Re: undefined value as filehandle from Curl.pm

The error is because you are not testing your open.

When opening a file, it's seldom a good idea to continue if the request failed, so open is frequently used with die. Even if die won't do what you want (say, in a CGI script, where you want to format a suitable error message (but there are modules that can help with that problem)) always check the return value from opening a file.

Changing line 234 to

open( my $fileb, ">", \$content ) or die "$!";
[download]

should be informative.

#11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.

Comment on Re: undefined value as filehandle from Curl.pm Download Code

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Re^2: undefined value as filehandle from Curl.pm by stevieb (Canon) on Jun 28, 2016 at 14:52 UTC
That's not the OP's code. That's code in the LWP::Curl module itself: LWP::Curl line 234. Also, that open should never technically fail, as the file (`$content`) is declared on the immediate line above. However, it should still be checked, even if out of habit alone, as perhaps corrupt/lack of memory or other oddness can still prevent the open.	[reply] [d/l]
Re^3: undefined value as filehandle from Curl.pm by Anonymous Monk on Jun 28, 2016 at 17:36 UTC
as perhaps corrupt/lack of memory or other oddness can still prevent the open. :) if it failed, wouldn't writing to the filehandle fail also?	[reply]
Re^4: undefined value as filehandle from Curl.pm by Marshall (Canon) on Jun 30, 2016 at 16:34 UTC
Yes, writing to an unopened file handle will result in the run time warning like this: `print() on unopened filehandle OUT at C:\Projects_Perl\testing\junk.pl line 11.` The code keeps going. Normally what is desired is to "die" when the open fails as something presumably very important didn't happen. If you check the status of the open with an "or die", you also get the line number of where this failure occurred. Try it yourself... `#!/usr/bin/perl use strict; use warnings; print OUT "something"; print "I kept going"; __END__ Name "main::OUT" used only once: possible typo at C:\Projects_Perl\tes +ting\testopenfailure.pl line 5. print() on unopened filehandle OUT at C:\Projects_Perl\testing\testope +nfailure.pl line 5. I kept going Process completed successfully` [download]	[reply] [d/l] [select]
Re^2: undefined value as filehandle from Curl.pm by wanderedinn (Sexton) on Jun 28, 2016 at 14:58 UTC
The `open()` you refer to is not in my code, it's in the perl module. I agree the success/failure of the `open()` should be tested.	[reply] [d/l] [select]
Re^3: undefined value as filehandle from Curl.pm by wanderedinn (Sexton) on Jun 29, 2016 at 14:20 UTC
So, here is an oddity. If I remove the following line: `$lwpcurl->{agent}->setopt( CURLOPT_HEADERDATA, ['Content-Type:text/xml +'] );` [download] The error: Can't use an undefined value as filehandle reference at /home/mware/httppost/lib/perl5/site_perl/5.8.8/LWP/Curl.pm line 236. Goes away. Although, the http post still does not work properly. I'm not seeing my test file on the server. I have a curl command line test that works correctly, but can not seem to configure the perl code to do the same.	[reply] [d/l]
Re^4: undefined value as filehandle from Curl.pm by wanderedinn (Sexton) on Jun 30, 2016 at 20:12 UTC
I have determined why this error was caused in this code. That is because the parameter I am attempting to use, expects a pointer to a file, file handle, rather than a string as I was attempting. Hence the reason for the filehandle error. Thought I'd post an update for others who might attempt to use this module.	[reply]