When we use css-sprites it's important to make browser cache them for longest period possible. On other hand, we need to refresh them when they are updated. This is especially visible when all icons are stored in single sprite. When it's outdated - entire site becomes ugly.
To solve this task I've implemented this small script that adds file's hash to url:
background-image: url(images/icons.png);
background-image: url(images/icons.png?a3844c660);#!/usr/bin/python
import os.path
import re
import hashlib
def file_hash(filename, block_size=2**20):
md5 = hashlib.md5()
with open(filename, 'rb') as f:
for data in iter(lambda: f.read(block_size), ''):
md5.update(data)
return md5.hexdigest()
def find_replace(match, basedir):
match = match.replace("'", '')
if '?' in match or '#' in match or match.startswith('http://'):
print 'skipping: ', match
return None
filename = os.path.join(basedir, match)
return '%s?%s' % (match, file_hash(filename)[:10])
def insert_hash(filename, debug=False):
basedir = os.path.dirname(filename)
css = open(filename).read()
matches = re.findall(r"url\((.*?)\)", css)
replacements = dict([
(match, find_replace(match, basedir))
for match in matches
])
if debug:
for key, value in replacements.iteritems():
print key, ' => ', value
else:
for match, repl in replacements.iteritems():
if repl:
css = css.replace(match, repl)
out = open(filename, 'w')
out.write(css)
out.close()
if __name__ == '__main__':
from optparse import OptionParser
usage = 'usage: %prog filename.css'
parser = OptionParser(usage=usage)
parser.add_option("", "--debug", action="store_true", dest="debug", default=False,
help="When set, just output list of substitutions.")
(options, args) = parser.parse_args()
if len(args) < 1:
print 'You must provide file name.'
insert_hash(os.path.realpath(args[0]), options.debug)Update
This is pretty old article. Now it's better to use something integrated to your build process - grunt, webassets, etc.
Subscribe for the news and updates
This article demonstrates how to use Python to automate yield calculations in decentralized finance (DeFi), focusing on the Renzo and Pendle platforms. It guides readers through estimating potential rewards based on factors like token prices, liquidity, and reward distribution rules, emphasizing the importance of regular data updates and informed decision-making in DeFi investments.
SQL is a fairly complicated language with a steep learning curve. For a large number of people who make use of SQL, learning to apply it efficiently takes lots of trials and errors. Here are some tips on how you can make your SELECT queries better. The majority of tips should be applicable to any relational database management system, but the terminology and exact namings will be taken from PostgreSQL.
Programmatic generation of PDF files is a frequent task when developing applications that can export reports, bills, or questionnaires. In this article, we will consider three common tools for creating PDFs, including their installation and converting principles.
This article is aimed for beginners, who are trying to choose between Ruby on Rails and Django. Let’s see which is fastest and why.
Quite often we have to write paginated or filtered blocks of information on page. I created a decorator that would automate this process.
There was a task to submit form with ajax, with server side validation of course. Obvious solution is to do validation and return json with erros. I didn't like idea of writing separate view for validation and then inserting errors in form html on client side. Especially since I already had a generic template for django form with errors display. In this article I'll describe how I solved the task.