.. zephyr:code-sample:: coap-download
:name: CoAP download
:relevant-api: coap
Use the CoAP client API to download data via a GET request
Overview
********
This sample demonstrates the use of the CoAP client API to make GET requests to
a CoAP server. If the data to be fetched is larger than a single CoAP packet,
a blockwise transfer will be used to receive the data.
Once the transfer is complete, the sample prints the amount of data received
and the time taken.
Requirements
************
- :ref:`networking_with_host`, :ref:`networking_with_native_sim`
- or, a board with hardware networking (tested on nucleo_h753zi)
- Network connection between the board and host running a CoAP server
Build and Running
*****************
Build the CoAP download sample application like this:
.. zephyr-app-commands::
:zephyr-app: samples/net/sockets/coap_download
:board: <board to use>
:conf: <config file to use>
:goals: build
:compact:
The easiest way to run this sample application is to build and run it as a
native_sim application. Some setup is required as described in
:ref:`networking_with_native_sim`.
Download a CoAP server application, for example `aiocoap`_ (Python), or
`Eclipse Californium`_ (Java) has a demo `Simple File Server`_ application.
Using ``aiocoap``:
.. code-block:: bash
python -m pip install "aiocoap[all]"
mkdir file_root
echo "some test data" > file_root/test.txt
aiocoap-fileserver file_root
You can also change the name of the CoAP resource to request via Kconfig:
.. code-block:: cfg
CONFIG_NET_SAMPLE_COAP_RESOURCE_PATH="resource_name_to_request"
Launch :command:`net-setup.sh` in net-tools:
.. code-block:: bash
./net-setup.sh
Build and run the coap_download sample application for native_sim like this:
.. zephyr-app-commands::
:zephyr-app: samples/net/sockets/coap_download
:host-os: unix
:board: native_sim
:goals: run
:compact:
Sample output
=============
.. code-block:: console
[00:00:00.000,000] <inf> net_config: Initializing network
[00:00:00.000,000] <inf> net_config: IPv4 address: 192.0.2.1
[00:00:00.110,000] <inf> net_config: IPv6 address: 2001:db8::1
[00:00:00.110,000] <inf> net_config: IPv6 address: 2001:db8::1
[00:00:00.110,000] <inf> coap_download: Network L4 is connected
[00:00:00.110,000] <inf> coap_download: Starting CoAP download using IPv4
[00:00:00.180,000] <inf> coap_download: CoAP response, result_code=69, offset=0, len=100
[00:00:00.180,000] <inf> coap_download: CoAP download done, got 100 bytes in 70 ms
[00:00:00.180,000] <inf> coap_download: Starting CoAP download using IPv6
[00:00:00.300,000] <inf> coap_download: CoAP response, result_code=69, offset=0, len=100
[00:00:00.300,000] <inf> coap_download: CoAP download done, got 100 bytes in 120 ms
.. _aiocoap: https://github.com/chrysn/aiocoap
.. _Eclipse Californium: https://github.com/eclipse-californium/californium
.. _Simple File Server: https://github.com/eclipse-californium/californium/tree/main/demo-apps/cf-simplefile-server
fd613436d5