aiocoap.optiontypes module

class aiocoap.optiontypes.OptionType(number, value)

Bases: object

Interface for decoding and encoding option values

Instances of OptionType are collected in a list in a Message.opt Options object, and provide a translation between the CoAP octet-stream (accessed using the encode()/decode() method pair) and the interpreted value (accessed via the value attribute).

Note that OptionType objects usually don’t need to be handled by library users; the recommended way to read and set options is via the Options object’sproperties (eg. message.opt.uri_path = ('.well-known', 'core')).

abstractmethod encode()

Return the option’s value in serialized form

abstractmethod decode(rawdata)

Set the option’s value from the bytes in rawdata

class aiocoap.optiontypes.StringOption(number, value='')

Bases: OptionType

String CoAP option - used to represent string options. Always encoded in UTF8 per CoAP specification.

encode()

Return the option’s value in serialized form

decode(rawdata)

Set the option’s value from the bytes in rawdata

class aiocoap.optiontypes.OpaqueOption(number, value=b'')

Bases: OptionType

Opaque CoAP option - used to represent options that just have their uninterpreted bytes as value.

encode()

Return the option’s value in serialized form

decode(rawdata)

Set the option’s value from the bytes in rawdata

class aiocoap.optiontypes.UintOption(number, value=0)

Bases: OptionType

Uint CoAP option - used to represent integer options.

encode()

Return the option’s value in serialized form

decode(rawdata)

Set the option’s value from the bytes in rawdata

class aiocoap.optiontypes.TypedOption(number, value=None)

Bases: OptionType

abstract property type: type

Checked type of the option

property value

class aiocoap.optiontypes.BlockOption(number, value=None)

Bases: TypedOption

Block CoAP option - special option used only for Block1 and Block2 options. Currently it is the only type of CoAP options that has internal structure.

That structure (BlockwiseTuple) covers not only the block options of RFC7959, but also the BERT extension of RFC8323. If the reserved size exponent 7 is used for purposes incompatible with BERT, the implementer might want to look at the context dependent option number interpretations which will hopefully be in place for Signaling (7.xx) messages by then.

class BlockwiseTuple(block_number, more, size_exponent)

Bases: _BlockwiseTuple

property size

property start

The byte offset in the body indicated by block number and size.

Note that this calculation is only valid for descriptive use and Block2 control use. The semantics of block_number and size in Block1 control use are unrelated (indicating the acknowledged block number in the request Block1 size and the server’s preferred block size), and must not be calculated using this property in that case.

property is_bert

True if the exponent is recognized to signal a BERT message.

is_valid_for_payload_size(payloadsize)

reduced_to(maximum_exponent)

Return a BlockwiseTuple whose exponent is capped to the given maximum_exponent

>>> initial = BlockOption.BlockwiseTuple(10, 0, 5)
>>> initial == initial.reduced_to(6)
True
>>> initial.reduced_to(3)
BlockwiseTuple(block_number=40, more=0, size_exponent=3)

type

alias of BlockwiseTuple

encode()

Return the option’s value in serialized form

decode(rawdata)

Set the option’s value from the bytes in rawdata

class aiocoap.optiontypes.ContentFormatOption(number, value=None)

Bases: TypedOption

Type of numeric options whose number has ContentFormat semantics

type

alias of ContentFormat

encode()

Return the option’s value in serialized form

decode(rawdata)

Set the option’s value from the bytes in rawdata