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71 lines
2.5 KiB
Markdown
71 lines
2.5 KiB
Markdown
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# CoAP server example
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(See the README.md file in the upper level 'examples' directory for more information about examples.)
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This CoAP server example is adaptation of one of the [libcoap](https://github.com/obgm/libcoap) example.
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CoAP server example would startup a daemon task, receive data from CoAP client and transmit data to CoAP client.
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The Constrained Application Protocol (CoAP) is a specialized web transfer protocol for use with constrained nodes and constrained networks in the Internet of Things.
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The protocol is designed for machine-to-machine (M2M) applications such as smart energy and building automation.
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please refer to [RFC7252](https://www.rfc-editor.org/rfc/pdfrfc/rfc7252.txt.pdf) for more details.
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## How to use example
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### Configure the project
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```
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idf.py menuconfig
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```
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* Set default serial port under Serial Flasher config
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* Set WiFi SSID under Example Configuration
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* Set WiFi Password under Example Configuration
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* Set IPv4 multicast ip address for server to listen to
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* Set IPv6 multicast ip address for server to listen to
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### Build and Flash
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Build the project and flash it to the board, then run monitor tool to view serial output:
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```
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idf.py -p PORT flash monitor
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```
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(To exit the serial monitor, type ``Ctrl-]``.)
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See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
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## Example Output
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current CoAP server would startup a daemon task,
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and the log is such as the following:
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```
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...
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I (1828) wifi:state: 0 -> 2 (b0)
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I (1838) wifi:state: 2 -> 3 (0)
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I (1849) wifi:state: 3 -> 5 (10)
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I (1868) wifi:connected with HUAWEI_888, aid = 1, channel 1, HT20, bssid = 34:29:12:43:c5:40
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I (3829) tcpip_adapter: sta ip: 192.168.3.2, mask: 255.255.255.0, gw: 192.168.3.1
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I (3834) example_connect: Connected to HUAWEI_888
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I (3837) example_connect: IPv4 address: 192.168.3.2
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I (3846) example_connect: IPv6 address: fe80:0000:0000:0000:a6cf:12ff:fee8:733b
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I (3864) CoAP_server: Configured IPV4 Multicast address 232.10.11.12
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I (3875) CoAP_server: Configured IPV6 Multicast address ff02::fc
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...
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```
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if a CoAP client query `/Espressif` resource, CoAP server would return `"no data"`
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until a CoAP client does a PUT with some data.
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## libcoap Documentation
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This can be found at https://libcoap.net/doc/reference/4.2.0/
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## Troubleshooting
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* Please make sure CoAP client fetchs or puts data under path: `/Espressif` or
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fetches `/.well-known/core`
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* libcoap logging can be increased by changing `#define COAP_LOGGING_LEVEL 0`
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to `#define COAP_LOGGING_LEVEL 9`
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