一个文件启动Django(基础中的基础)

import sys
from django.conf import settings
#设置
settings.configure(
    DEBUG = True,
    SECRET_KEY = "thisisthesecretkey",
    ROOT_URLCONF=__name__,
    MIDDLEWARE_CLASSES=(
    "django.middleware.common.CommonMiddleware",
    "django.middleware.csrf.CsrfViewMiddleware",
    "django.middleware.clickjacking.XFrameOptionsMiddleware",
    ),
)

from django.conf.urls import url
from django.http import HttpResponse
#视图View
def index(request):
    return HttpResponse("Hello World")
#路由url    
urlpatterns = (
    url(r"^$",index),
)
#相当于简易版manage.py
if __name__=="__main__" :
    from django.core.management import execute_from_command_line
    
    execute_from_command_line(sys.argv)

1.先创建一个py文件,写入上述代码;

2.执行

python hello.py runserver

拓展版:

import os
import sys

from django.conf import settings

DEBUG = OS.environ.get("DEBUG","on") == "on"

SECRET_KEY = os.environ.get("SECRET_KEY",so.urandom(32))

ALLOWED_HOSTS = os.environ.get("ALLOWED_HOSTS","localhost".split(","))

settings.configure(
    DEBUG = DEBUG,
    SECRET_KEY = SECRET_KEY,
    ALLOWED_HOSTS=ALLOWED_HOSTS,
    ROOT_URLCONF=__name__,
    MIDDLEWARE_CLASSES=(
    "django.middleware.common.CommonMiddleware",
    "django.middleware.csrf.CsrfViewMiddleware",
    "django.middleware.clickjacking.XFrameOptionsMiddleware",
    ),
)


from django.conf.urls import url
from django.core.wsgi import get_wsgi_application
from django.http import HttpResponse

def index(request):
    return HttpResponse("Hello World")
    
urlpatterns = (
    url(r"^$",index),
)

application = get_wsgi_application()

if __name__=="__main__" :
        
    from django.core.management import execute_from_command_line
    
    execute_from_command_line(sys.argv)
    

用到知识点

1.wsgi

2.Gunicorn

3.Twelve Factor App

引发问题:

1.一个项目该如何管理开发丶阶段运行和形成产品环境下的不同设置?

模板版:

Django的startproject命令创建的布局可以转换为一个可复用的模板(模板可以是一个目录或ZIP文件)

import os
import sys

from django.conf import settings

DEBUG = os.environ.get("DEBUG","on") == "on"

SECRET_KEY = os.environ.get("SECRET_KEY","{{ secret_key }}")

ALLOWED_HOSTS = os.environ.get("ALLOWED_HOSTS","localhost".split(","))

settings.configure(
    DEBUG = DEBUG,
    SECRET_KEY = SECRET_KEY,
    ALLOWED_HOSTS=ALLOWED_HOSTS,
    ROOT_URLCONF=__name__,
    MIDDLEWARE_CLASSES=(
    "django.middleware.common.CommonMiddleware",
    "django.middleware.csrf.CsrfViewMiddleware",
    "django.middleware.clickjacking.XFrameOptionsMiddleware",
    ),
)


from django.conf.urls import url
from django.core.wsgi import get_wsgi_application
from django.http import HttpResponse

def index(request):
    return HttpResponse("Hello World")
    
urlpatterns = (
    url(r"^$",index),
)

application = get_wsgi_application()

if __name__=="__main__" :
        
    from django.core.management import execute_from_command_line
    
    execute_from_command_line(sys.argv)
    

将文件改名为project_name.py文件放入project_name目录中

执行:django-admin.py startproject foo --template=project_name

神奇的事情发生了,foo的文件夹下会有一个foo.py文件,文件内容和project_name.py一样

什么是无状态?

HTTP本身是一个无状态的协议,意思是每一个到达服务器的请求都独立于之前的请求.如有需要某个特定的状态,则需要把它加到应用层上.例如Cookie.

占位图片服务器

1.用上述的模板创建一个项目名为placeholder

视图层:(分析)

创建两个视图来生成响应

1.按照请求的宽度和高度渲染占位图像

2.渲染主页面的内容,解释项目运作以及生成一些样例图片的方法

路由层:

url会捕获width和height参数并传给视图(数字类型)

表单:

表单用于验证POST和GET内容,也可以用于URL或者Cokkie的值