def test_delete(self):
set_cached_content(self.mockAsset)
del_cached_content(self.nonUnicodeLocation)
self.assertEqual(None, get_cached_content(self.unicodeLocation),
'should not be stored in cache with unicodeLocation')
self.assertEqual(None, get_cached_content(self.nonUnicodeLocation),
'should not be stored in cache with nonUnicodeLocation')
def test_delete(self):
set_cached_content(self.mockAsset)
del_cached_content(self.nonUnicodeLocation)
self.assertEqual(None, get_cached_content(self.unicodeLocation),
'should not be stored in cache with unicodeLocation')
self.assertEqual(None, get_cached_content(self.nonUnicodeLocation),
'should not be stored in cache with nonUnicodeLocation')
def test_put_and_get(self):
set_cached_content(self.mockAsset)
self.assertEqual(self.mockAsset.content,
get_cached_content(self.unicodeLocation).content,
'should be stored in cache with unicodeLocation')
self.assertEqual(self.mockAsset.content,
get_cached_content(self.nonUnicodeLocation).content,
'should be stored in cache with nonUnicodeLocation')
def test_put_and_get(self):
set_cached_content(self.mockAsset)
self.assertEqual(
self.mockAsset.content, get_cached_content(
self.unicodeLocation).content,
'should be stored in cache with unicodeLocation')
self.assertEqual(
self.mockAsset.content, get_cached_content(
self.nonUnicodeLocation).content,
'should be stored in cache with nonUnicodeLocation')
def process_request(self, request):
# look to see if the request is prefixed with 'c4x' tag
if request.path.startswith('/' + XASSET_LOCATION_TAG + '/'):
try:
loc = StaticContent.get_location_from_path(request.path)
except InvalidLocationError:
# return a 'Bad Request' to browser as we have a malformed Location
response = HttpResponse()
response.status_code = 400
return response
# first look in our cache so we don't have to round-trip to the DB
content = get_cached_content(loc)
if content is None:
# nope, not in cache, let's fetch from DB
try:
content = contentstore().find(loc, as_stream=True)
except NotFoundError:
response = HttpResponse()
response.status_code = 404
return response
# since we fetched it from DB, let's cache it going forward, but only if it's < 1MB
# this is because I haven't been able to find a means to stream data out of memcached
if content.length is not None:
if content.length < 1048576:
# since we've queried as a stream, let's read in the stream into memory to set in cache
content = content.copy_to_in_mem()
set_cached_content(content)
else:
# NOP here, but we may wish to add a "cache-hit" counter in the future
pass
# Check that user has access to content
if getattr(content, "locked", False):
if not hasattr(request,
"user") or not request.user.is_authenticated():
return HttpResponseForbidden('Unauthorized')
course_partial_id = "/".join([loc.org, loc.course])
if not request.user.is_staff and not CourseEnrollment.is_enrolled_by_partial(
request.user, course_partial_id):
return HttpResponseForbidden('Unauthorized')
# convert over the DB persistent last modified timestamp to a HTTP compatible
# timestamp, so we can simply compare the strings
last_modified_at_str = content.last_modified_at.strftime(
"%a, %d-%b-%Y %H:%M:%S GMT")
# see if the client has cached this content, if so then compare the
# timestamps, if they are the same then just return a 304 (Not Modified)
if 'HTTP_IF_MODIFIED_SINCE' in request.META:
if_modified_since = request.META['HTTP_IF_MODIFIED_SINCE']
if if_modified_since == last_modified_at_str:
return HttpResponseNotModified()
response = HttpResponse(content.stream_data(),
content_type=content.content_type)
response['Last-Modified'] = last_modified_at_str
return response
def process_request(self, request):
# look to see if the request is prefixed with 'c4x' tag
if request.path.startswith("/" + XASSET_LOCATION_TAG + "/"):
try:
loc = StaticContent.get_location_from_path(request.path)
except InvalidLocationError:
# return a 'Bad Request' to browser as we have a malformed Location
response = HttpResponse()
response.status_code = 400
return response
# first look in our cache so we don't have to round-trip to the DB
content = get_cached_content(loc)
