def validate(self):
"""
Ensure the condition is valid according the local rules.
Checks the condition against the local bitmask (supported condition types)
and the local maximum fulfillment size.
Returns:
bool: Whether the condition is valid according to local rules.
"""
# Get class for type ID, throws on error
TypeRegistry.get_class_from_type_id(self.type_id)
# Bitmask can have at most 32 bits with current implementation
if self.bitmask > Condition.MAX_SAFE_BITMASK:
raise ValueError('Bitmask too large to be safely represented')
# Assert all requested features are supported by this implementation
if self.bitmask & ~Condition.SUPPORTED_BITMASK:
raise ValueError('Condition requested unsupported feature suites')
# Assert the requested fulfillment size is supported by this implementation
if self.max_fulfillment_length > Condition.MAX_FULFILLMENT_LENGTH:
raise ValueError('Condition requested too large of a max fulfillment size')
return True
def validate(self):
"""
Ensure the condition is valid according the local rules.
Checks the condition against the local bitmask (supported condition types)
and the local maximum fulfillment size.
Returns:
bool: Whether the condition is valid according to local rules.
"""
# Get class for type ID, throws on error
TypeRegistry.get_class_from_type_id(self.type_id)
# Bitmask can have at most 32 bits with current implementation
if self.bitmask > Condition.MAX_SAFE_BITMASK:
raise ValueError('Bitmask too large to be safely represented')
# Assert all requested features are supported by this implementation
if self.bitmask & ~Condition.SUPPORTED_BITMASK:
raise ValueError('Condition requested unsupported feature suites')
# Assert the requested fulfillment size is supported by this implementation
if self.max_fulfillment_length > Condition.MAX_FULFILLMENT_LENGTH:
raise ValueError(
'Condition requested too large of a max fulfillment size')
return True
def validate(self):
"""
Ensure the condition is valid according the local rules.
Checks the condition against the local subtypes (supported
condition types) and the local maximum fulfillment size.
Returns:
bool: Whether the condition is valid according to local rules.
"""
# Get class for type ID, throws on error
TypeRegistry.find_by_type_id(self.type_id)
# Subtypes can have at most 32 bits with current implementation
if len(self.subtypes) > Condition.MAX_SAFE_SUBTYPES:
raise ValueError('Subtypes too large to be safely represented')
# Assert all requested features are supported by this implementation
if any(subtype not in Condition.SUPPORTED_SUBTYPES
for subtype in self.subtypes):
raise ValueError('Condition requested unsupported feature suites')
# Assert the requested fulfillment size
# is supported by this implementation
if self.cost > Condition.MAX_COST:
raise ValueError(
'Condition requested too large of a max fulfillment size')
return True
def to_asn1_dict(self):
condition_type = TypeRegistry.find_by_type_id(self.type_id)
condition_class = condition_type['class']
payload = {'fingerprint': self.hash, 'cost': self.cost}
if condition_class.TYPE_CATEGORY == 'compound':
subtype_ids = [
TypeRegistry.find_by_name(subtype)['type_id']
for subtype in self.subtypes
]
bits = ['0' for bit in range(5)]
for subtype_id in subtype_ids:
bits[subtype_id] = '1'
bitstring = ''.join(bits).rstrip('0')
payload['subtypes'] = bitstring
return {condition_class.TYPE_ASN1: payload}
def from_uri(serialized_fulfillment):
"""
Create a Fulfillment object from a URI.
This method will parse a fulfillment URI and construct a corresponding Fulfillment object.
Args:
serialized_fulfillment (str): URI representing the fulfillment
Return:
Fulfillment: Resulting object
"""
if isinstance(serialized_fulfillment, Fulfillment):
return serialized_fulfillment
elif not isinstance(serialized_fulfillment, str):
raise TypeError('Serialized fulfillment must be a string')
pieces = serialized_fulfillment.split(':')
if not pieces[0] == 'cf':
raise ValueError('Serialized fulfillment must start with "cf:"')
if not re.match(Fulfillment.REGEX, serialized_fulfillment):
raise ValueError('Invalid fulfillment format')
# try:
type_id = int(pieces[1], 16)
payload = base64.urlsafe_b64decode(base64_add_padding(pieces[2]))
cls = TypeRegistry.get_class_from_type_id(type_id)
fulfillment = cls()
fulfillment.parse_payload(Reader.from_source(payload), len(payload))
# except Exception as e:
# raise ParsingError(str(e))
return fulfillment
def from_uri(serialized_condition):
"""
Create a Condition object from a URI.
This method will parse a condition URI and construct a corresponding Condition object.
