django messages

hoge.py

# 参考： http://thinkami.hatenablog.com/entry/2016/02/17/060852

# settings.py
from django.contrib.messages import constants as message_constants
MESSAGE_TAGS = {
    message_constants.ERROR: 'alert alert-danger',
}


# view.py
from django.contrib import messages

...

  # こんな感じで
  messages.error(request, '画像サイズが大きすぎます。最大サイズは 1920x1080[pixel] です。')
  messages.success(request, ...
  messages.warning(request, ...
  messages.debug(request, ...
  messages.info(request, ...


# in template html

  {% if messages %}
      <ul class="messages">
          {% for message in messages %}
              <p {% if message.tags %} class="{{ message.tags }}"{% endif %}>{{ message }}</p>
          {% endfor %}
      </ul>
  {% endif %}