Class HPackHdrString

scapy/contrib/http2.py:1300–1329

HPackHdrString is a packet that that is serialized into a RFC7541 par5.2 string literal repr.

class HPackHdrString(packet.Packet):
    """ HPackHdrString is a packet that that is serialized into a RFC7541 par5.2
    string literal repr.
    """
    name = 'HPack Header String'
    fields_desc = [
        fields.BitEnumField('type', None, 1, {0: 'Literal', 1: 'Compressed'}),
        FieldUVarLenField('len', None, 7, length_of='data'),
        HPackStrLenField(
            'data', HPackLiteralString(''),
            length_from=lambda pkt: pkt.getfieldval('len'),
            type_from='type'
        )
    ]

    def guess_payload_class(self, payload):
        # type: (str) -> Packet_metaclass
        # Trick to tell scapy that the remaining bytes of the currently
        # dissected string is not a payload of this packet but of some other
        # underlayer packet
        return config.conf.padding_layer

    def self_build(self, **kwargs):
        # type: (Any) -> str
        """self_build is overridden because type and len are determined at
        build time, based on the "data" field internal type
        """
        if self.getfieldval('type') is None:
            self.type = 1 if isinstance(self.getfieldval('data'), HPackZString) else 0  # noqa: E501
        return super(HPackHdrString, self).self_build(**kwargs)


class HPackHeaders(packet.Packet):