体文件存放路径,

SECRET_KEY为加密密钥，

ROOT_URLCONF为url.py存放路径，

INSTALLED_APPS 为App目录，

TEMPLATE_DIRS为Temples的目录

配置完setting后，接着配置urls

from django.conf.urls import patterns, include, url

# Uncomment the next two lines to enable the admin:
from django.contrib import admin
admin.autodiscover()

urlpatterns = patterns('',
    # Examples:
     url(r'^$', 'order.views.index', name='home'),
    # url(r'^eshop/', include('eshop.foo.urls')),

    # Uncomment the admin/doc line below to enable admin documentation:
    # url(r'^admin/doc/', include('django.contrib.admindocs.urls')),

    # Uncomment the next line to enable the admin:
    url(r'^admin/', include(admin.site.urls)),
)

这里需要将注销的url(r'^$', 'order.views.index', name='home')还原，这条语句是调用order这个应用中的views.py文件中的index方法，views.py内容如下

# Create your views here.
from django.http import HttpResponse

#----------------------------------------------------------------------
def index(request):
    """"""
    return HttpResponse("hello python")

如果要启用admin的话还需要将下面这三条语句前的注释符号去掉

from django.contrib import admin
admin.autodiscover()
url(r'^admin/', include(admin.site.urls))

创建完项目后，还需要创建app ，在进入创建的项目的目录输入“python manage.py startapp order”,order为app名称，即在根目录下会创建一个order文件夹。

该文件夹下面同样包含四个文件

order/
    models.py
    tests.py
    views.py
    __init__.py

models,views,__init__文件都为空，这个就是MTV中的M和V

models是创建数据库表

from django.db import models

# Create your models here.
class Product(models.Model):
    name = models.CharField("product_name",max_length=30)
    

views代码已经在上文中贴出。

另外我们还需要在order目录下添加一个admin.py文件，该文件的作用是管理models

from django.contrib import admin

from models import Product

admin.site.register(Product)

product为model，如果有多个model，则表述方法为from models import  <model1,model2>，另外需要将每个model注册一次  amin.site.register(model1)

到这里差不多弄完了，最后一步是生成数据库，进入项目根目录，输入“python manage.py syncdb”命令，然后按照提示输入数据库账号、密码等信息。

最后将manage.py设置为主运行文件，运行时设置Run Arguments为runserver 127.0.0.1:8000,然后我们可以通过浏览器访问“127.0.0.1:8000”进入数据后台管理中心。