Added mini blogging application as Flask example.

This should become the tutorial.

examples/flaskr/flaskr.py

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+# -*- coding: utf-8 -*-
+"""
+    Flaskr
+    ~~~~~~
+
+    A microblog example application written as Flask tutorial with
+    Flask and sqlite3.
+
+    :copyright: (c) 2010 by Armin Ronacher.
+    :license: BSD, see LICENSE for more details.
+"""
+from __future__ import with_statement
+import time
+import sqlite3
+from contextlib import closing
+from flask import Flask, request, session, g, redirect, url_for, abort, \
+     render_template, flash
+from werkzeug import secure_filename
+
+# configuration
+DATABASE = '/tmp/flaskr.db'
+DEBUG = True
+SECRET_KEY = 'development key'
+USERNAME = 'admin'
+PASSWORD = 'default'
+
+# create our little application :)
+app = Flask(__name__)
+app.secret_key = SECRET_KEY
+app.debug = DEBUG
+
+
+def connect_db():
+    """Returns a new connection to the database."""
+    return sqlite3.connect(DATABASE)
+
+
+def init_db():
+    """Creates the database tables."""
+    with closing(connect_db()) as db:
+        with app.open_resource('schema.sql') as f:
+            db.cursor().executescript(f.read())
+        db.commit()
+
+
+@app.request_init
+def before_request():
+    """Make sure we are connected to the database each request.  Also
+    set `g.logged_in` to `True` if we are logged in.
+    """
+    g.db = connect_db()
+    g.logged_in = session.get('logged_in', False)
+
+
+@app.request_shutdown
+def after_request(response):
+    """Closes the database again at the end of the request."""
+    g.db.close()
+    return response
+
+
+@app.route('/')
+def show_entries():
+    cur = g.db.execute('select title, text from entries order by id desc')
+    entries = [dict(title=row[0], text=row[1]) for row in cur.fetchall()]
+    return render_template('show_entries.html', entries=entries)
+
+
+@app.route('/add', methods=['POST'])
+def add_entry():
+    if not g.logged_in:
+        abort(401)
+    g.db.execute('insert into entries (title, text) values (?, ?)',
+                 [request.form['title'], request.form['text']])
+    g.db.commit()
+    flash('New entry was successfully posted')
+    return redirect(url_for('show_entries'))
+
+
+@app.route('/login', methods=['GET', 'POST'])
+def login():
+    error = None
+    if request.method == 'POST':
+        if request.form['username'] != USERNAME:
+            error = 'Invalid username'
+        elif request.form['password'] != PASSWORD:
+            error = 'Invalid password'
+        else:
+            session['logged_in'] = True
+            flash('You were logged in')
+            return redirect(url_for('show_entries'))
+    return render_template('login.html', error=error)
+
+
+@app.route('/logout')
+def logout():
+    session.pop('logged_in', None)
+    flash('You were logged out')
+    return redirect(url_for('show_entries'))
+
+
+if __name__ == '__main__':
+    app.run()

examples/flaskr/flaskr_tests.py

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+# -*- coding: utf-8 -*-
+"""
+    Flaskr Tests
+    ~~~~~~~~~~~~
+
+    Tests the Flaskr application.
+
+    :copyright: (c) 2010 by Armin Ronacher.
+    :license: BSD, see LICENSE for more details.
+"""
+import flaskr
+import unittest
+import tempfile
+
+
+class FlaskrTestCase(unittest.TestCase):
+
+    def setUp(self):
+        """Before each test, set up a blank database"""
+        self.db = tempfile.NamedTemporaryFile()
+        self.app = flaskr.app.test_client()
+        flaskr.DATABASE = self.db.name
+        flaskr.init_db()
+
+    def login(self, username, password):
+        return self.app.post('/login', data=dict(
+            username=username,
+            password=password
+        ), follow_redirects=True)
+
+    def logout(self):
+        return self.app.get('/logout', follow_redirects=True)
+
+    # testing functions
+
+    def test_login_logout(self):
+        """Make sure login and logout works"""
+        rv = self.login(flaskr.USERNAME, flaskr.PASSWORD)
+        assert 'You were logged in' in rv.data
+        rv = self.logout()
+        assert 'You were logged out' in rv.data
+        rv = self.login(flaskr.USERNAME + 'x', flaskr.PASSWORD)
+        assert 'Invalid username' in rv.data
+        rv = self.login(flaskr.USERNAME, flaskr.PASSWORD + 'x')
+        assert 'Invalid password' in rv.data
+
+    def test_messages(self):
+        """Test that messages work"""
+        # start with a blank state
+        rv = self.app.get('/')
+        assert 'No entries here so far' in rv.data
+        self.login(flaskr.USERNAME, flaskr.PASSWORD)
+        rv = self.app.post('/add', data=dict(
+            title='<Hello>',
+            text='<strong>HTML</strong> allowed here'
+        ), follow_redirects=True)
+        assert 'No entries here so far' not in rv.data
+        self.login(flaskr.USERNAME, flaskr.PASSWORD)
+        assert '&lt;Hello&gt' in rv.data
+        assert '<strong>HTML</strong> allowed here' in rv.data
+
+
+if __name__ == '__main__':
+    unittest.main()

