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Socket HTTP GET Example

Overview

The sockets/http_get sample application for Zephyr implements a simple HTTP GET client using a BSD Sockets compatible API. The purpose of this sample is to show how it’s possible to develop a sockets application portable to both POSIX and Zephyr. As such, it is kept minimal and supports only IPv4.

The source code for this sample application can be found at: samples/net/sockets/http_get.

Requirements

  • Networking with the host system

  • or, a board with hardware networking

  • NAT/routing should be set up to allow connections to the Internet

  • DNS server should be available on the host to resolve domain names

Building and Running

Build the Zephyr version of the application like this:

west build -b <board_to_use> samples/net/sockets/http_get

After the sample starts, it issues HTTP GET request to “google.com:80” and dumps the response. You can edit the source code to issue a request to any other site on the Internet (or on the local network, in which case no NAT/routing setup is needed). Exit QEMU by pressing CTRL+A x.

Enabling TLS support

Enable TLS support in the sample by building the project with the overlay-tls.conf overlay file enabled, for example, using these commands:

west build -b qemu_x86 samples/net/sockets/http_get -- -DCONF_FILE="prj.conf overlay-tls.conf"

An alternative way is to specify -DOVERLAY_CONFIG=overlay-tls.conf when running west build or cmake.

For boards that support TLS offloading (e.g. TI’s cc3220sf_launchxl), use overlay-tls-offload.conf instead of overlay-tls.conf.

The certificate used by the sample can be found in the sample’s src directory. The certificate was selected to enable access to the default website configured in the sample (https://google.com). To access a different web page over TLS, provide an appropriate certificate to authenticate to that web server.

Note, that TLS support in the sample depends on non-posix, TLS socket functionality. Therefore, it is only possible to run TLS in this sample on Zephyr.

Running application on POSIX Host

The same application source code can be built for a POSIX system, e.g. Linux. (Note: if you look at the source, you will see that the code is the same except the header files are different for Zephyr vs POSIX.)

To build for a host POSIX OS:

$ make -f Makefile.posix

To run:

$ ./http_get

As can be seen, the behavior of the application is the same as the Zephyr version.