# Flask-Fingerprint
[](https://codeberg.org/S1SYPHOS/flask-fingerprint/src/branch/main/LICENSE) [](https://pypi.org/project/flask-fingerprint) [](https://codeberg.org/S1SYPHOS/flask-fingerprint/issues)
This project is a lightweight [`Flask`](https://flask.palletsprojects.com) extension for cache-busting static assets via file hash or query parameter.
## Installation
It's available from [PyPi](https://pypi.org/project/flask-fingerprint) using `pip`:
```text
pip install Flask-Fingerprint
```
## Getting started
Using this library is straightforward:
```python
from flask_fingerprint import Fingerprint
# Configuration
config = {
'manifest': 'path/to/manifest.json',
'extensions': ['js', 'css', 'jpg'],
'hash_size': 12,
'query': False,
}
# Option 1
Fingerprint(app, config)
# Option 2
ext = Fingerprint(config=config)
ext.init_app(app)
```
After that, [`url_for`](https://flask.palletsprojects.com/en/latest/api/#flask.Flask.url_for) takes care of cache-busting your static assets auto-magically:
```html
<!-- When enabled, this .. -->
<script src="{{ url_for('static', filename='js/main.js') }}"></script>
<!-- .. becomes this .. -->
<script src="/<static-folder>/js/main.f1l3h4sh.js"></script>
```
Unless passing a manifest file (as created by third-party tools like [`gulp-rev`](https://github.com/sindresorhus/gulp-rev)) or using `query` mode (see section 'Configuration'), you need to implement server rules to make this work.
### Apache
Place the following snippet inside your `.htaccess`, right after `RewriteBase`:
```text
# RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.+)\.([0-9a-z]{8})\.(js|css)$ $1.$3 [L]
```
**Note**: The `{8}` part has to match your `hash_size` (see section 'Configuration').
### NGINX
Place the following snippet anywhere inside your virtual host setup:
```text
location ~ (.+)\.(?:\w+)\.(js|css)$ {
try_files $uri $1.$2;
}
```
## Usage
### `__init__(app: Flask = None, config: dict = None)`
Creates `Fingerprint` instance.
### `init_app(app: Flask, config: dict)`
See `__init__` above.
**Note**: `flask_fingerprint` also exposes a `logger` instance which might prove useful when debugging!
## Configuration
When passing a `config` object (like in the example above), you may use the following options:
### `manifest: str`:
Manifest file, mapping unbusted filenames & their busted revisions. Default: `<static_folder>/manifest.json`
### `extensions: list | str`:
Allowed extensions. Default: `['css', 'js']`
### `hash_size: int`:
Length of file hash. Default: `8`
### `query: bool`:
Use query parameter instead of file hash. Default: `False`
## Credits
This extension was [inspired](https://github.com/ChrisTM/Flask-CacheBust) [by](https://github.com/daxlab/Flask-Cache-Buster) [other](https://github.com/israel-fl/Flask-CacheBust) [solutions](https://github.com/raicheff/flask-rev) for cache-busting assets in Flask applications.
