Add HTTP client examples

[peterharperuk]

Examples to demonstrate HTTP, HTTPS and TLS validation Uses the lwip HTTP client

Fixes #318

[peterharperuk]

Needs raspberrypi/pico-sdk#1388

[lurch]

I guess this PR should probably update https://github.com/raspberrypi/pico-examples/blob/develop/README.md too?

EDIT: done

[peterharperuk]

Depends on #460

[lurch]

Should this be "rebased" on top of #475 , or will #475 get updated after this PR has been merged? (or am I barking up entirely the wrong tree? 😆 )

[peterharperuk]

Oops, yes you're right. I'll fix that. GitHub doesn't seem to handle dependencies between PR's but I can assume it's merged first

[hasenradball]

@peterharperuk
Hi Peter,

got some error during compile.
missing some file.

[build]                  from /home/frank/Dokumente/Pi_Pico_C++_SDK/pico/pico-examples/pico_w/wifi/http_client/picow_http_client.c:11:
[build] /home/frank/Dokumente/Pi_Pico_C++_SDK/pico/pico-examples/pico_w/wifi/http_client/mbedtls_config.h:4:10: fatal error: mbedtls_config_examples_common.h: No such file or directory
[build]     4 | #include "mbedtls_config_examples_common.h"
[build]       |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[peterharperuk]

It needs to be rebased on the tip of develop where that file exists. I've done this and pushed an update with conflicts resolved.

[hasenradball]

@peterharperuk
Hi Peter,

some hint to your example I would add the LEDas indicator to show if test is active or finished.

• Just switch on LED at beginning.

• Switch off when test is passed.

• Maybee let led blink when no connection is possible.

So you see directly at the LED whats going on.

[lurch]

I think that this example (like all the other examples in this repo) assumes that you're able to see the printf outputs. See Chapter 4 of https://datasheets.raspberrypi.com/pico/getting-started-with-pico.pdf

[peterharperuk]

I also think this would be confusing as the example gives you the ability to switch the led on and off.