3c52d6727c
Added a compile warning and documented the limitation in the README.
2.5 KiB
2.5 KiB
A Quick Introduction to the Erbium (Er) CoAP Engine
EXAMPLE FILES
- coap-example-server.c: A CoAP server example showing how to use the CoAP layer to develop server-side applications.
- coap-example-client.c: A CoAP client that polls the /actuators/toggle resource every 10 seconds and cycles through 4 resources on button press (target address is hard-coded).
- plugtest-server.c: The server used for draft compliance testing at ETSI IoT CoAP Plugtests. Erbium (Er) participated in Paris, France, March 2012 and Sophia-Antipolis, France, November 2012 (configured for native).
PRELIMINARIES
- Get the Copper (Cu) CoAP user-agent from https://addons.mozilla.org/en-US/firefox/addon/copper-270430
TMOTE SKY HOWTO
The CoAP example no longer fits in the limited ROM of the Tmote Sky. Please use a platform with larger ROM instead.
NATIVE HOWTO
With the target native you can test your CoAP applications without constraints, i.e., with large buffers, debug output, memory protection, etc. The plugtest-server is thought for the native platform, as it requires an 1280-byte IP buffer and 1024-byte blocks.
make TARGET=native plugtest-server
sudo ./plugtest-server.native
Open new terminal
make connect-native
- Start Copper and discover resources at coap://[fdfd::ff:fe00:10]:5683/
- You can enable the ETSI Plugtest menu in Copper's preferences
Under Windows/Cygwin, WPCAP might need a patch in \usr\include\w32api\in6addr.h:
21,23c21
< #ifdef __INSIDE_CYGWIN__
< uint32_t __s6_addr32[4];
< #endif
---
> u_int __s6_addr32[4];
36d33
< #ifdef __INSIDE_CYGWIN__
39d35
< #endif
DETAILS
Erbium implements the Proposed Standard of CoAP. Central features are commented in coap-example-server.c. In general, coap supports:
- All draft-18 header options
- CON Retransmissions (note COAP_MAX_OPEN_TRANSACTIONS)
- Blockwise Transfers (note COAP_MAX_CHUNK_SIZE, see plugtest-server.c for Block1 uploads)
- Separate Responses (no rest_set_pre_handler() required anymore, note coap_separate_accept(), _reject(), and _resume())
- Resource Discovery
- Observing Resources (see EVENT_ and PERIODIC_RESOURCE, note COAP_MAX_OBSERVERS)
TODOs
- Dedicated Observe buffers
- Optimize message struct variable access (directly access struct without copying)
- Observe client
- Multiple If-Match ETags
- (Message deduplication)