mirror of https://github.com/mitsuhiko/flask.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
80 lines
2.3 KiB
80 lines
2.3 KiB
15 years ago
|
Message Flashing
|
||
|
|
================
|
||
|
|
|
||
|
|
Good applications and user interfaces are all about feedback. If the user
|
||
|
|
does not get enough feedback he will probably end up hating the
|
||
|
|
application. Flask provides a really simple way to give feedback to a
|
||
|
|
user with the flashing system. The flashing system basically makes it
|
||
|
|
possible to record a message at the end of a request and access it next
|
||
|
|
request and only next request. This is usually combined with a layout
|
||
|
|
template that does this.
|
||
|
|
|
||
|
|
So here a full example::
|
||
|
|
|
||
|
|
from flask import flash, redirect, url_for, render_template
|
||
|
|
|
||
|
|
@app.route('/')
|
||
|
|
def index():
|
||
|
|
return render_template('index.html')
|
||
|
|
|
||
|
|
@app.route('/login', methods=['GET', 'POST'])
|
||
|
|
def login():
|
||
|
|
error = None
|
||
|
|
if request.method == 'POST':
|
||
|
|
if request.form['username'] != 'admin' or \
|
||
|
|
request.form['password'] != 'secret':
|
||
|
|
error = 'Invalid credentials'
|
||
|
|
else:
|
||
|
|
flash('You were sucessfully logged in')
|
||
|
|
return redirect(url_for('index'))
|
||
|
|
return render_template('login.html', error=error)
|
||
|
|
|
||
|
|
And here the ``layout.html`` template which does the magic:
|
||
|
|
|
||
|
|
.. sourcecode:: html+jinja
|
||
|
|
|
||
|
|
<!doctype html>
|
||
|
|
<title>My Application</title>
|
||
|
|
{% with messages = get_flashed_messages() %}
|
||
|
|
{% if messages %}
|
||
|
|
<ul class=flashes>
|
||
|
|
{% for message in messages %}
|
||
|
|
<li>{{ message }}</li>
|
||
|
|
{% endfor %}
|
||
|
|
</ul>
|
||
|
|
{% endif %}
|
||
|
|
{% endwith %}
|
||
|
|
{% block body %}{% endblock %}
|
||
|
|
|
||
|
|
And here the index.html template:
|
||
|
|
|
||
|
|
.. sourcecode:: html+jinja
|
||
|
|
|
||
|
|
{% extends "layout.html" %}
|
||
|
|
{% block body %}
|
||
|
|
<h1>Overview</h1>
|
||
|
|
<p>Do you want to <a href="{{ url_for('login') }}">log in?</a>
|
||
|
|
{% endblock %}
|
||
|
|
|
||
|
|
And of course the login template:
|
||
|
|
|
||
|
|
.. sourcecode:: html+jinja
|
||
|
|
|
||
|
|
{% extends "layout.html" %}
|
||
|
|
{% block body %}
|
||
|
|
<h1>Login</h1>
|
||
|
|
{% if error %}
|
||
|
|
<p class=error><strong>Error:</strong> {{ error }}
|
||
|
|
{% endif %}
|
||
|
|
<form action="" 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 %}
|