if content is None:
# nope, not in cache, let's fetch from DB
try:
content = contentstore().find(loc, as_stream=True)
except NotFoundError:
response = HttpResponse()
response.status_code = 404
return response
# since we fetched it from DB, let's cache it going forward, but only if it's < 1MB
# this is because I haven't been able to find a means to stream data out of memcached
if content.length is not None:
if content.length < 1048576:
# since we've queried as a stream, let's read in the stream into memory to set in cache
content = content.copy_to_in_mem()
set_cached_content(content)
else:
# NOP here, but we may wish to add a "cache-hit" counter in the future
pass
# Check that user has access to content
if getattr(content, "locked", False):
if not hasattr(request, "user") or not request.user.is_authenticated():
return HttpResponseForbidden("Unauthorized")
course_partial_id = "/".join([loc.org, loc.course])
if not request.user.is_staff and not CourseEnrollment.is_enrolled_by_partial(
request.user, course_partial_id
):
return HttpResponseForbidden("Unauthorized")
# convert over the DB persistent last modified timestamp to a HTTP compatible
# timestamp, so we can simply compare the strings
last_modified_at_str = content.last_modified_at.strftime("%a, %d-%b-%Y %H:%M:%S GMT")
# see if the client has cached this content, if so then compare the
# timestamps, if they are the same then just return a 304 (Not Modified)
if "HTTP_IF_MODIFIED_SINCE" in request.META:
if_modified_since = request.META["HTTP_IF_MODIFIED_SINCE"]
if if_modified_since == last_modified_at_str:
return HttpResponseNotModified()
response = HttpResponse(content.stream_data(), content_type=content.content_type)
response["Last-Modified"] = last_modified_at_str
return response
def process_request(self, request):
# look to see if the request is prefixed with 'c4x' tag
if request.path.startswith('/' + XASSET_LOCATION_TAG + '/'):
try:
loc = StaticContent.get_location_from_path(request.path)
except InvalidLocationError:
# return a 'Bad Request' to browser as we have a malformed
# Location
response = HttpResponse()
response.status_code = 400
return response
# first look in our cache so we don't have to round-trip to the DB
content = get_cached_content(loc)
if content is None:
# nope, not in cache, let's fetch from DB
try:
content = contentstore().find(loc)
except NotFoundError:
response = HttpResponse()
response.status_code = 404
return response
# since we fetched it from DB, let's cache it going forward
set_cached_content(content)
else:
# @todo: we probably want to have 'cache hit' counters so we can
# measure the efficacy of our caches
pass
# see if the last-modified at hasn't changed, if not return a 302
# (Not Modified)
# convert over the DB persistent last modified timestamp to a HTTP compatible
# timestamp, so we can simply compare the strings
last_modified_at_str = content.last_modified_at.strftime(
"%a, %d-%b-%Y %H:%M:%S GMT")
# see if the client has cached this content, if so then compare the
# timestamps, if they are the same then just return a 304 (Not
# Modified)
if 'HTTP_IF_MODIFIED_SINCE' in request.META:
if_modified_since = request.META['HTTP_IF_MODIFIED_SINCE']
if if_modified_since == last_modified_at_str:
return HttpResponseNotModified()
response = HttpResponse(
content.data, content_type=content.content_type)
response['Last-Modified'] = last_modified_at_str
return response
def process_request(self, request):
# look to see if the request is prefixed with 'c4x' tag
if request.path.startswith('/' + XASSET_LOCATION_TAG + '/'):
try:
loc = StaticContent.get_location_from_path(request.path)
except InvalidLocationError:
# return a 'Bad Request' to browser as we have a malformed
# Location
response = HttpResponse()
response.status_code = 400
return response
# first look in our cache so we don't have to round-trip to the DB
content = get_cached_content(loc)
if content is None:
# nope, not in cache, let's fetch from DB
try:
content = contentstore().find(loc)
except NotFoundError:
response = HttpResponse()
response.status_code = 404
return response
