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.run(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.run(main())
Server¶
1import datetime
2import logging
3
4import asyncio
5
6import aiocoap.resource as resource
7from aiocoap.numbers.contentformat import ContentFormat
8import aiocoap
9
10class Welcome(resource.Resource):
11 representations = {
12 ContentFormat.TEXT: b"Welcome to the demo server",
13 ContentFormat.LINKFORMAT: b"</.well-known/core>,ct=40",
14 # ad-hoc for application/xhtml+xml;charset=utf-8
15 ContentFormat(65000):
16 b'<html xmlns="http://www.w3.org/1999/xhtml">'
17 b'<head><title>aiocoap demo</title></head>'
18 b'<body><h1>Welcome to the aiocoap demo server!</h1>'
19 b'<ul><li><a href="time">Current time</a></li>'
20 b'<li><a href="whoami">Report my network address</a></li>'
21 b'</ul></body></html>',
22 }
23
24 default_representation = ContentFormat.TEXT
25
26 async def render_get(self, request):
27 cf = self.default_representation if request.opt.accept is None else request.opt.accept
28 try:
29 return aiocoap.Message(payload=self.representations[cf], content_format=cf)
30 except KeyError:
31 raise aiocoap.error.UnsupportedContentFormat
32
33class BlockResource(resource.Resource):
34 """Example resource which supports the GET and PUT methods. It sends large
35 responses, which trigger blockwise transfer."""
36
37 def __init__(self):
38 super().__init__()
39 self.set_content(b"This is the resource's default content. It is padded "
40 b"with numbers to be large enough to trigger blockwise "
41 b"transfer.\n")
42
43 def set_content(self, content):
44 self.content = content
45 while len(self.content) <= 1024:
46 self.content = self.content + b"0123456789\n"
47
48 async def render_get(self, request):
49 return aiocoap.Message(payload=self.content)
50
51 async def render_put(self, request):
52 print('PUT payload: %s' % request.payload)
53 self.set_content(request.payload)
54 return aiocoap.Message(code=aiocoap.CHANGED, payload=self.content)
55
56
57class SeparateLargeResource(resource.Resource):
58 """Example resource which supports the GET method. It uses asyncio.sleep to
59 simulate a long-running operation, and thus forces the protocol to send
60 empty ACK first. """
61
62 def get_link_description(self):
63 # Publish additional data in .well-known/core
64 return dict(**super().get_link_description(), title="A large resource")
65
66 async def render_get(self, request):
67 await asyncio.sleep(3)
68
69 payload = "Three rings for the elven kings under the sky, seven rings "\
70 "for dwarven lords in their halls of stone, nine rings for "\
71 "mortal men doomed to die, one ring for the dark lord on his "\
72 "dark throne.".encode('ascii')
73 return aiocoap.Message(payload=payload)
74
75class TimeResource(resource.ObservableResource):
76 """Example resource that can be observed. The `notify` method keeps
77 scheduling itself, and calles `update_state` to trigger sending
78 notifications."""
79
80 def __init__(self):
81 super().__init__()
82
83 self.handle = None
84
85 def notify(self):
86 self.updated_state()
87 self.reschedule()
88
89 def reschedule(self):
90 self.handle = asyncio.get_event_loop().call_later(5, self.notify)
91
92 def update_observation_count(self, count):
93 if count and self.handle is None:
94 print("Starting the clock")
95 self.reschedule()
96 if count == 0 and self.handle:
97 print("Stopping the clock")
98 self.handle.cancel()
99 self.handle = None
100
101 async def render_get(self, request):
102 payload = datetime.datetime.now().\
103 strftime("%Y-%m-%d %H:%M").encode('ascii')
104 return aiocoap.Message(payload=payload)
105
106class WhoAmI(resource.Resource):
107 async def render_get(self, request):
108 text = ["Used protocol: %s." % request.remote.scheme]
109
110 text.append("Request came from %s." % request.remote.hostinfo)
111 text.append("The server address used %s." % request.remote.hostinfo_local)
112
113 claims = list(request.remote.authenticated_claims)
114 if claims:
115 text.append("Authenticated claims of the client: %s." % ", ".join(repr(c) for c in claims))
116 else:
117 text.append("No claims authenticated.")
118
119 return aiocoap.Message(content_format=0,
120 payload="\n".join(text).encode('utf8'))
121
122# logging setup
123
124logging.basicConfig(level=logging.INFO)
125logging.getLogger("coap-server").setLevel(logging.DEBUG)
126
127async def main():
128 # Resource tree creation
129 root = resource.Site()
130
131 root.add_resource(['.well-known', 'core'],
132 resource.WKCResource(root.get_resources_as_linkheader))
133 root.add_resource([], Welcome())
134 root.add_resource(['time'], TimeResource())
135 root.add_resource(['other', 'block'], BlockResource())
136 root.add_resource(['other', 'separate'], SeparateLargeResource())
137 root.add_resource(['whoami'], WhoAmI())
138
139 await aiocoap.Context.create_server_context(root)
140
141 # Run forever
142 await asyncio.get_running_loop().create_future()
143
144if __name__ == "__main__":
145 asyncio.run(main())