CoAPthon is a python library to the CoAP protocol compliant with 18th version of the draft. It is based on the Twisted Framework.

• CoAP server
• CoAP client asynchronous/synchronous
• CoAP to CoAP Forwarding proxy
• CoAP to CoAP Reverse Proxy
• Observe feature
• CoRE Link Format parsing
• Multicast server discovery

• CoAP to HTTP Proxy
• Blockwise feature

To install the library you need the pip program:

$ sudo apt-get install pip

Once you have the pip program issue the following commands:

$ cd CoAPthon
$ python setup.py sdist
$ sudo pip install dist/CoAPthon-2.0.0.tar.gz -r requirements.txt

The library is installed in the default path as well as the bins that you can use and customize. In order to start the example CoAP server issue:

$ coapserver.py

$ sudo pip uninstall CoAPthon

Log through ssh to the Yun and issue the following:

# opkg update #updates the available packages list
# opkg install distribute #it contains the easy_install command line tool
# opkg install python-openssl #adds ssl support to python
# easy_install pip #installs pip
# pip install bitstring
# pip install futures
# wget https://pypi.python.org/packages/source/T/Twisted/Twisted-14.0.2.tar.bz2 .
# tar -jxvf Twisted-14.0.2.tar.bz2
# cd Twisted-14.0.2

Then you need to modify the setup.py and comment the line conditionalExtensions=getExtensions(). Then :

# python setup.py build_py build_scripts install --skip-build

In order to implements a CoAP server the basic class must be extended. Moreover the server must add some resources.

from twisted.internet import reactor
from coapthon2.server.coap_protocol import CoAP
from example_resources import Hello


class CoAPServer(CoAP):
    def __init__(self):
        CoAP.__init__(self)
        self.add_resource('hello/', Hello())

def main():
    reactor.listenUDP(5683, CoAPServer())
    reactor.run()


if __name__ == '__main__':
    main()

Resources are extended from the class resource.Resource. Simple examples can be found in example_resource.py.

from coapthon2.resources.resource import Resource

class Hello(Resource):
    def __init__(self, name="HelloResource"):
        super(Hello, self).__init__(name, visible=True, observable=True, allow_children=True)
        self.payload = "Hello world!"

    def render_GET(self, query=None):
        return self.payload

    def render_PUT(self, payload=None, query=None):
        return payload

    def render_POST(self, payload=None, query=None):
        q = "?" + "&".join(query)
        res = Hello()
        return {"Payload": payload, "Location-Query": q, "Resource": res}

    def render_DELETE(self, query=None):
        return True

The documentation is based on the Sphinx framework. In order to build the documentation issue the following:

$ pip install Sphinx
$ cd CoAPthon/docs
$ make html

The documentation will be build in CoAPthon/docs/build/html. Let's start from index.html to have an overview of the library.