# since we fetched it from DB, let's cache it going forward
set_cached_content(content)
else:
# @todo: we probably want to have 'cache hit' counters so we can
# measure the efficacy of our caches
pass
# see if the last-modified at hasn't changed, if not return a 302
# (Not Modified)
# convert over the DB persistent last modified timestamp to a HTTP compatible
# timestamp, so we can simply compare the strings
last_modified_at_str = content.last_modified_at.strftime(
"%a, %d-%b-%Y %H:%M:%S GMT")
# see if the client has cached this content, if so then compare the
# timestamps, if they are the same then just return a 304 (Not
# Modified)
if 'HTTP_IF_MODIFIED_SINCE' in request.META:
if_modified_since = request.META['HTTP_IF_MODIFIED_SINCE']
if if_modified_since == last_modified_at_str:
return HttpResponseNotModified()
response = HttpResponse(content.data,
content_type=content.content_type)
response['Last-Modified'] = last_modified_at_str
return response
def process_request(self, request):
# look to see if the request is prefixed with 'c4x' tag
if request.path.startswith('/' + XASSET_LOCATION_TAG + '/'):
try:
loc = StaticContent.get_location_from_path(request.path)
except InvalidLocationError:
# return a 'Bad Request' to browser as we have a malformed Location
response = HttpResponse()
response.status_code = 400
return response
# first look in our cache so we don't have to round-trip to the DB
content = get_cached_content(loc)
if content is None:
# nope, not in cache, let's fetch from DB
try:
content = contentstore().find(loc, as_stream=True)
except NotFoundError:
response = HttpResponse()
response.status_code = 404
return response
# since we fetched it from DB, let's cache it going forward, but only if it's < 1MB
# this is because I haven't been able to find a means to stream data out of memcached
if content.length is not None:
if content.length < 1048576:
# since we've queried as a stream, let's read in the stream into memory to set in cache
content = content.copy_to_in_mem()
set_cached_content(content)
else:
# NOP here, but we may wish to add a "cache-hit" counter in the future
pass
# see if the last-modified at hasn't changed, if not return a 302 (Not Modified)
# convert over the DB persistent last modified timestamp to a HTTP compatible
# timestamp, so we can simply compare the strings
last_modified_at_str = content.last_modified_at.strftime("%a, %d-%b-%Y %H:%M:%S GMT")
# see if the client has cached this content, if so then compare the
# timestamps, if they are the same then just return a 304 (Not Modified)
if 'HTTP_IF_MODIFIED_SINCE' in request.META:
if_modified_since = request.META['HTTP_IF_MODIFIED_SINCE']
if if_modified_since == last_modified_at_str:
return HttpResponseNotModified()
response = HttpResponse(content.stream_data(), content_type=content.content_type)
response['Last-Modified'] = last_modified_at_str
return response
def load_asset_from_location(self, location):
"""
Loads an asset based on its location, either retrieving it from a cache
or loading it directly from the contentstore.
"""
# See if we can load this item from cache.
content = get_cached_content(location)
if content is None:
# Not in cache, so just try and load it from the asset manager.
try:
content = AssetManager.find(location, as_stream=True)
except (ItemNotFoundError, NotFoundError):
raise
# Now that we fetched it, let's go ahead and try to cache it. We cap this at 1MB
# because it's the default for memcached and also we don't want to do too much
# buffering in memory when we're serving an actual request.
if content.length is not None and content.length < 1048576:
content = content.copy_to_in_mem()
set_cached_content(content)
return content
def load_asset_from_location(self, location):
"""
Loads an asset based on its location, either retrieving it from a cache
or loading it directly from the contentstore.
"""
# See if we can load this item from cache.
content = get_cached_content(location)
if content is None:
# Not in cache, so just try and load it from the asset manager.
try:
content = AssetManager.find(location, as_stream=True)
except (ItemNotFoundError, NotFoundError):