Args:
serialized_condition (str): URI representing the condition
Returns:
Condition: Resulting object
"""
# TODO consider removing.
if isinstance(serialized_condition, Condition):
return serialized_condition
# TODO Use static typing instead (e.g.: with mypy).
elif not isinstance(serialized_condition, str):
raise TypeError('Serialized condition must be a string')
pieces = serialized_condition.split(':')
if pieces[0] != CONDITION_URI_SCHEME:
raise PrefixError(
'Serialized condition must start with "{}:"'.format(
CONDITION_URI_SCHEME
)
)
regex_match = re.match(CONDITION_REGEX_STRICT, serialized_condition)
if not regex_match:
raise ParsingError('Invalid condition format')
qs_dict = parse_qs(regex_match.group(2))
try:
fingerprint_type = qs_dict['fpt'][0]
except (KeyError, IndexError):
raise ParsingError(
'Invalid condition format: "fpt" parameter or value missing.')
condition_type = TypeRegistry.find_by_name(fingerprint_type)
try:
cost = qs_dict['cost'][0]
except (KeyError, IndexError):
raise ParsingError(
'Invalid condition format: "cost" parameter or value missing.')
if not re.match(INTEGER_REGEX, cost):
raise ParsingError('No or invalid cost provided')
fingerprint = regex_match.group(1)
condition = Condition()
condition.type_id = condition_type['type_id']
condition._subtypes = set()
if condition_type['class'].TYPE_CATEGORY == 'compound':
condition._subtypes.update(qs_dict['subtypes'][0].split(','))
condition.hash = base64.urlsafe_b64decode(
base64_add_padding(fingerprint))
condition.cost = int(cost)
return condition
def from_dict(data):
cls_type = data['type_id']
cls = TypeRegistry.get_class_from_type_id(cls_type)
fulfillment = cls()
fulfillment.parse_dict(data)
return fulfillment
def from_asn1_dict(asn1_dict):
asn1_type, value = asn1_dict.popitem()
registered_type = TypeRegistry.find_by_asn1_type(asn1_type)
# Instantiate condition
condition = Condition()
condition.type_id = registered_type['type_id']
condition.hash = value['fingerprint']
condition.cost = value['cost']
condition._subtypes = set()
if registered_type['class'].TYPE_CATEGORY == 'compound':
subtypes = {
TypeRegistry.find_by_type_id(type_id)['name']
for type_id in compress(
range(Condition.MAX_SAFE_SUBTYPES),
map(lambda bit: int(bit), value['subtypes'])
)
}
condition._subtypes.update(subtypes)
return condition
def serialize_uri(self):
"""
Generate the URI form encoding of this condition.
Turns the condition into a URI containing only URL-safe characters. This
format is convenient for passing around conditions in URLs, JSON and other text-based formats.
"cc:" BASE16(TYPE_ID) ":" BASE16(BITMASK) ":" BASE64URL(HASH) ":" BASE10(MAX_COST)
Returns:
string: Condition as a URI
"""
condition_type = TypeRegistry.find_by_type_id(self.type_id)
condition_class = TypeRegistry.find_by_type_id(self.type_id)['class']
include_subtypes = condition_class.TYPE_CATEGORY == 'compound'
uri = 'ni:///sha-256;{}?fpt={}&cost={}'.format(
base64_remove_padding(
base64.urlsafe_b64encode(self.hash)).decode(),
condition_type['name'],
self.cost,
)
if include_subtypes:
uri += '&subtypes=' + ','.join(sorted(self.subtypes))
return uri
def from_binary(reader):
"""
Create a Fulfillment object from a binary blob.
This method will parse a stream of binary data and construct a
corresponding Fulfillment object.
Args:
reader (Reader): Binary stream implementing the Reader interface
Returns:
Fulfillment: Resulting object
"""
reader = Reader.from_source(reader)
cls_type = reader.read_uint16()
cls = TypeRegistry.get_class_from_type_id(cls_type)
fulfillment = cls()
payload_length = reader.read_length_prefix()
fulfillment.parse_payload(reader, payload_length)
return fulfillment
def from_json(data):
type_ = TypeRegistry.find_by_name(data['type'])
fulfillment = type_['class']()
fulfillment.parse_json(data)
return fulfillment
def from_asn1_dict(asn1_dict):
asn1_type, value = asn1_dict.popitem()
instance = TypeRegistry.find_by_asn1_type(asn1_type)['class']()
instance.parse_asn1_dict_payload(value)
instance.asn1_dict = {asn1_type: value}
return instance
def from_json(data):
type_ = TypeRegistry.find_by_name(data['type'])
fulfillment = type_['class']()
fulfillment.parse_json(data)
return fulfillment
def from_asn1_dict(asn1_dict):
asn1_type, value = asn1_dict.popitem()
instance = TypeRegistry.find_by_asn1_type(asn1_type)['class']()
instance.parse_asn1_dict_payload(value)
instance.asn1_dict = {asn1_type: value}
return instance
def to_asn1_json(self):
asn1_type, value = self.to_asn1_dict().popitem()
condition_type = TypeRegistry.find_by_asn1_type(asn1_type)
return {'type': condition_type['asn1_condition'], 'value': value}
def type_name(self):
return TypeRegistry.find_by_type_id(self.type_id)['name']
