Flask-Download-Btn defines a SQLALchemy Mixin for creating Bootstrap download buttons in a Flask application.
Its features include:
- Automatic enabling and disabling. A download button is automatically disabled on click and re-enabled on download completion.
- CSRF protection. The download button checks for a CSRF authentication token to ensure the client has permission to download the requested file.
- Web form handling. Download buttons are responsive to web forms.
- Pre-download operations. Download buttons can easily perform operations before files are downloaded, making it easy to create temporary download files.
- Progress bar. Update your clients on download progress with server sent events.
Installation
$ pip install flask-download-btn
Quickstart
Our folder structure will look like:
templates/
index.html
app.py
In templates/index.html, paste the following Jinja template:
<html>
<head>
<!-- include Bootstrap CSS and Javascript -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css">
<script src="https://code.jquery.com/jquery-3.4.1.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js"></script>
<!-- include download button script -->
{{ download_btn.script() }}
</head>
<body>
<!-- render the download button and progress bar -->
{{ download_btn.btn.render() }}
{{ download_btn.render_progress() }}
</body>
</html>In app.py:
from flask_download_btn import DownloadBtnManager, DownloadBtnMixin
from flask import Flask, render_template, session
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy.ext.orderinglist import ordering_list
app = Flask(__name__)
app.config['SECRET_KEY'] = 'secret'
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///:memory:'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)
# initialize download button manager with application and database
download_btn_manager = DownloadBtnManager(app, db=db)
# create download button model and register it with the manager
@DownloadBtnManager.register
class DownloadBtn(DownloadBtnMixin, db.Model):
id = db.Column(db.Integer, primary_key=True)
# create the database and clear the session when the app starts
@app.before_first_request
def before_first_request():
db.create_all()
session.clear()
HELLO_WORLD_URL = 'https://test-bucket2357.s3.us-east-2.amazonaws.com/hello_world.txt'
# basic use
@app.route('/')
def index():
btn = DownloadBtn()
btn.downloads = [(HELLO_WORLD_URL, 'hello_world.txt')]
db.session.commit()
return render_template('index.html', download_btn=btn)Run the app with:
$ python app.py
And navigate to http://localhost:5000/. Click the download button to download a text file with 'Hello, World!'.
Citation
@software{bowen2020flask-download-btn,
author = {Dillon Bowen},
title = {Flask-Download-Btn},
url = {https://dsbowen.github.io/flask-download-btn/},
date = {2020-06-17},
}
License
Users must cite this package in any publications which use it.
It is licensed with the MIT License.
