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from __future__ import with_statement
import os
import codecs
import urllib
from django.core.files.base import ContentFile
from django.template import Context
from django.template.loader import render_to_string
from django.utils.encoding import smart_unicode
from django.utils.importlib import import_module
from django.utils.safestring import mark_safe
from compressor.cache import get_hexdigest, get_mtime
from compressor.conf import settings
from compressor.exceptions import (CompressorError, UncompressableFileError,
from compressor.filters import CompilerFilter
from import default_storage, compressor_file_storage
from compressor.signals import post_compress
from compressor.utils import get_class, get_mod_func, staticfiles
from compressor.utils.decorators import cached_property
# Some constants for nicer handling.
SOURCE_HUNK, SOURCE_FILE = 'inline', 'file'
METHOD_INPUT, METHOD_OUTPUT = 'input', 'output'
class Compressor(object):
Base compressor object to be subclassed for content type
depending implementations details.
type = None
def __init__(self, content=None, output_prefix=None, context=None, *args, **kwargs):
self.content = content or ""
self.output_prefix = output_prefix or "compressed"
self.output_dir = settings.COMPRESS_OUTPUT_DIR.strip('/')
self.charset = settings.DEFAULT_CHARSET = default_storage
self.split_content = []
self.context = context or {}
self.extra_context = {}
self.all_mimetypes = dict(settings.COMPRESS_PRECOMPILERS)
self.finders = staticfiles.finders
def split_contents(self):
To be implemented in a subclass, should return an
iterable with four values: kind, value, basename, element
raise NotImplementedError
def get_template_name(self, mode):
Returns the template path for the given mode.
template = getattr(self, "template_name_%s" % mode)
if template:
return template
except AttributeError:
return "compressor/%s_%s.html" % (self.type, mode)
def get_basename(self, url):
base_url =
except AttributeError:
base_url = settings.COMPRESS_URL
if not url.startswith(base_url):
raise UncompressableFileError("'%s' isn't accessible via "
"COMPRESS_URL ('%s') and can't be "
"compressed" % (url, base_url))
basename = url.replace(base_url, "", 1)
# drop the querystring, which is used for non-compressed cache-busting.
return basename.split("?", 1)[0]
def get_filepath(self, content, basename=None):
parts = []
if basename:
filename = os.path.split(basename)[1]
parts.extend([get_hexdigest(content, 12), self.type])
return os.path.join(self.output_dir, self.output_prefix, '.'.join(parts))
def get_filename(self, basename):
filename = None
# first try finding the file in the root
# call path first so remote storages don't make it to exists,
# which would cause network I/O
filename =
if not
filename = None
except NotImplementedError:
# remote storages don't implement path, access the file locally
if compressor_file_storage.exists(basename):
filename = compressor_file_storage.path(basename)
# secondly try to find it with staticfiles (in debug mode)
if not filename and self.finders:
filename = self.finders.find(urllib.url2pathname(basename))
if filename:
return filename
# or just raise an exception as the last resort
raise UncompressableFileError(
"'%s' could not be found in the COMPRESS_ROOT '%s'%s" %
(basename, settings.COMPRESS_ROOT,
self.finders and " or with staticfiles." or "."))
def get_filecontent(self, filename, charset):
with, 'rb', charset) as fd:
except IOError, e:
raise UncompressableFileError("IOError while processing "
"'%s': %s" % (filename, e))
except UnicodeDecodeError, e:
raise UncompressableFileError("UnicodeDecodeError while "
"processing '%s' with "
"charset %s: %s" %
(filename, charset, e))
def parser(self):
return get_class(settings.COMPRESS_PARSER)(self.content)
def cached_filters(self):
return [get_class(filter_cls) for filter_cls in self.filters]
def mtimes(self):
return [str(get_mtime(value))
for kind, value, basename, elem in self.split_contents()
if kind == SOURCE_FILE]
def cachekey(self):
return get_hexdigest(''.join(
[self.content] + self.mtimes).encode(self.charset), 12)
def hunks(self, forced=False):
The heart of content parsing, iterates of the
list of split contents and looks at its kind
to decide what to do with it. Should yield a
bunch of precompiled and/or rendered hunks.
