def __getitem__(self, key):
# if key is a slice, raise ProtocolUnbound
if isinstance(key, slice):
raise ProtocolUnbound('protocol slice unbound')
# if key is a protocol, then fetch protocol indexes
try:
flag = issubclass(key, Protocol)
except TypeError:
flag = issubclass(type(key), Protocol)
if flag or isinstance(key, Protocol):
key = key.__index__()
# make regex for tuple indexes
if isinstance(key, tuple):
key = r'|'.join(map(re.escape, key))
# if it's itself
if re.fullmatch(key, self.__class__.__name__, re.IGNORECASE):
return self
# then check recursively
from pcapkit.protocols.null import NoPayload
payload = self._next
while not isinstance(payload, NoPayload):
if re.fullmatch(key, payload.__class__.__name__, re.IGNORECASE):
return payload
payload = payload.payload
raise ProtocolNotFound(f"Layer {key!r} not in Frame")
def __getitem__(self, key):
"""Subscription (``getitem``) support.
* If ``key`` is a ``slice`` object, :exc:`ProtocolUnbound` will be
raised.
* If ``key`` is a :class`~pcapkit.protocols.protocol.Protocol` object,
the method will fetch its indexes
(:meth`~pcapkit.protocols.protocol.Protocol.__index__`).
* Later, search the packet's chain of protocols with the calculated
``key``.
* If no matches, then raises :exc:`ProtocolNotFound`.
Args:
key (Union[str, Protocol, Type[Protocol]]): Indexing key.
Returns:
Protocol: The sub-packet from the current packet of indexed protocol.
Raises:
ProtocolUnbound: If ``key`` is a ``slice`` object.
ProtocolNotFound: If ``key`` is not in the current packet.
"""
# if key is a slice, raise ProtocolUnbound
if isinstance(key, slice):
raise ProtocolUnbound('protocol slice unbound')
# if key is a protocol, then fetch protocol indexes
try:
flag = issubclass(key, Protocol)
except TypeError:
flag = issubclass(type(key), Protocol)
if flag or isinstance(key, Protocol):
key = key.__index__()
# make regex for tuple indexes
if isinstance(key, tuple):
key = r'|'.join(map(re.escape, key))
# if it's itself
if re.fullmatch(key, self.__class__.__name__, re.IGNORECASE):
return self
# then check recursively
from pcapkit.protocols.null import NoPayload # pylint: disable=import-outside-toplevel
payload = self._next
while not isinstance(payload, NoPayload):
if re.fullmatch(key, payload.__class__.__name__, re.IGNORECASE):
return payload
payload = payload.payload
raise ProtocolNotFound(f"Layer {key!r} not in Frame")