problem is posting variables in CGI script

girish_hilage · 05-03-2007, 08:56 AM

Hi,

I am wrinting one CGI script.
The HTML screen it creates has 2 elements on it (1 text box and 1 submit button).
In the "form" I am using POST method.

The problem is that, when I click on the submit button the variables for text box and the submit button are not getting posted.
I checked it by inserting the command "export > /tmp/environment" command in the CGI script that I am calling from the browser.
The variables that are supposed to be posted should be part of the environment and should appear in the file /tmp/environment. But
I could not find them in this file.

However, If I use GET method then I could see the variables and their values in the QUERY_STRING variable.

Can anybody suggest why this is happening and am I missing something here?

Regards,
Girish

acid_kewpie · 05-03-2007, 09:17 AM

not a networking question. moved to programming.

theNbomr · 05-03-2007, 09:34 AM

I belive that data transfer with the POST method is available to the CGI on its STDIN, not in the environment. Try reading STDIN, until eof().
--- rod.

girish_hilage · 05-04-2007, 02:04 AM

My script (test.cgi) is as follows :

#!/bin/bash

export > /tmp/environment
read -s arg1 arg2
echo "arg1=$arg1" > /tmp/args
echo "arg2=$arg2" >> /tmp/args

echo "Content-type: text/html"
echo ""
echo "<html>"
echo "<head>"
echo "<title>Test CGI!</title>"
echo "</head>"
echo "<body>"
echo "<form name=INPUT_FORM method=POST action=test.cgi>"
echo "Enter any text :"
echo "<input type=text name=text_box size=16>"
echo "<input type=submit value=OK name=submit_btn>"
echo "</form>"
echo "</body>"
echo "</html>"

exit 0

And I am getting following output in the file /tmp/args
arg1=text_box=hello+world&submit_btn=OK
arg2=

How can I get above values in separate variables?

bigearsbilly · 05-04-2007, 03:43 AM

the problem is, that the stdin comes in as one long line
like:

Code:

 text_box=hello&submit_btn=OK

but has no terminating linefeed, hence the read never
completes.

I would strongly advise maybe using perl's CGI module as it's much safer than trying yourself.
Still here is a solution of sorts...
(I've tidied up those horrible echoes

Code:

#!/bin/bash
cat <<EOF
Content-type: text/html

<html>
<head>
<title>Test CGI!</title>
</head>
<body>
<form name=INPUT_FORM method=POST action=test.cgi>
Enter any text :
<input type=text name=text_box size=16>
<input type=submit value=OK name=submit_btn>
</form>
EOF


IFS=\&          # ampersands that delimit parameter=value pairs
set -- `cat`    # a trick to assign pairs to $@ variables
for x;do
    var=${x%=*}
    val=${x#*=}
    echo "<p>$var is:$val</p>"
done




cat << EOF
</body>
</html>
EOF

exit 0

girish_hilage · 05-04-2007, 05:15 AM

Thanks for your reply. Its working fine. But I still think there is some other way by which we can directly read the values of the respective variables.

bigearsbilly · 05-04-2007, 05:27 AM

I think you are in for a disappointment

theNbomr · 05-04-2007, 09:28 AM

Quote:

Originally Posted by girish_hilage

Thanks for your reply. Its working fine. But I still think there is some other way by which we can directly read the values of the respective variables.

If you think about it, in your scenario, how could the second argument ever get read? If the argument list is separated by eofs, then only the first argument could ever get read. Alternatively, the argument list is separated by '&'s, which is left up to your code to interpret. When the data is a stream, you can only ever read it all, and then break it up as appropriate.

--- rod.

bigearsbilly · 05-04-2007, 10:07 AM

agreed.
if it's POST it's a line on stdin
if it's GET its in $QUERY_STRING

them's the rules, we don't make 'em.