bc9d1a65d7
This takes the code up to the latest released version of libcoap. As there have been API changes, coap_client and coap_server in examples/protocols have been updated to use the new APIs. Further information on the new libcoap APIs can be found at https://libcoap.net/doc/reference/4.2.0/ coap_client has been updated to handle BLOCK2 responses from "coap://californium.eclipse.org" coap_client has been modified to only send out one request (and wait for the response) coap_server has been updated to support Observe subscriptions, and well as adding in PUT and DELETE handlers to work on the Espressif resource coap_server and coap_client have had their stack sizes increased. port/coap_io.c has been added, a copy of libcoap/src/coap_io.c with support added for systems that do not have RFC 3542 section 20 support. port/coap_io_socket.c has been removed as a lot of the code is now replicated in different libcoap files. Once this PR is place, then adding in DTLS will be a lot simpler (as a separate PR) Signed-off-by: Jitin George <jitin@espressif.com> Merges https://github.com/espressif/esp-idf/pull/3148
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CoAP server example
(See the README.md file in the upper level 'examples' directory for more information about examples.)
This CoAP server example is adaptation of one of the libcoap example.
CoAP server example would startup a daemon task, receive data from CoAP client and transmit data to CoAP client.
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
make menuconfig
- Set default serial port under Serial Flasher config
- Set WiFi SSID under Example Configuration
- Set WiFi Password under Example Configuration
Build and Flash
Build the project and flash it to the board, then run monitor tool to view serial output:
make -j4 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 query /Espressif resource, CoAP server would return "no data"
until a CoAP client does a PUT with some 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 -
libcoap logging can be increased by changing
#define COAP_LOGGING_LEVEL 0to#define COAP_LOGGING_LEVEL 9