Usage Examples

These files can serve as reference implementations for a simplistic server and client. In order to test them, run ./server.py in one terminal, and use ./clientGET.py and ./clientPUT.py to interact with it.

The programs’ source code should give you a good starting point to get familiar with the library if you prefer reading code to reading tutorials. Otherwise, you might want to have a look at the Guided Tour through aiocoap, where the relevant concepts are introduced and explained step by step.

Note

These example programs are not shipped in library version of aiocoap. They are present if you followed the Development version section of the installation instructions; otherwise, you can download them from the project website.

Client

 1import logging
 2import asyncio
 3
 4from aiocoap import *
 5
 6logging.basicConfig(level=logging.INFO)
 7
 8async def main():
 9    protocol = await Context.create_client_context()
10
11    request = Message(code=GET, uri='coap://localhost/time')
12
13    try:
14        response = await protocol.request(request).response
15    except Exception as e:
16        print('Failed to fetch resource:')
17        print(e)
18    else:
19        print('Result: %s\n%r'%(response.code, response.payload))
20
21if __name__ == "__main__":
22    asyncio.get_event_loop().run_until_complete(main())
 1import logging
 2import asyncio
 3
 4from aiocoap import *
 5
 6logging.basicConfig(level=logging.INFO)
 7
 8async def main():
 9    """Perform a single PUT request to localhost on the default port, URI
10    "/other/block". The request is sent 2 seconds after initialization.
11
12    The payload is bigger than 1kB, and thus sent as several blocks."""
13
14    context = await Context.create_client_context()
15
16    await asyncio.sleep(2)
17
18    payload = b"The quick brown fox jumps over the lazy dog.\n" * 30
19    request = Message(code=PUT, payload=payload, uri="coap://localhost/other/block")
20
21    response = await context.request(request).response
22
23    print('Result: %s\n%r'%(response.code, response.payload))
24
25if __name__ == "__main__":
26    asyncio.get_event_loop().run_until_complete(main())

Server

  1import datetime
  2import logging
  3
  4import asyncio
  5
  6import aiocoap.resource as resource
  7import aiocoap
  8
  9
 10class BlockResource(resource.Resource):
 11    """Example resource which supports the GET and PUT methods. It sends large
 12    responses, which trigger blockwise transfer."""
 13
 14    def __init__(self):
 15        super().__init__()
 16        self.set_content(b"This is the resource's default content. It is padded "\
 17                b"with numbers to be large enough to trigger blockwise "\
 18                b"transfer.\n")
 19
 20    def set_content(self, content):
 21        self.content = content
 22        while len(self.content) <= 1024:
 23            self.content = self.content + b"0123456789\n"
 24
 25    async def render_get(self, request):
 26        return aiocoap.Message(payload=self.content)
 27
 28    async def render_put(self, request):
 29        print('PUT payload: %s' % request.payload)
 30        self.set_content(request.payload)
 31        return aiocoap.Message(code=aiocoap.CHANGED, payload=self.content)
 32
 33
 34class SeparateLargeResource(resource.Resource):
 35    """Example resource which supports the GET method. It uses asyncio.sleep to
 36    simulate a long-running operation, and thus forces the protocol to send
 37    empty ACK first. """
 38
 39    def get_link_description(self):
 40        # Publish additional data in .well-known/core
 41        return dict(**super().get_link_description(), title="A large resource")
 42
 43    async def render_get(self, request):
 44        await asyncio.sleep(3)
 45
 46        payload = "Three rings for the elven kings under the sky, seven rings "\
 47                "for dwarven lords in their halls of stone, nine rings for "\
 48                "mortal men doomed to die, one ring for the dark lord on his "\
 49                "dark throne.".encode('ascii')
 50        return aiocoap.Message(payload=payload)
 51
 52class TimeResource(resource.ObservableResource):
 53    """Example resource that can be observed. The `notify` method keeps
 54    scheduling itself, and calles `update_state` to trigger sending
 55    notifications."""
 56
 57    def __init__(self):
 58        super().__init__()
 59
 60        self.handle = None
 61
 62    def notify(self):
 63        self.updated_state()
 64        self.reschedule()
 65
 66    def reschedule(self):
 67        self.handle = asyncio.get_event_loop().call_later(5, self.notify)
 68
 69    def update_observation_count(self, count):
 70        if count and self.handle is None:
 71            print("Starting the clock")
 72            self.reschedule()
 73        if count == 0 and self.handle:
 74            print("Stopping the clock")
 75            self.handle.cancel()
 76            self.handle = None
 77
 78    async def render_get(self, request):
 79        payload = datetime.datetime.now().\
 80                strftime("%Y-%m-%d %H:%M").encode('ascii')
 81        return aiocoap.Message(payload=payload)
 82
 83class WhoAmI(resource.Resource):
 84    async def render_get(self, request):
 85        text = ["Used protocol: %s." % request.remote.scheme]
 86
 87        text.append("Request came from %s." % request.remote.hostinfo)
 88        text.append("The server address used %s." % request.remote.hostinfo_local)
 89
 90        claims = list(request.remote.authenticated_claims)
 91        if claims:
 92            text.append("Authenticated claims of the client: %s." % ", ".join(repr(c) for c in claims))
 93        else:
 94            text.append("No claims authenticated.")
 95
 96        return aiocoap.Message(content_format=0,
 97                payload="\n".join(text).encode('utf8'))
 98
 99# logging setup
100
101logging.basicConfig(level=logging.INFO)
102logging.getLogger("coap-server").setLevel(logging.DEBUG)
103
104def main():
105    # Resource tree creation
106    root = resource.Site()
107
108    root.add_resource(['.well-known', 'core'],
109            resource.WKCResource(root.get_resources_as_linkheader))
110    root.add_resource(['time'], TimeResource())
111    root.add_resource(['other', 'block'], BlockResource())
112    root.add_resource(['other', 'separate'], SeparateLargeResource())
113    root.add_resource(['whoami'], WhoAmI())
114
115    asyncio.Task(aiocoap.Context.create_server_context(root))
116
117    asyncio.get_event_loop().run_forever()
118
119if __name__ == "__main__":
120    main()