Raspberry pi Webserver handling Get Requests

Question

So I have an apache webserver running on my pi. It's pretty basic right now but that's what I need help with. I have another device, an arduino, that is going to make http requests to the pi's webserver. The Http Request from the arduino goes like

GET test.php HTTP/1.1
Host: 192.168.1.23

How do I write code on the server side to handle such a request (with more headers in the future) and then return an one or two word response?

Thanks!

Answer 1

Are you familiar with PHP? If I were you, for the sake of testing, I'd run PHP's bundled webserver. The following bash:

$ php -S localhost:8000 -t folder_with_php_files/

will start PHP's bundled web server at port 8000, so from your other machine, you could do the following to make a request to the PHP server (assuming Rasp Pi's internal address is at 192.168.1.23):

$ curl "192.168.1.23:8000/request_handler.php?query=Hello+world"

To conclude, if you had a request_handler.php with the following code:

<?php
echo "You said {$_GET['query']}\n";
?>

cURL would return:

"You said [whatever you send it]". 

I think this is good to get to know the basics. You probably already have cURL installed on your system (assuming we're talking about *nix), but if not, you should consult your distribution's cURL package (you can Google "[my distribution] cURL install". For instance, for Debian family, you'd do:

$ apt-get install curl

If you encounter problems, feel free to post comments. The most common problem could be the inability of your internal networks's computers to be unable to communicate with each other(firewalls), so use ping to test it out.