examples for flask workshop

00-hello-world.py

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+from flask import Flask
+
+app = Flask(__name__)
+
+
+@app.route('/')
+def hello_world():
+    return 'Hello World!'
+
+
+if __name__ == '__main__':
+    app.run()

01-hello-world-templates.py

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+from flask import Flask, render_template
+app = Flask(__name__)
+
+@app.route('/')
+@app.route('/index')
+def index():
+    user = {'username': 'Simon'}
+    return render_template('index.html', title='Home', user=user)
+
+if __name__ == '__main__':
+    app.run()

02-template-even.py

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+from flask import Flask, render_template
+app = Flask(__name__)
+
+@app.route('/')
+def index():
+    numbers = range(1,25)
+    return render_template('evens.html', title='Evens', numbers=numbers)
+
+if __name__ == '__main__':
+    app.run()

03-template-primes.py

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+from sympy import isprime
+from flask import Flask, render_template
+app = Flask(__name__)
+
+@app.route('/')
+@app.route('/index')
+def index():
+    numbers = range(1,25)
+    return render_template('colorful-primes.html', title='Primes', numbers=numbers, isprime=isprime)
+
+if __name__ == '__main__':
+    app.run()

04-template-inheritance.py

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+from flask import Flask, render_template
+app = Flask(__name__)
+
+@app.route('/')
+def page1():
+    return render_template('page1.html')
+
+if __name__ == '__main__':
+    app.run()

05-input-primes.py

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+from sympy import isprime
+from flask import Flask, render_template
+app = Flask(__name__)
+
+@app.route('/primes')
+@app.route('/primes/<max_number>')
+def primes(max_number=10):
+    numbers = range(1,int(max_number)+1)
+    return render_template('colorful-primes.html', title='Primes', numbers=numbers, isprime=isprime)
+
+if __name__ == '__main__':
+    app.run()

06-input-factorial.py

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+from flask import Flask, render_template
+from functools import reduce
+from operator import mul
+app = Flask(__name__)
+
+@app.route('/factorial/<int:number>')
+def index(number):
+    factorial = reduce(mul, range(1,number+1))
+    return render_template('factorial.html', number=number, factorial=factorial)
+
+if __name__ == '__main__':
+    app.run()

07-input-url.py

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+from flask import Flask, render_template
+app = Flask(__name__)
+
+@app.route('/starter')
+@app.route('/starter/<choice>')
+def starter(choice=None):
+    return render_template('starter.html', choice=choice)
+
+if __name__ == '__main__':
+    app.run()

08-request-handling.py

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+from flask import Flask, render_template, request, redirect, url_for
+app = Flask(__name__)
+
+counter = 0
+
+@app.route('/', methods=('GET', 'POST'))
+def index():
+    global counter
+    if request.method == 'GET':
+        return render_template('request-handling.html', counter=counter)
+    else:
+        if request.form.get('btn') == 'down':
+            counter -= 1
+        elif request.form.get('btn') == 'up':
+                counter += 1
+        return redirect(url_for('index'))
+
+if __name__ == '__main__':
+    app.run()

09-sessions.py

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+from flask import Flask, render_template, request, make_response
+app = Flask(__name__)
+
+@app.route('/', methods=['POST', 'GET'])
+def index():
+    if request.method == 'GET':
+        name = request.cookies.get('name')
+        return render_template('cookies.html', name=name)
+    else:
+        name = request.form['name']
+        resp = make_response(render_template('cookies.html', name=name))
+        resp.set_cookie('name', name)
+        return resp
+
+if __name__ == '__main__':
+    app.run()

10-debugger.py

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+from flask import Flask, render_template
+from flask_debugtoolbar import DebugToolbarExtension
+
+import random
+app = Flask(__name__)
+app.config['SECRET_KEY'] = '<replace with a secret key>'
+app.debug = True
+toolbar = DebugToolbarExtension(app)
+
+@app.route('/')
+def index():
+    coin = random.random()
+    if coin >= 0.5:
+        return render_template('index.html')
+    else:
+        raise Exception("Bad luck")
+
+if __name__ == '__main__':
+    app.run(debug=True)

