Hello Word in CGI

Thu Jul 6 13:50:54 EDT 2000

Bjorn Pettersen wrote:
> 
> Curtis Jensen wrote:
> >
> > Bjorn Pettersen wrote:
> > >
> > > What you're seeing are the symptoms of Python having thrown an exception
> > > and the weblog not capturing all the information. The solution is to make
> > > sure Python can only throw where you can grab the exception and do
> > > something useful with it, like printing it to the browser...  Try the
> > > following (but make sure you can execute it from the command line first --
> > > one possible error is a SyntaxError, which this scheme will not save you
> > > from...)
> > >
> > > -- bjorn
> > >
> > > #!/usr/bin/env python
> > > print """Content-type: text/html
> > >
> > > """
> > >
> > > def main():
> > >     from time import *
> > >
> > >     print "<HTML>"
> > >     print "<Head>"
> > >     print "<Title>Hello World</Title>"
> > >     print "</Head>"
> > >     print "<Body>"
> > >     print "<H1>Hello World !</H1>"
> > >     print "<hr>"
> > >     print "<P>This is San Diego.<br>Localtime is", ctime( time() ) + ".<P>"
> > >
> > >     print "</Body>"
> > >     print "</HTML>"
> > >
> > > import traceback
> > >
> > > def execute(fn):
> > >     # make sure any errors are legible, and directed to the user.
> > >     try:
> > >         sys.stderr = sys.stdout
> > >         fn()
> > >     except:
> > >         print '<h1>Something went wrong!!!</h1>'
> > >         print 'Please send the transcript below to webmaster at your.web<p>'
> > >         print '\n\n<pre>'
> > >         traceback.print_exc()
> > >
> > > execute(main)
> > >
> >
> > I tried this.  I got the same errors in the log and in the browser.  I
> > took out the print line since it caused a discussion.  Any more
> > suggestions?  Thanks.
> 
> You do need the print line! The first thing your cgi must print out
> (modulo cookies) is "Content-type: text/html" followed by exactly two
> newlines (yes, I know there are situations where this isn't true, but in
> this case it is.. <wink>)

Sorry, I didn't say witch line.  I took out the print line with the time
in it.  So now it is a simple hello world script.  By the way, is,
print 'Content-type: text/html\n\n'
just as good as they way you have it?  I've tried both.

> 
> Check that:
> 
>  - your script is executable (by everyone)

It is. permissions are 775

>  - some webservers require a .cgi extension (a symbolic link to your .py
> will work)

I tried that and got the same errors

>  - python is where you think it is, and is executable (again by
> everyone)

from the unix prompt, I can run helloworld.py and it prints fine. 
Permissions on python are 755

>  - your webserver is set up to execute cgi scripts.

In the same directory as helloword.py there are Pearl cgi scripts that
run fine.

> If all that works, try the simplest possible cgi script, something like:
> 
> #!/usr/local/bin/python
> print  """Content-type: text/html
> 
> """
> print '<h1>hello world</h1>'

We tried this and got the same problem.
Anything else?  Thanks for the help so far.

-- 
Curtis Jensen
cjensen at bioeng.ucsd.edu
http://www-bioeng.ucsd.edu/~cjensen/
FAX (425) 740-1451