[Chicago-talk] Perl is telling me a HASH ref is saying a defined HASH ref ins undefined

[Alan Mead]

Richard,

Does defined() do what you want? I think you might want line 113 to be:

if (! *exists* $imap->parse_headers($msg,"Subject")->{"Subject"} || ! 
*exists* $imap->parse_headers($msg,"Subject")->{"Subject"}->[0] || ! 
defined $imap->parse_headers($msg,"Subject")->{"Subject"}->[0]) {

I have been surprised by what I think is called autovivication. I could 
also well be wrong about this.

-Alan

On 6/21/2023 9:22 AM, Richard Reina wrote:
> With the code below I use Perl to search through old email with a given title before or after a certain date and delete them. I invoke it like this: perl -e 'use RIMAPtools; my ($IMLU_obj) = RIMAPtools->new(since => "17-Nov-2020", username => "richard",  domain => "rushlogistics.com", sub_stg => "NETWORK STATUS REPORT"); $IMLU_obj->look_up();'
>
> Periodically the program crashes with error message: Can't use an undefined value as a HASH reference at /etc/perl/RIMAPtools.pm line 120.
>
>    LINE 113:     if (! defined $imap->parse_headers($msg,"Subject")->{"Subject"}->[0]) {
>    LINE 114:
>    LINE 115:           print "msg SUBJECT was not defined. Skipping to next email.\n";
>    LINE 116:           next;
>    LINE 117:
>    LINE 118:       } else {
>    LINE 119:
>    LINE 120:            $msg_subject = $imap->parse_headers($msg,"Subject")->{"Subject"}->[0];
>    LINE 121:
>    LINE 122:       }
>
>
> As you can see Perl tells me $imap->parse_headers($msg,"Subject")->{"Subject"}->[0] is defined on line 113 and then undefined on line 120. Any ideas?
>
> Full subroutine below.
>
> Thanks,
>
> Richard
>
> ##################
> sub look_up {
> ##################
>
>       my ( $self, %args ) = @_;
>      
>       my ($svr, $pw) = get_cred($self->{_username}, $self->{_domain});
>
>       print "Contacting: $svr vial Mail::IMAPClient.\n";
>
>       my $userid =  $self->{_username} . '@' . $self->{_domain};
>       
>       my $imap=Mail::IMAPClient->new(
>
>       Server => $svr,
>       Port => 143,
>       User => $userid,
>       Password => $pw,
>       Peek => 1,
>       
>      );
>       
>      unless($imap) {
>      
>      die "Couldn't log in to server: $svr $@\n";
>
>      }
>      
>      # Open the inbox
>      $imap->select('INBOX');
>      my @mails;
>      
>      if ($self->{_since}) {
>
>      print "Will look at messages before: $self->{_since}\n";
>      @mails = $imap->since($self->{_since}) or die "Could not find any messages since $self->{_since}: $@\n";
>
>      } elsif ($self->{_before}) {
>
>      print "Will look at messages before: $self->{_before}\n";
>      @mails = $imap->before($self->{_before}) or die "Could not find any messages before $self->{_before}: $@\n";
>      
>      }
>
>       if ($self->{_sub_stg}) {
>
>       print "Will search for mails with subject containing: $self->{_sub_stg}\n";
>
>      }
>       
>      foreach my $msg (@mails) {
>
>      my $msg_subject;
>
>      if (! defined $msg) {
>
>          print "msg was not defined. Skipping to next email.\n";
>          next;
>      }
>
>      if (! defined $imap->parse_headers($msg,"Subject")->{"Subject"}->[0]) {
>
>          print "msg SUBJECT was not defined. Skipping to next email.\n";
>          next;
>
>      } else {
>          
>          $msg_subject = $imap->parse_headers($msg,"Subject")->{"Subject"}->[0];
>
>      }
>      
>      if ($self->{_sub_stg}) {
>          
>          print "Will look for string: " . $self->{_sub_stg} . " IN SUBJECT: " . $msg_subject . "\n";
>          
>          if ($msg_subject =~ /$self->{_sub_stg}/) {
>          
>          print "MATCH: " . $msg_subject . " DATE: " . $imap->get_header($msg,"Date") . "\n";
>          $imap->delete_message($msg) or die "Could not delete_message: $@\n";;
>                      
>      }
>          
>      } # eo foreach
>      
> #######################
> } #EOS look_up
> #######################
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-- 

Alan D. Mead, Ph.D.
President, Talent Algorithms Inc.

science + technology = better workers

https://talalg.com


The reasonable man adapts himself to the world: the unreasonable one
persists in trying to adapt the world to himself. Therefore all progress
depends on the unreasonable man.

-- Shaw, from "Maxims for Revolutionists"

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