raise
# Now that we fetched it, let's go ahead and try to cache it. We cap this at 1MB
# because it's the default for memcached and also we don't want to do too much
# buffering in memory when we're serving an actual request.
if content.length is not None and content.length < 1048576:
content = content.copy_to_in_mem()
set_cached_content(content)
return content
def process_request(self, request):
# look to see if the request is prefixed with an asset prefix tag
if (request.path.startswith('/' + XASSET_LOCATION_TAG + '/')
or request.path.startswith('/' +
AssetLocator.CANONICAL_NAMESPACE)):
if AssetLocator.CANONICAL_NAMESPACE in request.path:
request.path = request.path.replace('block/', 'block@', 1)
try:
loc = StaticContent.get_location_from_path(request.path)
except (InvalidLocationError, InvalidKeyError):
# return a 'Bad Request' to browser as we have a malformed Location
response = HttpResponse()
response.status_code = 400
return response
# first look in our cache so we don't have to round-trip to the DB
content = get_cached_content(loc)
if content is None:
# nope, not in cache, let's fetch from DB
try:
content = AssetManager.find(loc, as_stream=True)
except (ItemNotFoundError, NotFoundError):
response = HttpResponse()
response.status_code = 404
return response
# since we fetched it from DB, let's cache it going forward, but only if it's < 1MB
# this is because I haven't been able to find a means to stream data out of memcached
if content.length is not None:
if content.length < 1048576:
# since we've queried as a stream, let's read in the stream into memory to set in cache
content = content.copy_to_in_mem()
set_cached_content(content)
else:
# NOP here, but we may wish to add a "cache-hit" counter in the future
pass
# Check that user has access to content
if getattr(content, "locked", False):
if not hasattr(request,
"user") or not request.user.is_authenticated():
return HttpResponseForbidden('Unauthorized')
if not request.user.is_staff:
if getattr(
loc, 'deprecated', False
) and not CourseEnrollment.is_enrolled_by_partial(
request.user, loc.course_key):
return HttpResponseForbidden('Unauthorized')
if not getattr(loc, 'deprecated',
False) and not CourseEnrollment.is_enrolled(
request.user, loc.course_key):
return HttpResponseForbidden('Unauthorized')
# convert over the DB persistent last modified timestamp to a HTTP compatible
# timestamp, so we can simply compare the strings
last_modified_at_str = content.last_modified_at.strftime(
"%a, %d-%b-%Y %H:%M:%S GMT")
# see if the client has cached this content, if so then compare the
# timestamps, if they are the same then just return a 304 (Not Modified)
if 'HTTP_IF_MODIFIED_SINCE' in request.META:
if_modified_since = request.META['HTTP_IF_MODIFIED_SINCE']
if if_modified_since == last_modified_at_str:
return HttpResponseNotModified()
# *** File streaming within a byte range ***
# If a Range is provided, parse Range attribute of the request
# Add Content-Range in the response if Range is structurally correct
# Request -> Range attribute structure: "Range: bytes=first-[last]"
# Response -> Content-Range attribute structure: "Content-Range: bytes first-last/totalLength"
# http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35
response = None
if request.META.get('HTTP_RANGE'):
# Data from cache (StaticContent) has no easy byte management, so we use the DB instead (StaticContentStream)
if type(content) == StaticContent:
content = AssetManager.find(loc, as_stream=True)
header_value = request.META['HTTP_RANGE']
try:
unit, ranges = parse_range_header(header_value,
content.length)
except ValueError as exception:
# If the header field is syntactically invalid it should be ignored.
log.exception(u"%s in Range header: %s for content: %s",
exception.message, header_value,
unicode(loc))
else:
if unit != 'bytes':
# Only accept ranges in bytes
log.warning(
u"Unknown unit in Range header: %s for content: %s",
header_value, unicode(loc))
elif len(ranges) > 1:
# According to Http/1.1 spec content for multiple ranges should be sent as a multipart message.
# http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.16
# But we send back the full content.
log.warning(
u"More than 1 ranges in Range header: %s for content: %s",
header_value, unicode(loc))
else:
first, last = ranges[0]
if 0 <= first <= last < content.length:
# If the byte range is satisfiable
response = HttpResponse(
content.stream_data_in_range(first, last))
response[
'Content-Range'] = 'bytes {first}-{last}/{length}'.format(
first=first,
last=last,
length=content.length)
response['Content-Length'] = str(last - first + 1)
response.status_code = 206 # Partial Content
else:
log.warning(
u"Cannot satisfy ranges in Range header: %s for content: %s",
header_value, unicode(loc))
