源码分析Django的message组件

# MESSAGE_STORAGE = 'django.contrib.messages.storage.fallback.FallbackStorage'
# MESSAGE_STORAGE = 'django.contrib.messages.storage.cookie.CookieStorage'
MESSAGE_STORAGE = 'django.contrib.messages.storage.session.SessionStorage'

INSTALLED_APPS = [
    # 'django.contrib.admin',
    # 'django.contrib.auth',
    # 'django.contrib.contenttypes',
    # 'django.contrib.sessions',
    'django.contrib.messages',  # 配置
    'django.contrib.staticfiles',
    "web.apps.WebConfig"
]

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',  # 中间件
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
    'utils.md.AuthMiddleware'
]

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [],
        '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',
            ],
        },
    },
]

from django.contrib import messages
messages.add_message(reqeust, messages.SUCCESS, "删除成功1")
messages.add_message(reqeust, messages.ERROR, "操作失败")

from django.contrib.messages.api import get_messages
messages = get_messages(request)
for msg in messages:
    print(msg)

<ul>
    {% for message in messages %}
	    <li>{{ message.tags }} {{ message }}</li>
    {% endfor %}
</ul>

from django.contrib import messages
messages.add_message(reqeust, messages.SUCCESS, "删除成功1")

used = True，则只保存新增部分。
added_new = True，老的数据源加载的+新增的都重新保存到数据源。