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 When it's outdated - entire site becomes ugly.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
Test analysis is an essential and crucial activity in the testing process. A well-organized test analysis provides an adequate level of confidence in the overall effectiveness of the testing and contributes to the delivery of high-quality software.
Django ORM is a very abstract and flexible API. But if you do not know exactly how it works, you will likely end up with slow and heavy views, if you have not already. So, this article provides practical solutions to N+1 and high loading time issues. For clarity, I will create a simple view that demonstrates common ORM query problems and shows frequently used practices.
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.
In this article, we will describe some useful scripts and directives we use with angular form validation in our projects.
In this article I will describe how to integrate geolocation HTML5 function to a web app so you can then easily implement it in your apps or websites. As an example we are going to create small web app which will be able to calculate the shortest route between detected user’s location and predefined destination using Google Maps API.
In VIM there is a command for char search: f. After first use it can be repeated with ;. I like to navigate in line with it. You see that you need to go to bracket in a middle of a line - you press f( and one-two ; and you are there. There's no such command in Emacs, so I had to write my own. I've managed even to implement repetition with ;.