decorator-example.py

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+from random import random as rnd
+
+def add_lametta(func):
+    def wrapper(*args, **kwargs):
+        return func(*args, **kwargs).replace('+++', '+/+')
+    return wrapper
+
+def add_bulbs(func):
+    def wrapper(*args, **kwargs):
+        return "".join([x if x in ' \n' or rnd() < 0.9 else 'o' for x in func(*args, **kwargs)])
+    return wrapper
+
+def add_stars(func):
+    def wrapper(*args, **kwargs):
+        return "".join([x if x in ' \n' or rnd() < 0.9 else '*' for x in func(*args, **kwargs)])
+    return wrapper
+
+@add_lametta
+@add_bulbs
+def generate_christmas_tree(height):
+    return "\n".join(["".join(['+' if abs(j - (height)/2) < i/2 else ' '
+                               for j in range(height)]) for i in range(height)])
+
+def generate_xmas(height):
+    return "\n".join([' ' * (height - i) + '+' * 2 * i + ' ' * (height - i) for i in range(height)])
+
+print("christmas tree:")
+print(generate_christmas_tree(14))
+
+print(generate_xmas(10))

static/css/style.css

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+body {
+  background-color: #f1f1f1;
+}

templates/colorful-primes.html

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+<html>
+    <head>
+        <title>{{ title }}</title>
+    </head>
+    <body>
+        {% for number in numbers %}
+            {% if isprime(number) %}
+                <b style="color:blue">{{ number }}</b>
+            {% else %}
+                {{ number }}
+            {% endif %}
+        {% endfor %}
+    </body>
+</html>

templates/cookies.html

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+<html>
+   <body>
+   {% if name is none %}
+      <form method = "POST">
+         <p><h3>Enter your name:</h3></p>
+         <p><input type = 'text' name = 'name'/></p>
+         <p><input type = 'submit' value = 'Send'/></p>
+      </form>
+   {% else %}
+    <p><h3>Hello {{ name }}! I will remember you..</h3></p>
+   {% endif %}
+   </body>
+</html>

templates/evens.html

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+<html>
+    <head>
+        <title>{{ title }}</title>
+    </head>
+    <body>
+        {% for number in numbers %}
+            {% if number % 2 == 0 %}
+                <b style="color:limegreen">{{ number }}</b>
+            {% else %}
+                {{ number }}
+            {% endif %}
+        {% endfor %}
+    </body>
+</html>

templates/factorial.html

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+<html>
+    <head>
+        <title>Factorial</title>
+    </head>
+    <body>
+    The factorial of {{ number }} = {{ factorial }}
+    </body>
+</html>

templates/index.html

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+<html>
+    <head>
+        <title>{{ title }}</title>
+    </head>
+    <body>
+        <h1>Hello, {{ user.username }}!</h1>
+    </body>
+</html>

templates/layout.html

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+<!doctype html>
+<html>
+  <head>
+    {% block head %}
+    <link rel="stylesheet" href="{{ url_for('static', filename='style.css') }}">
+    <title>{% block title %}{% endblock %} - My Webpage</title>
+    {% endblock %}
+  </head>
+  <body>
+    <div id="content">{% block content %}{% endblock %}</div>
+    <div id="footer">
+      {% block footer %}
+      &copy; Copyright 2010 by <a href="http://domain.invalid/">you</a>.
+      {% endblock %}
+    </div>
+  </body>
+</html>

templates/page1.html

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+{% extends "layout.html" %}
+{% block title %}Index{% endblock %}
+{% block head %}
+  {{ super() }}
+  <style type="text/css">
+    .important { color: #336699; }
+  </style>
+{% endblock %}
+{% block content %}
+  <h1>Index</h1>
+  <p class="important">
+    Welcome on my awesome homepage.
+{% endblock %}

templates/request-handling.html

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+<html>
+    <head>
+        <title>Counter</title>
+    </head>
+    <body>
+        <h1>Counter =  {{ counter }}</h1>
+    </body>
+    <form method="post">
+        <input type="submit" name="btn" value="up">
+        <input type="submit" name="btn" value="down">
+    </form>
+</html>

templates/starter.html

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+<html>
+    <head>
+        <title>Choose your starter:</title>
+    </head>
+    <body>
+    {% if choice == None  %}
+        Choose your starter:
+        <p><a href="{{ url_for('starter', choice='Bulbasaur') }}">Bulbasaur</a></p>
+        <p><a href="{{ url_for('starter', choice='Charmander') }}">Charmander</a></p>
+        <p><a href="{{ url_for('starter', choice='Squirtle') }}">Squirtle</a></p>
+    {% else %}
+        You chose {{ choice }}!
+    {% endif %}
+    </body>
+</html>