return HttpResponse(
status=416) # Requested Range Not Satisfiable
# If Range header is absent or syntactically invalid return a full content response.
if response is None:
response = HttpResponse(content.stream_data())
response['Content-Length'] = content.length
# "Accept-Ranges: bytes" tells the user that only "bytes" ranges are allowed
response['Accept-Ranges'] = 'bytes'
response['Content-Type'] = content.content_type
response['Last-Modified'] = last_modified_at_str
return response
def process_request(self, request):
# look to see if the request is prefixed with an asset prefix tag
if (
request.path.startswith('/' + XASSET_LOCATION_TAG + '/') or
request.path.startswith('/' + AssetLocator.CANONICAL_NAMESPACE)
):
try:
loc = StaticContent.get_location_from_path(request.path)
except (InvalidLocationError, InvalidKeyError):
# return a 'Bad Request' to browser as we have a malformed Location
response = HttpResponse()
response.status_code = 400
return response
# first look in our cache so we don't have to round-trip to the DB
content = get_cached_content(loc)
if content is None:
# nope, not in cache, let's fetch from DB
try:
content = contentstore().find(loc, as_stream=True)
except NotFoundError:
response = HttpResponse()
response.status_code = 404
return response
# since we fetched it from DB, let's cache it going forward, but only if it's < 1MB
# this is because I haven't been able to find a means to stream data out of memcached
if content.length is not None:
if content.length < 1048576:
# since we've queried as a stream, let's read in the stream into memory to set in cache
content = content.copy_to_in_mem()
set_cached_content(content)
else:
# NOP here, but we may wish to add a "cache-hit" counter in the future
pass
# Check that user has access to content
if getattr(content, "locked", False):
if not hasattr(request, "user") or not request.user.is_authenticated():
return HttpResponseForbidden('Unauthorized')
if not request.user.is_staff:
if getattr(loc, 'deprecated', False) and not CourseEnrollment.is_enrolled_by_partial(
request.user, loc.course_key
):
return HttpResponseForbidden('Unauthorized')
if not getattr(loc, 'deprecated', False) and not CourseEnrollment.is_enrolled(
request.user, loc.course_key
):
return HttpResponseForbidden('Unauthorized')
# convert over the DB persistent last modified timestamp to a HTTP compatible
# timestamp, so we can simply compare the strings
last_modified_at_str = content.last_modified_at.strftime("%a, %d-%b-%Y %H:%M:%S GMT")
# see if the client has cached this content, if so then compare the
# timestamps, if they are the same then just return a 304 (Not Modified)
if 'HTTP_IF_MODIFIED_SINCE' in request.META:
if_modified_since = request.META['HTTP_IF_MODIFIED_SINCE']
if if_modified_since == last_modified_at_str:
return HttpResponseNotModified()
# *** File streaming within a byte range ***
# If a Range is provided, parse Range attribute of the request
# Add Content-Range in the response if Range is structurally correct
# Request -> Range attribute structure: "Range: bytes=first-[last]"
# Response -> Content-Range attribute structure: "Content-Range: bytes first-last/totalLength"
# http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35
response = None
if request.META.get('HTTP_RANGE'):
# Data from cache (StaticContent) has no easy byte management, so we use the DB instead (StaticContentStream)
if type(content) == StaticContent:
content = contentstore().find(loc, as_stream=True)
header_value = request.META['HTTP_RANGE']
try:
unit, ranges = parse_range_header(header_value, content.length)
except ValueError as exception:
# If the header field is syntactically invalid it should be ignored.
log.exception(
u"%s in Range header: %s for content: %s", exception.message, header_value, unicode(loc)
)
else:
if unit != 'bytes':
# Only accept ranges in bytes
log.warning(u"Unknown unit in Range header: %s for content: %s", header_value, unicode(loc))
elif len(ranges) > 1:
# According to Http/1.1 spec content for multiple ranges should be sent as a multipart message.
# http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.16
# But we send back the full content.
log.warning(
u"More than 1 ranges in Range header: %s for content: %s", header_value, unicode(loc)
)
else:
first, last = ranges[0]
if 0 <= first <= last < content.length:
# If the byte range is satisfiable
response = HttpResponse(content.stream_data_in_range(first, last))
response['Content-Range'] = 'bytes {first}-{last}/{length}'.format(
first=first, last=last, length=content.length
)
response['Content-Length'] = str(last - first + 1)
response.status_code = 206 # Partial Content
else:
log.warning(
u"Cannot satisfy ranges in Range header: %s for content: %s", header_value, unicode(loc)
)
