def validate_matching_preconditions(request, meta):
"""Check that the ETag conforms with the preconditions set."""
etag = meta['hash'] if not UPDATE_MD5 else meta['checksum']
if not etag:
etag = None
if_match = request.META.get('HTTP_IF_MATCH')
if if_match is not None:
if etag is None:
raise faults.PreconditionFailed('Resource does not exist')
if (if_match != '*'
and etag not in [x.lower() for x in parse_etags(if_match)]):
raise faults.PreconditionFailed('Resource ETag does not match')
if_none_match = request.META.get('HTTP_IF_NONE_MATCH')
if if_none_match is not None:
# TODO: If this passes, must ignore If-Modified-Since header.
if etag is not None:
if (if_none_match == '*' or etag in [x.lower() for x in
parse_etags(if_none_match)]):
# TODO: Continue if an If-Modified-Since header is present.
if request.method in ('HEAD', 'GET'):
raise faults.NotModified('Resource ETag matches')
raise faults.PreconditionFailed(
'Resource exists or ETag matches')
def validate_modification_preconditions(request, meta):
"""Check the modified timestamp conforms with the preconditions set."""
if 'modified' not in meta:
return # TODO: Always return?
if_modified_since = request.META.get('HTTP_IF_MODIFIED_SINCE')
if if_modified_since is not None:
if_modified_since = parse_http_date_safe(if_modified_since)
if (if_modified_since is not None
and int(meta['modified']) <= if_modified_since):
raise faults.NotModified('Resource has not been modified')
if_unmodified_since = request.META.get('HTTP_IF_UNMODIFIED_SINCE')
if if_unmodified_since is not None:
if_unmodified_since = parse_http_date_safe(if_unmodified_since)
if (if_unmodified_since is not None
and int(meta['modified']) > if_unmodified_since):
raise faults.PreconditionFailed('Resource has been modified')