Getting Started with Bottle: Installation, HelloWorld, Dynamic Routing, File Download, and POST Handling

Bottle is an ultra‑lightweight Python web framework consisting of a single ~4,000‑line file with no external dependencies, making it easy to install and use.

1. Installing Bottle

Use pip install bottle or download the bottle.py file directly from the GitHub repository (https://github.com/bottlepy/bottle/blob/master/bottle.py).

2. HelloWorld Example

Import get and run from Bottle, define a function decorated with @get('/') that returns a simple string, and start the server with run(host='127.0.0.1', port=80). Execute the script with python HelloWorld.py and visit http://127.0.0.1 in a browser.

3. Static Routing and File Download

Static routes are defined with @get('/'). For serving files, use static_file(filename, root='path/to/files'). The example shows a file store1.txt placed alongside HelloWorld.py, which can be accessed via the browser.

4. Dynamic Routing

Dynamic routes are created with @route('/<name>'), where the placeholder name becomes a function argument. This allows handling variable URLs and serving different content based on the path.

5. POST Requests and File Upload

To handle POST data, import post and request. Use a HTML <form> with method='POST' and enctype='multipart/form-data'. In the handler, retrieve form fields with request.forms.get('field_name') and uploaded files with request.files.get('file_field'), then save the file.

After uploading, the file appears in the server’s directory, confirming a successful POST handling.

6. Running and Deploying

Enable automatic reloading with run(reloader=True) for hot updates. To expose the server beyond localhost, replace the host IP with your public IP (e.g., from ipconfig) and ensure the port (default 80) is open. Then access the site from any device on the network.

Bottle also supports cookies, plugins, multithreading, and can be deployed on various servers, offering many advanced features for further exploration.