enabled = settings.COMPRESS_ENABLED or forced
for kind, value, basename, elem in self.split_contents():
precompiled = False
attribs = self.parser.elem_attribs(elem)
charset = attribs.get("charset", self.charset)
options = {
'method': METHOD_INPUT,
'elem': elem,
'kind': kind,
'basename': basename,
if kind == SOURCE_FILE:
options = dict(options, filename=value)
value = self.get_filecontent(value, charset)
if self.all_mimetypes:
precompiled, value = self.precompile(value, **options)
if enabled:
value = self.filter(value, **options)
yield smart_unicode(value, charset.lower())
if precompiled:
value = self.handle_output(kind, value, forced=True, basename=basename)
yield smart_unicode(value, charset.lower())
yield self.parser.elem_str(elem)
def filter_output(self, content):
Passes the concatenated content to the 'output' methods
of the compressor filters.
return self.filter(content, method=METHOD_OUTPUT)
def filter_input(self, forced=False):
Passes each hunk (file or code) to the 'input' methods
of the compressor filters.
content = []
for hunk in self.hunks(forced):
return content
def precompile(self, content, kind=None, elem=None, filename=None, **kwargs):
if not kind:
return False, content
attrs = self.parser.elem_attribs(elem)
mimetype = attrs.get("type", None)
if mimetype:
filter_or_command = self.all_mimetypes.get(mimetype)
if filter_or_command is None:
if mimetype not in ("text/css", "text/javascript"):
raise CompressorError("Couldn't find any precompiler in "
"mimetype '%s'." % mimetype)
mod_name, cls_name = get_mod_func(filter_or_command)
mod = import_module(mod_name)
except ImportError:
return True, CompilerFilter(content, filter_type=self.type,
command=filter_or_command, filename=filename).input(
precompiler_class = getattr(mod, cls_name)
except AttributeError:
raise FilterDoesNotExist('Could not find "%s".' %
return True, precompiler_class(content, attrs,
filter_type=self.type, filename=filename).input(
return False, content
def filter(self, content, method, **kwargs):
for filter_cls in self.cached_filters:
filter_func = getattr(
filter_cls(content, filter_type=self.type), method)
if callable(filter_func):
content = filter_func(**kwargs)
except NotImplementedError:
return content
def output(self, mode='file', forced=False):
The general output method, override in subclass if you need to do
any custom modification. Calls other mode specific methods or simply
returns the content directly.
content = self.filter_input(forced)
if not content:
return ''
output = '\n'.join(c.encode(self.charset) for c in content)
if settings.COMPRESS_ENABLED or forced:
filtered_output = self.filter_output(output)
return self.handle_output(mode, filtered_output, forced)
return output
def handle_output(self, mode, content, forced, basename=None):
# Then check for the appropriate output method and call it
output_func = getattr(self, "output_%s" % mode, None)
if callable(output_func):
return output_func(mode, content, forced, basename)
# Total failure, raise a general exception
raise CompressorError(
"Couldn't find output method for mode '%s'" % mode)
def output_file(self, mode, content, forced=False, basename=None):
The output method that saves the content to a file and renders
the appropriate template with the file's URL.
new_filepath = self.get_filepath(content, basename=basename)
if not or forced:, ContentFile(content))
url = mark_safe(
return self.render_output(mode, {"url": url})
def output_inline(self, mode, content, forced=False, basename=None):
The output method that directly returns the content for inline
return self.render_output(mode, {"content": content})
def render_output(self, mode, context=None):
Renders the compressor output with the appropriate template for
the given mode and template context.
# Just in case someone renders the compressor outside
# the usual template rendering cycle
if 'compressed' not in self.context:
self.context['compressed'] = {}
self.context['compressed'].update(context or {})
final_context = Context(self.context)
post_compress.send(sender=self.__class__, type=self.type,
mode=mode, context=final_context)
template_name = self.get_template_name(mode)
return render_to_string(template_name, context_instance=final_context)
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