Flask is a small framework, available with a good number of auxiliary functions, suitable for developing
small and medium applications such as:
- Blog
- Forum
- Personal website
- etc.
Our example is a basic web App that has no database yet, just hardcoded items.
pip freeze > requirements.txtblinker==1.6.2
certifi==2023.5.7
charset-normalizer==3.2.0
click==8.1.4
defusedxml==0.7.1
Flask==2.3.2
httpie==3.2.2
idna==3.4
itsdangerous==2.1.2
Jinja2==3.1.2
markdown-it-py==3.0.0
MarkupSafe==2.1.3
mdurl==0.1.2
multidict==6.0.4
Pygments==2.15.1
PySocks==1.7.1
requests==2.31.0
requests-toolbelt==1.0.0
rich==13.4.2
urllib3==2.0.3
Werkzeug==2.3.6from flask import Flask, render_template, request, redirect, url_for, jsonify
app = Flask(__name__)
shopping_list = ['Milk', 'Eggs', 'Potatoes', 'Oranges', 'Bananas']
@app.route('/', methods=['GET', 'POST'])
def index():
global shopping_list
if request.method == 'POST':
shopping_list.append(request.form['item'])
return render_template('index.html', items=shopping_list)
@app.route('/remove/<name>')
def remove_item(name):
global shopping_list
if name in shopping_list:
shopping_list.remove(name)
return redirect(url_for('index'))
@app.route('/api/items')
def get_items():
global shopping_list
return jsonify({'items': shopping_list})
if __name__ == '__main__':
app.run(debug=True)<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Shopping</title>
</head>
<body>
<h1>Shopping Pepe</h1>
<ul>
{% for item in items %}
<li>{{ item }} <a href="{{ url_for('remove_item', name=item) }}">Remove</a> </li>
{% endfor %}
</ul>
<form method="POST">
<input type="text" name="item">
<input type="submit" value="Add to List">
</form>
</body>
</html>If you want to return something else like JSON, then you have to use the jsonify function.
The Flask jsonify() function converts its argument to a JSON string and returns it, along with the HTTP response header indicating that it’s JSON, tha's application/json as the content type in the HTTP header.
Recent versions of Flask will automatically convert it to JSON and return it.
