Django 信號、中間件、i18n 專題

信號

Django中提供了「信號調度」，用於在框架執行操做時解耦。通俗來說，就是一些動做發生的時候，信號容許特定的發送者去提醒一些接受者。

1. Django內置信號

Model signals
    pre_init                    # django的modal執行其構造方法前，自動觸發
    post_init                   # django的modal執行其構造方法後，自動觸發
    pre_save                    # django的modal對象保存前，自動觸發
    post_save                   # django的modal對象保存後，自動觸發
    pre_delete                  # django的modal對象刪除前，自動觸發
    post_delete                 # django的modal對象刪除後，自動觸發
    m2m_changed                 # django的modal中使用m2m字段操做第三張表（add,remove,clear）先後，自動觸發
    class_prepared              # 程序啓動時，檢測已註冊的app中modal類，對於每個類，自動觸發
Management signals
    pre_migrate                 # 執行migrate命令前，自動觸發
    post_migrate                # 執行migrate命令後，自動觸發
Request/response signals
    request_started             # 請求到來前，自動觸發
    request_finished            # 請求結束後，自動觸發
    got_request_exception       # 請求異常後，自動觸發
Test signals
    setting_changed             # 使用test測試修改配置文件時，自動觸發
    template_rendered           # 使用test測試渲染模板時，自動觸發
Database Wrappers
    connection_created          # 建立數據庫鏈接時，自動觸發

 

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指上述導入的內容

View Code

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

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

View Code

 

2.  自定義信號

a. 定義信號

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

b. 註冊信號

def callback(sender, **kwargs):
    print("callback")
    print(sender,kwargs)
 
pizza_done.connect(callback)

c. 觸發信號

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

於內置信號的觸發者已經集成到Django中，因此其會自動調用，而對於自定義信號則須要開發者在任意位置觸發。

 

Middleware

待續

i18n

待續

 

Django settings

"""
更多信息參考：
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/

# 對稱加密中會用到
SECRET_KEY = ')rt1ka2wqqv%%#!+x9pezqkn!r#!3)+%cee1l4fz$0!s--*!#1'

DEBUG = True           # 開發者模式，生產環境時 DEBUG=False
ALLOWED_HOSTS = ['*']  # 訪問主機，生產環境部署時需設置
APPEND_SLASH = True    # url,自動補齊 /

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

# 中間件配置，有順序
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',  # 自定義全局變量
            ],
        },
    },
]

WSGI_APPLICATION = 'mysite.wsgi.application'

# 設置數據庫
# 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'),
    }
}

# 緩存
CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.db.DatabaseCache',
        'LOCATION': 'my_cache_table',  # 數據庫表
    }
}

# 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


# 郵箱配置
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

# 翻譯文件路徑
LOCALE_PATH = [os.path.join(BASE_DIR, 'locale')]

# 數據庫之類的初始數據
FIXTURE_DIRS = os.path.join(BASE_DIR, 'fixture')

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

# 用戶上傳的靜態文件
MEDIA_ROOT = os.path.join(BASE_DIR, 'mdia')
MEDIA_URL = '/media'

# Auth
LOGIN_URL = '/account/login'   # 設置默認登陸頁面
AUTH_USER_MODEL = 'auth.user'   # 設置用戶驗證的庫表
LOGIN_REDIRECT = '/'             # 若是沒有?next=，登陸後的跳轉網頁
AUTHENTICATION_BACKENDS = ['django.contrib.auth.backends.ModelBackend'] # 如LDAP認證可重寫ModelBacken；依次認證
LOGOUT_REDIRECT_URL = None       # 登陸出，重定向頁面

# Sessions
SESSION_COOKIE_AGE = 1209600
SESSION_COOKIE_DOMAIN = None  # session 只在當前域名下有效
SESSION_COOKIE_NAME = 'sessionid'
SESSION_COOKIE_PATH = '/'     # 全部頁面有效
SESSION_COOKIE_ENGINE = 'django.contib.sessions.backends.db'
SESSION_EXPIRE_AT_BROWSER_CLOSE = False  # 默認瀏覽器關閉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'),
]