examples/flaskr/schema.sql

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+drop table if exists entries;
+create table entries (
+  id integer primary key autoincrement,
+  title string not null,
+  text string not null
+);

examples/flaskr/static/style.css

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+body { font-family: sans-serif; background: #eee; }
+a, h1, h2 { color: #377BA8; }
+h1, h2 { font-family: 'Georgia', serif; margin: 0; }
+h1 { border-bottom: 2px solid #eee; }
+h2 { font-size: 1.2em; }
+div.metanav { text-align: right; font-size: 0.8em; background: #fafafa;
+              padding: 0.3em; margin-bottom: 1em; }
+ul.entries { list-style: none; margin: 0; padding: 0; }
+ul.entries li { margin: 0.8em 1.2em; }
+ul.entries li h2 { margin-left: -1em; }
+div.page { margin: 2em auto; width: 35em; border: 5px solid #ccc;
+           padding: 0.8em; background: white; }
+form.add-entry { font-size: 0.9em; border-bottom: 1px solid #ccc; }
+form.add-entry dl { font-weight: bold; }
+div.flash { background: #CEE5F5; padding: 0.5em; border: 1px solid #AACBE2; }
+p.error { background: #F0D6D6; padding: 0.5em; }

examples/flaskr/templates/layout.html

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+<!doctype html>
+<title>Flaskr</title>
+<link rel=stylesheet type=text/css href="{{ url_for('static', filename='style.css') }}">
+<div class=page>
+  <h1>Flaskr</h1>
+  <div class=metanav>
+  {% if not g.logged_in %}
+    <a href="{{ url_for('login') }}">log in</a>
+  {% else %}
+    <a href="{{ url_for('logout') }}">log out</a>
+  {% endif %}
+  </div>
+  {% for message in get_flashed_messages() %}
+    <div class=flash>{{ message }}</div>
+  {% endfor %}
+  {% block body %}{% endblock %}
+</div>

examples/flaskr/templates/login.html

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+{% extends "layout.html" %}
+{% block body %}
+  <h2>Login</h2>
+  {% if error %}<p class=error><strong>Error:</strong> {{ error }}{% endif %}
+  <form action="{{ url_for('login') }}" method=post>
+    <dl>
+      <dt>Username:
+      <dd><input type=text name=username>
+      <dt>Password:
+      <dd><input type=passowrd name=password>
+      <dd><input type=submit value=Login>
+    </dl>
+  </form>
+{% endblock %}

examples/flaskr/templates/show_entries.html

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+{% extends "layout.html" %}
+{% block body %}
+  {% if g.logged_in %}
+    <form action="{{ url_for('add_entry') }}" method=post class=add-entry>
+      <dl>
+        <dt>Title:
+        <dd><input type=text size=30 name=title>
+        <dt>Text:
+        <dd><textarea name=text rows=5 cols=40></textarea>
+        <dd><input type=submit value=Share>
+      </dl>
+    </form>
+  {% endif %}
+  <ul class=entries>
+  {% for entry in entries %}
+    <li><h2>{{ entry.title }}</h2>{{ entry.text|safe }}
+  {% else %}
+    <li><em>Unbelievable.  No entries here so far</em>
+  {% endfor %}
+  </ul>
+{% endblock %}