return HttpResponse(status=416) # Requested Range Not Satisfiable
# If Range header is absent or syntactically invalid return a full content response.
if response is None:
response = HttpResponse(content.stream_data())
response['Content-Length'] = content.length
# "Accept-Ranges: bytes" tells the user that only "bytes" ranges are allowed
response['Accept-Ranges'] = 'bytes'
response['Content-Type'] = content.content_type
response['Last-Modified'] = last_modified_at_str
return response
def process_request(self, request):
# look to see if the request is prefixed with an asset prefix tag
if request.path.startswith("/" + XASSET_LOCATION_TAG + "/") or request.path.startswith(
"/" + AssetLocator.CANONICAL_NAMESPACE
):
try:
loc = StaticContent.get_location_from_path(request.path)
except (InvalidLocationError, InvalidKeyError):
# return a 'Bad Request' to browser as we have a malformed Location
response = HttpResponse()
response.status_code = 400
return response
# first look in our cache so we don't have to round-trip to the DB
content = get_cached_content(loc)
if content is None:
# nope, not in cache, let's fetch from DB
try:
content = contentstore().find(loc, as_stream=True)
except NotFoundError:
response = HttpResponse()
response.status_code = 404
return response
# since we fetched it from DB, let's cache it going forward, but only if it's < 1MB
# this is because I haven't been able to find a means to stream data out of memcached
if content.length is not None:
if content.length < 1048576:
# since we've queried as a stream, let's read in the stream into memory to set in cache
content = content.copy_to_in_mem()
set_cached_content(content)
else:
# NOP here, but we may wish to add a "cache-hit" counter in the future
pass
# Check that user has access to content
if getattr(content, "locked", False):
if not hasattr(request, "user") or not request.user.is_authenticated():
return HttpResponseForbidden("Unauthorized")
if not request.user.is_staff:
if getattr(loc, "deprecated", False) and not CourseEnrollment.is_enrolled_by_partial(
request.user, loc.course_key
):
return HttpResponseForbidden("Unauthorized")
if not getattr(loc, "deprecated", False) and not CourseEnrollment.is_enrolled(
request.user, loc.course_key
):
return HttpResponseForbidden("Unauthorized")
# convert over the DB persistent last modified timestamp to a HTTP compatible
# timestamp, so we can simply compare the strings
last_modified_at_str = content.last_modified_at.strftime("%a, %d-%b-%Y %H:%M:%S GMT")
# see if the client has cached this content, if so then compare the
# timestamps, if they are the same then just return a 304 (Not Modified)
if "HTTP_IF_MODIFIED_SINCE" in request.META:
if_modified_since = request.META["HTTP_IF_MODIFIED_SINCE"]
if if_modified_since == last_modified_at_str:
return HttpResponseNotModified()
# *** File streaming within a byte range ***
# If a Range is provided, parse Range attribute of the request
# Add Content-Range in the response if Range is structurally correct
# Request -> Range attribute structure: "Range: bytes=first-[last]"
# Response -> Content-Range attribute structure: "Content-Range: bytes first-last/totalLength"
response = None
if request.META.get("HTTP_RANGE"):
# Data from cache (StaticContent) has no easy byte management, so we use the DB instead (StaticContentStream)
if type(content) == StaticContent:
content = contentstore().find(loc, as_stream=True)
# Let's parse the Range header, bytes=first-[last]
range_header = request.META["HTTP_RANGE"]
if "=" in range_header:
unit, byte_range = range_header.split("=")
# "Accept-Ranges: bytes" tells the user that only "bytes" ranges are allowed
if unit == "bytes" and "-" in byte_range:
first, last = byte_range.split("-")
# "first" must be a valid integer
try:
first = int(first)
except ValueError:
pass
if type(first) is int:
# "last" default value is the last byte of the file
# Users can ask "bytes=0-" to request the whole file when they don't know the length
try:
last = int(last)
except ValueError:
last = content.length - 1
if 0 <= first <= last < content.length:
# Valid Range attribute
response = HttpResponse(content.stream_data_in_range(first, last))
response["Content-Range"] = "bytes {first}-{last}/{length}".format(
first=first, last=last, length=content.length
)
response["Content-Length"] = str(last - first + 1)
response.status_code = 206 # HTTP_206_PARTIAL_CONTENT
if not response:
# Malformed Range attribute
response = HttpResponse()
response.status_code = 400 # HTTP_400_BAD_REQUEST
return response
else:
