Django 信号、中间件、i18n 专题

信号

Django中提供了“信号调度”，用于在框架执行操作时解耦。通俗来讲，就是一些动作发生的时候，信号允许特定的发送者去提醒一些接受者。

1. Django内置信号

Model signals
    pre_init                    # django的modal执行其构造方法前，自动触发
    post_init                   # django的modal执行其构造方法后，自动触发
    pre_save                    # django的modal对象保存前，自动触发
    post_save                   # django的modal对象保存后，自动触发
    pre_delete                  # django的modal对象删除前，自动触发
    post_delete                 # django的modal对象删除后，自动触发
    m2m_changed                 # django的modal中使用m2m字段操作第三张表（add,remove,clear）前后，自动触发
    class_prepared              # 程序启动时，检测已注册的app中modal类，对于每一个类，自动触发
Management signals
    pre_migrate                 # 执行migrate命令前，自动触发
    post_migrate                # 执行migrate命令后，自动触发
Request/response signals
    request_started             # 请求到来前，自动触发
    request_finished            # 请求结束后，自动触发
    got_request_exception       # 请求异常后，自动触发
Test signals
    setting_changed             # 使用test测试修改配置文件时，自动触发
    template_rendered           # 使用test测试渲染模板时，自动触发
Database Wrappers
    connection_created          # 创建数据库连接时，自动触发

from django.core.signals import request_finished
    from django.core.signals import request_started
    from django.core.signals import got_request_exception

    from django.db.models.signals import class_prepared
    from django.db.models.signals import pre_init, post_init
    from django.db.models.signals import pre_save, post_save
    from django.db.models.signals import pre_delete, post_delete
    from django.db.models.signals import m2m_changed
    from django.db.models.signals import pre_migrate, post_migrate

    from django.test.signals import setting_changed
    from django.test.signals import template_rendered

    from django.db.backends.signals import connection_created

    def callback(sender, **kwargs):
        print("xx_callback")
        print(sender,kwargs)

    xx.connect(callback)
    # xx指上述导入的内容

from django.core.signals import request_finished
from django.dispatch import receiver

@receiver(request_finished)
def my_callback(sender, **kwargs):
    print("Request finished!")

2.  自定义信号

a. 定义信号

import django.dispatch
pizza_done = django.dispatch.Signal(providing_args=["toppings", "size"])

b. 注册信号

def callback(sender, **kwargs):
    print("callback")
    print(sender,kwargs)

pizza_done.connect(callback)

c. 触发信号

from 路径 import pizza_done

pizza_done.send(sender='Jonathan',toppings=123, size=456)

于内置信号的触发者已经集成到Django中，所以其会自动调用，而对于自定义信号则需要开发者在任意位置触发。

Middleware

待续

i18n

待续

Django settings

"""
更多信息参考：
https://docs.djangoproject.com/en/1.11/topics/settings/
https://docs.djangoproject.com/en/1.11/ref/settings/
"""
import os
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/1.11/howto/deployment/checklist/

# 对称加密中会用到
SECRET_KEY = ')rt1ka2wqqv%%#!+x9pezqkn!r#!3)+%cee1l4fz$0!s--*!#1'

DEBUG = True           # 开发者模式，生产环境时 DEBUG=False
ALLOWED_HOSTS = ['*']  # 访问主机，生产环境部署时需设置
APPEND_SLASH = True    # url,自动补齐 /

# 实现app可插拔
INSTALLED_APPS = [
    # .......
    'polls',
    'bootstrap3',
]

# 中间件配置，有顺序
MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'mysite.urls'  # 根url

# 前端模板配置
TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        # 'BACKEND': 'django.template.backends.jinja2.Jinja2, # 搜索引擎配置
        'DIRS': [os.path.join(BASE_DIR, 'templates')],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
                'context_processors.global_setting',  # 自定义全局变量
            ],
        },
    },
]

WSGI_APPLICATION = 'mysite.wsgi.application'

# 设置数据库
# https://docs.djangoproject.com/en/1.11/ref/settings/#databases
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
    }
}

# 缓存
CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.db.DatabaseCache',
        'LOCATION': 'my_cache_table',  # 数据库表
    }
}

# Password validation
# https://docs.djangoproject.com/en/1.11/ref/settings/#auth-password-validators
AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]

# Internationalization
# https://docs.djangoproject.com/en/1.11/topics/i18n/
LANGUAGE_CODE = 'en-us'
TIME_ZONE = 'UTC'
USE_I18N = True
USE_L10N = True
USE_TZ = True

# 邮箱配置
EMAIL_HOST = 'smtp.126.com'
EMAIL_PORT = 25
EMAIL_HOST_USER = '******'
EMAIL_HOST_PASSWORD = '******'
# EMAIL_USE_SSL = True # if port is 587, set True
# EMAIL_USE_TLS = True # if port is 465, set True

# 翻译文件路径
LOCALE_PATH = [os.path.join(BASE_DIR, 'locale')]

# 数据库之类的初始数据
FIXTURE_DIRS = os.path.join(BASE_DIR, 'fixture')

# 日志配置
LOGGING = {
    'version':1,
    'handlers':{
        'null':{},
        'console':{},
        'file':{},
        'ansible_logs':{},
    },
}

# 用户上传的静态文件
MEDIA_ROOT = os.path.join(BASE_DIR, 'mdia')
MEDIA_URL = '/media'

# Auth
LOGIN_URL = '/account/login'   # 设置默认登录页面
AUTH_USER_MODEL = 'auth.user'   # 设置用户验证的库表
LOGIN_REDIRECT = '/'             # 如果没有?next=，登录后的跳转网页
AUTHENTICATION_BACKENDS = ['django.contrib.auth.backends.ModelBackend'] # 如LDAP认证可重写ModelBacken；依次认证
LOGOUT_REDIRECT_URL = None       # 登录出，重定向页面

# Sessions
SESSION_COOKIE_AGE = 1209600
SESSION_COOKIE_DOMAIN = None  # session 只在当前域名下有效
SESSION_COOKIE_NAME = 'sessionid'
SESSION_COOKIE_PATH = '/'     # 所有页面有效
SESSION_COOKIE_ENGINE = 'django.contib.sessions.backends.db'
SESSION_EXPIRE_AT_BROWSER_CLOSE = False  # 默认浏览器关闭session不失效

# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/1.11/howto/static-files/
# STATIC_ROOT = r'/www/example/com/staic'
STATIC_URL = '/static/'
STATICFILES_DIRS = [
    os.path.join(BASE_DIR, 'static'),
]