aiocoap.transports.tinydtls module

This module implements a MessageInterface that handles coaps:// using a wrapped tinydtls library.

This currently only implements the client side. To have a test server, run:

$ git clone https://github.com/obgm/libcoap.git --recursive
$ cd libcoap
$ ./autogen.sh
$ ./configure --with-tinydtls --disable-shared --disable-documentation
$ make
$ ./examples/coap-server -k secretPSK

(Using TinyDTLS in libcoap is important; with the default OpenSSL build, I’ve seen DTLS1.0 responses to DTLS1.3 requests, which are hard to debug.)

The test server with its built-in credentials can then be accessed using:

$ echo '{"coaps://localhost/*": {"dtls": {"psk": {"ascii": "secretPSK"}, "client-identity": {"ascii": "client_Identity"}}}}' > testserver.json
$ ./aiocoap-client coaps://localhost --credentials testserver.json

While it is planned to allow more programmatical construction of the credentials store, the currently recommended way of storing DTLS credentials is to load a structured data object into the client_credentials store of the context:

>>> c = await aiocoap.Context.create_client_context()          # doctest: +SKIP
>>> c.client_credentials.load_from_dict(
...     {'coaps://localhost/*': {'dtls': {
...         'psk': b'secretPSK',
...         'client-identity': b'client_Identity',
...         }}})                                               # doctest: +SKIP

where, compared to the JSON example above, byte strings can be used directly rather than expressing them as ‘ascii’/’hex’ ({‘hex’: ‘30383135’} style works as well) to work around JSON’s limitation of not having raw binary strings.

Bear in mind that the aiocoap CoAPS support is highly experimental; for example, while requests to this server do complete, error messages are still shown during client shutdown.

exception aiocoap.transports.tinydtls.CloseNotifyReceived

Bases: Exception

The DTLS connection a request was sent on raised was closed by the server while the request was being processed

exception aiocoap.transports.tinydtls.FatalDTLSError

Bases: Exception

The DTLS connection a request was sent on raised a fatal error while the request was being processed

class aiocoap.transports.tinydtls.DTLSClientConnection(host, port, pskId, psk, coaptransport)

Bases: aiocoap.interfaces.EndpointAddress

is_multicast = False

is_multicast_locally = False

uri_base

uri_base_local

scheme = 'coaps'

hostinfo_local

The authority component of URIs that this endpoint represents when requests are sent from it.

As with hostinfo, this does not necessarily produce sufficient input for a URI; use uri_local instead.

hostinfo = None

send(message)

log

shutdown()

class SingleConnection(parent)

Bases: object

classmethod factory(parent)

parent = None

DTLSClientConnection

connection_made(transport)

connection_lost(exc)

error_received(exc)

datagram_received(data, addr)

class aiocoap.transports.tinydtls.MessageInterfaceTinyDTLS(ctx: aiocoap.interfaces.MessageManager, log, loop)

Bases: aiocoap.interfaces.MessageInterface

classmethod create_client_transport_endpoint(ctx: aiocoap.interfaces.MessageManager, log, loop)

determine_remote(request)

Return a value suitable for the message’s remote property based on its .opt.uri_host or .unresolved_remote.

May return None, which indicates that the MessageInterface can not transport the message (typically because it is of the wrong scheme).

recognize_remote(remote)

shutdown()

Deactivate the complete transport, usually irrevertably. When the coroutine returns, the object must have made sure that it can be destructed by means of ref-counting or a garbage collector run.

send(message)

Send a given Message object