import logging
import re
from django.contrib.staticfiles.storage import staticfiles_storage
from django.contrib.staticfiles import finders
from django.conf import settings
from static_replace.models import AssetBaseUrlConfig, AssetExcludedExtensionsConfig
from xmodule.modulestore.django import modulestore
from xmodule.modulestore import ModuleStoreEnum
from xmodule.contentstore.content import StaticContent
from opaque_keys.edx.locator import AssetLocator
log = logging.getLogger(__name__)
XBLOCK_STATIC_RESOURCE_PREFIX = '/static/xblock'
def _url_replace_regex(prefix):
"""
Match static urls in quotes that don't end in '?raw'.
To anyone contemplating making this more complicated:
http://xkcd.com/1171/
"""
return ur"""
(?x) # flags=re.VERBOSE
(?P<quote>\\?['"]) # the opening quotes
(?P<prefix>{prefix}) # the prefix
(?P<rest>.*?) # everything else in the url
(?P=quote) # the first matching closing quote
""".format(prefix=prefix)
def try_staticfiles_lookup(path):
"""
Try to lookup a path in staticfiles_storage. If it fails, return
a dead link instead of raising an exception.
"""
try:
url = staticfiles_storage.url(path)
except Exception as err:
log.warning("staticfiles_storage couldn't find path {0}: {1}".format(
path, str(err)))
# Just return the original path; don't kill everything.
url = path
return url
def replace_jump_to_id_urls(text, course_id, jump_to_id_base_url):
"""
This will replace a link to another piece of courseware to a 'jump_to'
URL that will redirect to the right place in the courseware
NOTE: This is similar to replace_course_urls in terms of functionality
but it is intended to be used when we only have a 'id' that the
course author provides. This is much more helpful when using
Studio authored courses since they don't need to know the path. This
is also durable with respect to item moves.
text: The content over which to perform the subtitutions
course_id: The course_id in which this rewrite happens
jump_to_id_base_url:
A app-tier (e.g. LMS) absolute path to the base of the handler that will perform the
redirect. e.g. /courses/<org>/<course>/<run>/jump_to_id. NOTE the <id> will be appended to
the end of this URL at re-write time
output: <text> after the link rewriting rules are applied
"""
def replace_jump_to_id_url(match):
quote = match.group('quote')
rest = match.group('rest')
return "".join([quote, jump_to_id_base_url + rest, quote])
return re.sub(_url_replace_regex('/jump_to_id/'), replace_jump_to_id_url, text)
def replace_course_urls(text, course_key):
"""
Replace /course/$stuff urls with /courses/$course_id/$stuff urls
text: The text to replace
course_module: A CourseDescriptor
returns: text with the links replaced
"""
course_id = course_key.to_deprecated_string()
def replace_course_url(match):
quote = match.group('quote')
rest = match.group('rest')
return "".join([quote, '/courses/' + course_id + '/', rest, quote])
return re.sub(_url_replace_regex('/course/'), replace_course_url, text)
def process_static_urls(text, replacement_function, data_dir=None):
"""
Run an arbitrary replacement function on any urls matching the static file
directory
"""
def wrap_part_extraction(match):
"""
Unwraps a match group for the captures specified in _url_replace_regex
and forward them on as function arguments
"""
original = match.group(0)
prefix = match.group('prefix')
quote = match.group('quote')
rest = match.group('rest')
# Don't rewrite XBlock resource links. Probably wasn't a good idea that /static
# works for actual static assets and for magical course asset URLs....
full_url = prefix + rest
starts_with_static_url = full_url.startswith(unicode(settings.STATIC_URL))
starts_with_prefix = full_url.startswith(XBLOCK_STATIC_RESOURCE_PREFIX)
contains_prefix = XBLOCK_STATIC_RESOURCE_PREFIX in full_url
if starts_with_prefix or (starts_with_static_url and contains_prefix):
return original
return replacement_function(original, prefix, quote, rest)
return re.sub(
_url_replace_regex(u'(?:{static_url}|/static/)(?!{data_dir})'.format(
static_url=settings.STATIC_URL,
data_dir=data_dir
)),
wrap_part_extraction,
text
)
def make_static_urls_absolute(request, html):
"""
Converts relative URLs referencing static assets to absolute URLs
"""
def replace(__, prefix, quote, rest):
"""
Function to actually do a single relative -> absolute url replacement
"""
processed = request.build_absolute_uri(prefix + rest)
return quote + processed + quote
return process_static_urls(
html,
replace
)
def replace_static_urls(text, data_directory=None, course_id=None, static_asset_path=''):
"""
Replace /static/$stuff urls either with their correct url as generated by collectstatic,
(/static/$md5_hashed_stuff) or by the course-specific content static url
/static/$course_data_dir/$stuff, or, if course_namespace is not None, by the
correct url in the contentstore (/c4x/.. or /asset-loc:..)
text: The source text to do the substitution in
data_directory: The directory in which course data is stored
course_id: The course identifier used to distinguish static content for this course in studio
static_asset_path: Path for static assets, which overrides data_directory and course_namespace, if nonempty
"""
def replace_static_url(original, prefix, quote, rest):
"""
Replace a single matched url.
"""
# Don't mess with things that end in '?raw'
if rest.endswith('?raw'):
return original
# In debug mode, if we can find the url as is,
if settings.DEBUG and finders.find(rest, True):
return original
# if we're running with a MongoBacked store course_namespace is not None, then use studio style urls
elif (not static_asset_path) and course_id:
# first look in the static file pipeline and see if we are trying to reference
# a piece of static content which is in the edx-platform repo (e.g. JS associated with an xmodule)
exists_in_staticfiles_storage = False
try:
exists_in_staticfiles_storage = staticfiles_storage.exists(rest)
except Exception as err:
log.warning("staticfiles_storage couldn't find path {0}: {1}".format(
rest, str(err)))
if exists_in_staticfiles_storage:
url = staticfiles_storage.url(rest)
else:
# if not, then assume it's courseware specific content and then look in the
# Mongo-backed database
base_url = AssetBaseUrlConfig.get_base_url()
excluded_exts = AssetExcludedExtensionsConfig.get_excluded_extensions()
url = StaticContent.get_canonicalized_asset_path(course_id, rest, base_url, excluded_exts)
if AssetLocator.CANONICAL_NAMESPACE in url:
url = url.replace('block@', 'block/', 1)
# Otherwise, look the file up in staticfiles_storage, and append the data directory if needed
else:
course_path = "/".join((static_asset_path or data_directory, rest))
try:
if staticfiles_storage.exists(rest):
url = staticfiles_storage.url(rest)
else:
url = staticfiles_storage.url(course_path)
# And if that fails, assume that it's course content, and add manually data directory
except Exception as err:
log.warning("staticfiles_storage couldn't find path {0}: {1}".format(
rest, str(err)))
url = "".join([prefix, course_path])
return "".join([quote, url, quote])
return process_static_urls(text, replace_static_url, data_dir=static_asset_path or data_directory)