Files
notifications-admin/app/asset_fingerprinter.py

51 lines
1.6 KiB
Python

import hashlib
class AssetFingerprinter(object):
"""
Get a unique hash for an asset file, so that it doesn't stay cached
when it changes
Usage:
in the application
template_data.asset_fingerprinter = AssetFingerprinter()
where template data is how you pass variables to every template.
in template.html:
{{ asset_fingerprinter.get_url('stylesheets/application.css') }}
* 'app/static' is assumed to be the root for all asset files
"""
def __init__(self, asset_root="/static/", filesystem_path="app/static/"):
self._cache = {}
self._asset_root = asset_root
self._filesystem_path = filesystem_path
def get_url(self, asset_path, with_querystring_hash=True):
if not with_querystring_hash:
return self._asset_root + asset_path
if asset_path not in self._cache:
self._cache[asset_path] = (
self._asset_root
+ asset_path
+ "?"
+ self.get_asset_fingerprint(self._filesystem_path + asset_path)
)
return self._cache[asset_path]
def get_asset_fingerprint(self, asset_file_path):
return hashlib.md5( # nosec B324 - hash value is not verified, so md5 is fine
self.get_asset_file_contents(asset_file_path)
).hexdigest()
def get_asset_file_contents(self, asset_file_path):
with open(asset_file_path, "rb") as asset_file:
contents = asset_file.read()
return contents
asset_fingerprinter = AssetFingerprinter()