Foray into CGI

by **Charles** » Sat Apr 11, 2009 5:31 pm

I made an attempt at creating .cgi scripts in Cobra on a Linux box with Apache. It ultimately failed, but I wanted to record my steps here and possibly get ideas from others.

First, I added this config in Apache's httpd.conf for a particular directory:

Code: Select all: Options Indexes FollowSymLinks Includes +ExecCGI AddHandler cgi-script cgi

Then I got a "python.cgi" script working to verify that CGI worked:

Code: Select all: #!/usr/bin/python import time stamp = time.asctime() print 'Content-Type: text/html\r\n\r\n' print '<html>' print '<body>Hello from Python at %s</body>' % stamp print '</body>'

There was no binary install of Novell Mono for my distro, so I grabbed the Mono 2.4 source tarball and did:

Code: Select all: ./configure --prefix=/usr/local make make check make install

Which went fine. I then installed the last Cobra release (2009-04-07) and attempted the same type of CGI script with Cobra:

#!/usr/local/bin/cobra

class X

        def main is shared
                print 'Content-Type: text/html\r\n\r\n'
                print '<html>'
                print '<body>Hello from Cobra at [DateTime.now]</body>'
                print '</body>'

This failed. It even failed to run at the command line with "./cobra-test.cgi" where almost every line generated an error, but not one from the Cobra compiler. Execution perms and file ownership were correct. Since it looked like bash was trying to read the source, I read the wikipedia page on shebang and discovered that the shebang line cannot point to another script. The "cobra" command is another script. But they say you can do this:

#!/usr/bin/env /usr/local/bin/cobra

...and indeed that works from the command line.

It failed as a .cgi script though and the error log complained that "mono" could not be found. So I changed the "cobra" script to use the full path to mono:

Code: Select all: #!/bin/bash exec /usr/local/bin/mono "/usr/local/cobra/Cobra-0.8.0-post-2009-04-07/bin/cobra.exe" "$@"

That worked which got me to the next error:

Code: Select all: [Sat Apr 11 17:31:12 2009] [error] [client 66.171.254.110] [Sat Apr 11 17:31:12 2009] [error] [client 66.171.254.110] GThread-ERROR **: file gthread-posix.c: line 135 (): error 'Operation not permitted' during 'pthread_getschedparam (pthread_self(), &policy, &sched)' [Sat Apr 11 17:31:12 2009] [error] [client 66.171.254.110] aborting... [Sat Apr 11 17:31:12 2009] [error] [client 66.171.254.110] Premature end of script headers: cobra-test.cgi

Here is another script that cuts Cobra out. It works at the command line but chokes in Apache with the same GThread-ERROR:

Code: Select all: #!/bin/bash echo 'Content-Type: text/html' echo '' /usr/local/bin/mono

I'll check with the Mono discussion forums and see if they have anything to say.

by **Charles** » Sat Apr 11, 2009 6:04 pm

Omar at Arimaa.com reports that he was able to get .cgi installed easily. His approach is to make the .cgi script very small:

Code: Select all: #!/usr/local/bin/mono foo.exe

and put all the code in "foo.cobra".

Still doesn't work for me due to the aforementioned problem with running mono from cgi, but now it becomes clear that my problem is not a general one.

Foray into CGI

Foray into CGI

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