430b737760
components/coap/port/coap_mbedtls.c: Add in additional compile time check wrappers for different MbedTLS configurations. components/coap/CMakeLists.txt: components/coap/component.mk: components/coap/port/coap_notls.c: components/coap/port/include/coap_config_posix.h: Add in the ability to compile and run if MbedTLS does not have any TLS mode enabled. examples/protocols/coap_client/main/coap_client_example_main.c: Inform user that MbedTLS Client Mode is required for DTLS if not enabled, and coaps:// has been requested. [Lower libcoap library will still error and report this condition] examples/protocols/coap_server/main/coap_server_example_main.c: Inform user that MbedTLS Server Mode is required for DTLS if not enabled. [Lower libcoap library will still error and report this condition] Closes https://github.com/espressif/esp-idf/issues/3961 Closes https://github.com/espressif/esp-idf/issues/3971 Closes https://github.com/espressif/esp-idf/pull/3977 |
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| .. | ||
| main | ||
| CMakeLists.txt | ||
| Makefile | ||
| README.md | ||
CoAP server example
(See the README.md file in the upper level 'examples' directory for more information about examples.)
This CoAP server example is very simplified adaptation of one of the
libcoap examples.
CoAP server example will startup a daemon task, receive requests / data from CoAP client and transmit data to CoAP client.
If the incoming request requests the use of DTLS (connecting to port 5684), then the CoAP server will try to establish a DTLS session using the previously defined Pre-Shared Key (PSK) - which must be the same as the one that the CoAP client is using, or Public Key Infrastructure (PKI) where the PKI information must match as requested.
NOTE: Client sessions trying to use coaps+tcp:// are not currently supported, even though both libcoap and MbedTLS support it.
The Constrained Application Protocol (CoAP) is a specialized web transfer protocol for use with
constrained nodes and constrained networks in the Internet of Things.
The protocol is designed for machine-to-machine (M2M) applications such as smart energy and
building automation.
Please refer to RFC7252 for more details.
How to use example
Configure the project
idf.py menuconfig
Example Connection Configuration --->
- Set WiFi SSID under Example Configuration
- Set WiFi Password under Example Configuration Example CoAP Client Configuration --->
- If PSK, Set CoAP Preshared Key to use in connection to the server
Component config --->
CoAP Configuration --->
- Set encryption method definition, PSK (default) or PKI
- Enable CoAP debugging if required
Build and Flash
Build the project and flash it to the board, then run monitor tool to view serial output:
idf.py build
idf.py -p PORT flash monitor
(To exit the serial monitor, type Ctrl-].)
See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
Example Output
current CoAP server would startup a daemon task,
and the log is such as the following:
...
I (332) wifi: mode : sta (30:ae:a4:04:1b:7c)
I (1672) wifi: n:11 0, o:1 0, ap:255 255, sta:11 0, prof:1
I (1672) wifi: state: init -> auth (b0)
I (1682) wifi: state: auth -> assoc (0)
I (1692) wifi: state: assoc -> run (10)
I (1692) wifi: connected with huawei_cw, channel 11
I (1692) wifi: pm start, type: 1
I (2622) event: sta ip: 192.168.3.84, mask: 255.255.255.0, gw: 192.168.3.1
I (2622) CoAP_server: Connected to AP
...
If a CoAP client queries the /Espressif resource, CoAP server will return "Hello World!"
until a CoAP client does a PUT with different data.
libcoap Documentation
This can be found at https://libcoap.net/doc/reference/4.2.0/
Troubleshooting
-
Please make sure CoAP client fetchs or puts data under path:
/Espressifor fetches/.well-known/core -
CoAP logging can be enabled by running 'idf.py menuconfig -> Component config -> CoAP Configuration' and setting appropriate log level