def from_cbor_data(cls, obj):
if not isinstance(obj, dict):
raise link_header.ParseException("Entry is not a dict")
if any(k in _CBOR_ENCODING for k in obj):
# it says "MUST NOT accept"
raise link_header.ParseException("Unencoded attribute")
return cls.from_json_data(
{_CBOR_DECODING.get(k, k): v for (k, v) in obj.items()})
def from_json_string(cls, encoded):
import json
try:
array = json.loads(encoded)
except json.JSONDecodeError:
raise link_header.ParseException("Not valid JSON")
if not isinstance(array, list):
raise link_header.ParseException("Not a JSON array")
return cls(Link.from_json_data(x) for x in array)
def from_cbor_bytes(cls, encoded):
import cbor
try:
# FIXME: don't silently accept trailing bytes
array = cbor.loads(encoded)
except: # FIXME in library: give one subclassable "failure to decode" error
raise link_header.ParseException("Not valid CBOR")
if not isinstance(array, list):
raise link_header.ParseException("Not a CBOR array")
return cls(Link.from_cbor_data(x) for x in array)
def from_json_data(cls, obj):
if not isinstance(obj, dict):
raise link_header.ParseException("Entry is not a dict")
href = obj.get('href')
if not isinstance(href, str):
raise link_header.ParseException("href is not a single string")
link = Link(href)
for k, values in obj.items():
if not isinstance(values, list):
values = (values,)
for v in values:
if isinstance(v, str):
link.attr_pairs.append((k, v))
elif v is True:
link.attr_pairs.append((k, None))
elif isinstance(v, dict):
raise link_header.ParseException("Language tags not supported by link_header")
else:
raise link_header.ParseException("Unsupported value type")
return link