# No Range attribute
response = HttpResponse(content.stream_data())
response["Content-Length"] = content.length
response["Accept-Ranges"] = "bytes"
response["Content-Type"] = content.content_type
response["Last-Modified"] = last_modified_at_str
return response
def process_request(self, request):
# look to see if the request is prefixed with an asset prefix tag
if (request.path.startswith('/' + XASSET_LOCATION_TAG + '/')
or request.path.startswith('/' +
AssetLocator.CANONICAL_NAMESPACE)):
try:
loc = StaticContent.get_location_from_path(request.path)
except (InvalidLocationError, InvalidKeyError):
# return a 'Bad Request' to browser as we have a malformed Location
response = HttpResponse()
response.status_code = 400
return response
# first look in our cache so we don't have to round-trip to the DB
content = get_cached_content(loc)
if content is None:
# nope, not in cache, let's fetch from DB
try:
content = contentstore().find(loc, as_stream=True)
except NotFoundError:
response = HttpResponse()
response.status_code = 404
return response
# since we fetched it from DB, let's cache it going forward, but only if it's < 1MB
# this is because I haven't been able to find a means to stream data out of memcached
if content.length is not None:
if content.length < 1048576:
# since we've queried as a stream, let's read in the stream into memory to set in cache
content = content.copy_to_in_mem()
set_cached_content(content)
else:
# NOP here, but we may wish to add a "cache-hit" counter in the future
pass
# Check that user has access to content
if getattr(content, "locked", False):
if not hasattr(request,
"user") or not request.user.is_authenticated():
return HttpResponseForbidden('Unauthorized')
if not request.user.is_staff:
if getattr(
loc, 'deprecated', False
) and not CourseEnrollment.is_enrolled_by_partial(
request.user, loc.course_key):
return HttpResponseForbidden('Unauthorized')
if not getattr(loc, 'deprecated',
False) and not CourseEnrollment.is_enrolled(
request.user, loc.course_key):
return HttpResponseForbidden('Unauthorized')
# convert over the DB persistent last modified timestamp to a HTTP compatible
# timestamp, so we can simply compare the strings
last_modified_at_str = content.last_modified_at.strftime(
"%a, %d-%b-%Y %H:%M:%S GMT")
# see if the client has cached this content, if so then compare the
# timestamps, if they are the same then just return a 304 (Not Modified)
if 'HTTP_IF_MODIFIED_SINCE' in request.META:
if_modified_since = request.META['HTTP_IF_MODIFIED_SINCE']
if if_modified_since == last_modified_at_str:
return HttpResponseNotModified()
# *** File streaming within a byte range ***
# If a Range is provided, parse Range attribute of the request
# Add Content-Range in the response if Range is structurally correct
# Request -> Range attribute structure: "Range: bytes=first-[last]"
# Response -> Content-Range attribute structure: "Content-Range: bytes first-last/totalLength"
response = None
if request.META.get('HTTP_RANGE'):
# Data from cache (StaticContent) has no easy byte management, so we use the DB instead (StaticContentStream)
if type(content) == StaticContent:
content = contentstore().find(loc, as_stream=True)
# Let's parse the Range header, bytes=first-[last]
range_header = request.META['HTTP_RANGE']
if '=' in range_header:
unit, byte_range = range_header.split('=')
# "Accept-Ranges: bytes" tells the user that only "bytes" ranges are allowed
if unit == 'bytes' and '-' in byte_range:
first, last = byte_range.split('-')
# "first" must be a valid integer
try:
first = int(first)
except ValueError:
pass
if type(first) is int:
# "last" default value is the last byte of the file
# Users can ask "bytes=0-" to request the whole file when they don't know the length
try:
last = int(last)
except ValueError:
last = content.length - 1
if 0 <= first <= last < content.length:
# Valid Range attribute
response = HttpResponse(
content.stream_data_in_range(first, last))
response[
'Content-Range'] = 'bytes {first}-{last}/{length}'.format(
first=first,
last=last,
length=content.length)
response['Content-Length'] = str(last - first +
1)
response.status_code = 206 # HTTP_206_PARTIAL_CONTENT
if not response:
# Malformed Range attribute
response = HttpResponse()
response.status_code = 400 # HTTP_400_BAD_REQUEST
return response
else:
# No Range attribute
response = HttpResponse(content.stream_data())
response['Content-Length'] = content.length
response['Accept-Ranges'] = 'bytes'
response['Content-Type'] = content.content_type
response['Last-Modified'] = last_modified_at_str
return response
