Message Flashing

    So here is a full example:

    And here is the template which does the magic:

    1. <!doctype html>
    2. {% with messages = get_flashed_messages() %}
    3.   {% if messages %}
    4.     <ul class=flashes>
    5.     {% for message in messages %}
    6.     {% endfor %}
    7.     </ul>
    8.   {% endif %}
    9. {% endwith %}

    Here is the index.html template which inherits from layout.html:

    And here is the template which also inherits fromlayout.html:

    {% extends "layout.html" %}
{% block body %}
  <h1>Login</h1>
  {% if error %}
    <p class=error><strong>Error:</strong> {{ error }}
  {% endif %}
  <form method=post>
    <dl>
      <dt>Username:
      <dd><input type=text name=username value="{{
          request.form.username }}">
      <dt>Password:
      <dd><input type=password name=password>
    </dl>
    <p><input type=submit value=Login>
  </form>
{% endblock %}

    Changelog

    New in version 0.3.

    It is also possible to provide categories when flashing a message. Thedefault category if nothing is provided is 'message'. Alternativecategories can be used to give the user better feedback. For exampleerror messages could be displayed with a red background.

    To flash a message with a different category, just use the second argumentto the function:

    Inside the template you then have to tell the function to also return thecategories. The loop looks slightly different in that situation then:

    {% with messages = get_flashed_messages(with_categories=true) %}
  {% if messages %}
    <ul class=flashes>
    {% for category, message in messages %}
      <li class="{{ category }}">{{ message }}</li>
    {% endfor %}
    </ul>
  {% endif %}
{% endwith %}

    Changelog

    New in version 0.9.

    Optionally you can pass a list of categories which filters the results of. This is useful if you wish torender each category in a separate block.