class CachedFilesMixin(object):
default_template = """url("%s")"""
patterns = (
(
"*.css",
(
r"""(url\(['"]{0,1}\s*(.*?)["']{0,1}\))""",
(r"""(@import\s*["']\s*(.*?)["'])""", """@import url("%s")"""),
),
),
)
def __init__(self, *args, **kwargs):
super(CachedFilesMixin, self).__init__(*args, **kwargs)
try:
self.cache = get_cache("staticfiles")
except InvalidCacheBackendError:
# Use the default backend
self.cache = default_cache
self._patterns = SortedDict()
for extension, patterns in self.patterns:
for pattern in patterns:
if isinstance(pattern, (tuple, list)):
pattern, template = pattern
else:
template = self.default_template
compiled = re.compile(pattern)
self._patterns.setdefault(extension, []).append((compiled, template))
def file_hash(self, name, content=None):
"""
Retuns a hash of the file with the given name and optional content.
"""
if content is None:
return None
md5 = hashlib.md5()
for chunk in content.chunks():
md5.update(chunk)
return md5.hexdigest()[:12]
def hashed_name(self, name, content=None):
parsed_name = urlsplit(unquote(name))
clean_name = parsed_name.path.strip()
opened = False
if content is None:
if not self.exists(clean_name):
raise ValueError("The file '%s' could not be found with %r." % (clean_name, self))
try:
content = self.open(clean_name)
except IOError:
# Handle directory paths and fragments
return name
opened = True
try:
file_hash = self.file_hash(clean_name, content)
finally:
if opened:
content.close()
path, filename = os.path.split(clean_name)
root, ext = os.path.splitext(filename)
if file_hash is not None:
file_hash = ".%s" % file_hash
hashed_name = os.path.join(path, "%s%s%s" % (root, file_hash, ext))
unparsed_name = list(parsed_name)
unparsed_name[2] = hashed_name
# Special casing for a @font-face hack, like url(myfont.eot?#iefix")
# http://www.fontspring.com/blog/the-new-bulletproof-font-face-syntax
if "?#" in name and not unparsed_name[3]:
unparsed_name[2] += "?"
return urlunsplit(unparsed_name)
def cache_key(self, name):
return "staticfiles:%s" % hashlib.md5(force_bytes(name)).hexdigest()
def url(self, name, force=False):
"""
Returns the real URL in DEBUG mode.
"""
if settings.DEBUG and not force:
hashed_name, fragment = name, ""
else:
clean_name, fragment = urldefrag(name)
if urlsplit(clean_name).path.endswith("/"): # don't hash paths
hashed_name = name
else:
cache_key = self.cache_key(name)
hashed_name = self.cache.get(cache_key)
if hashed_name is None:
hashed_name = self.hashed_name(clean_name).replace("\\", "/")
# set the cache if there was a miss
# (e.g. if cache server goes down)
self.cache.set(cache_key, hashed_name)
final_url = super(CachedFilesMixin, self).url(hashed_name)
# Special casing for a @font-face hack, like url(myfont.eot?#iefix")
# http://www.fontspring.com/blog/the-new-bulletproof-font-face-syntax
query_fragment = "?#" in name # [sic!]
if fragment or query_fragment:
urlparts = list(urlsplit(final_url))
if fragment and not urlparts[4]:
urlparts[4] = fragment
if query_fragment and not urlparts[3]:
urlparts[2] += "?"
final_url = urlunsplit(urlparts)
return unquote(final_url)
def url_converter(self, name, template=None):
"""
Returns the custom URL converter for the given file name.
"""
if template is None:
template = self.default_template
def converter(matchobj):
"""
Converts the matched URL depending on the parent level (`..`)
and returns the normalized and hashed URL using the url method
of the storage.
"""
matched, url = matchobj.groups()
# Completely ignore http(s) prefixed URLs,
# fragments and data-uri URLs
if url.startswith(("#", "http:", "https:", "data:", "//")):
return matched
name_parts = name.split(os.sep)
# Using posix normpath here to remove duplicates
url = posixpath.normpath(url)
url_parts = url.split("/")
parent_level, sub_level = url.count(".."), url.count("/")
if url.startswith("/"):
sub_level -= 1
url_parts = url_parts[1:]
if parent_level or not url.startswith("/"):
start, end = parent_level + 1, parent_level
else:
if sub_level:
if sub_level == 1:
parent_level -= 1
start, end = parent_level, 1
else:
start, end = 1, sub_level - 1
joined_result = "/".join(name_parts[:-start] + url_parts[end:])
hashed_url = self.url(unquote(joined_result), force=True)
file_name = hashed_url.split("/")[-1:]
relative_url = "/".join(url.split("/")[:-1] + file_name)
# Return the hashed version to the file
return template % unquote(relative_url)
return converter
def post_process(self, paths, dry_run=False, **options):
"""
Post process the given list of files (called from collectstatic).
Processing is actually two separate operations:
1. renaming files to include a hash of their content for cache-busting,
and copying those files to the target storage.
2. adjusting files which contain references to other files so they
refer to the cache-busting filenames.
If either of these are performed on a file, then that file is considered
post-processed.
"""
# don't even dare to process the files if we're in dry run mode
if dry_run:
return
# where to store the new paths
hashed_paths = {}
# build a list of adjustable files
matches = lambda path: matches_patterns(path, self._patterns.keys())
adjustable_paths = [path for path in paths if matches(path)]
# then sort the files by the directory level
path_level = lambda name: len(name.split(os.sep))
for name in sorted(paths.keys(), key=path_level, reverse=True):
# use the original, local file, not the copied-but-unprocessed
# file, which might be somewhere far away, like S3
storage, path = paths[name]
with storage.open(path) as original_file:
# generate the hash with the original content, even for
# adjustable files.
hashed_name = self.hashed_name(name, original_file)
# then get the original's file content..
if hasattr(original_file, "seek"):
original_file.seek(0)
hashed_file_exists = self.exists(hashed_name)
processed = False
# ..to apply each replacement pattern to the content
if name in adjustable_paths:
content = original_file.read().decode(settings.FILE_CHARSET)
for patterns in self._patterns.values():
for pattern, template in patterns:
converter = self.url_converter(name, template)
content = pattern.sub(converter, content)
if hashed_file_exists:
self.delete(hashed_name)
# then save the processed result
content_file = ContentFile(force_bytes(content))
saved_name = self._save(hashed_name, content_file)
hashed_name = force_text(saved_name.replace("\\", "/"))
processed = True
else:
# or handle the case in which neither processing nor
# a change to the original file happened
if not hashed_file_exists:
processed = True
saved_name = self._save(hashed_name, original_file)
hashed_name = force_text(saved_name.replace("\\", "/"))
# and then set the cache accordingly
hashed_paths[self.cache_key(name.replace("\\", "/"))] = hashed_name
yield name, hashed_name, processed
# Finally set the cache
self.cache.set_many(hashed_paths)
