Re: first cgi

by "Peter Newton" <c-newton(at)ihug.co.nz>
Date:	Tue, 22 Feb 2000 12:54:07 +1300
To:	<hwg-techniques(at)mail.hwg.org>
References:	SOWINSO
	todo: View Thread, Original
Hi Roger,

After youv'e picked up on the greate advice from Brian I'de like
 to add one more tip that I was shown from this list when I was
starting out with cgi/perl and thats this.

The error message you received is one that you will probably
see many times and it is quite frustrating especially when you
have a large script because it does not tell you WHAT went 
wrong. 

The system error logs is one way to find out but if you cannot
access them here is another:-

put the following code at the start of your script like so:-

#!/usr/bin/perl 
 
BEGIN {
open (STDERR, ">error.txt");      #redirect Error Messages to file
$localtime=localtime;                   #get local time/date
print STDERR "\n$localtime\n";  #time stamp error msgs
}

The rest of you script as normal

What this does is redirect the STDERR output to a file in this 
case called error.txt but you can call it whatever suits you. As 
perl processes your script it sends its error messages to 
STDERR which is now being conveniently stored into this file. 

So then when you get that error display again simply use your
WS ftp to read this file and it will tell you WHAT it found wrong 
even on what line number. 2ndly the line number it displays does
NOT take account of any line Wrapping so you may need to 
turn "word wrap" off in your text edditor if you can. 

NB.
You actually only need the 
open ( ..... etc  line the next 2 lines just put a time stamp into
the file which may be useful.  It does demonstrate another
live example of using localtime mentioned by Brian so I left it in.

I hope this saves you heaps of time.

Peter Newton




-----Original Message-----
From: Roger Harness [SMTP:muagic32(at)jps.net]
Sent: Monday, February 21, 2000 11:19 AM
To: hwg-techniques(at)mail.hwg.org
Subject: first cgi

Ok technique gurus, I have a question for you. I'm trying to do just a
basic cgi (script?). I'm using my "HTML 4 In a Week" book, along with the
tips from my hosting service. (hostsave.com, thank you Shelley!)

Using arachnophilia, I typed this:

#!/usr/bin/perl

echo Content-type: text/plain
echo

usr/bin/date

I saved this as getdate.cgi then uploaded it into my cgi-bin using WS_FTP
95 le as ASCII. That's correct, right??

I then made a basic html page called getthedate.html with this code:

<html>
<!-- Copyright (c) 2webslingers -->
<head>
<title>practice cgi</title>
</head>

<A href="http://www.2webslingers.com/cgi-bin/getdate.cgi">display the
date</A>
</body>
</html>


so when I click on "display the date" I *should* get today's date, correct?
(BTW, hostsave does NOT allow telnet, so I can't just go to the command
prompt and try typing date :)

Instead of today's date showing up, I get:

**********************************
Internal Server Error
The server encountered an internal error or misconfiguration and was unable
to complete your request.
Please contact the server administrator, webmaster(at)2webslingers.com and
inform them of the time the error occurred, and anything you might have
done that may have caused the error.

More information about this error may be available in the server error log.
**********************************

the server log doesn't give me any helpful info, and hostsave doesn't give
any tech support for cgi scripting.

Does anyone have any advice/suggestions here? I've used the cut and paste
FormMails before, and I can usually get stuff like that to work, but I'm
just not having any luck with this simple, stupid date thing. I've tried
just about everything (changing parts of code, where I put the files etc,
but no luck. Any help would be greatly appreciated!!!


Sincerely,

Roger Harness
HWG hwg-techniques mailing list archives, maintained by Webmasters @ IWA