Question

I’m writting a small server with perl. There is some small problem. When the client give me a sentence like this “op:xxx:xxx:xxx”, I’ll get op. then do things depending on what op is. It works will if the op is adduser and so on. (I use if $op eq “adduser”…)
But when I get a “getList:xxx:xxx” and I have get the $op = getList, it can’t pass it like “if $op eq “getList””. I know, it must be my mistake. But I just can’t find it.
thank you for everyone.

use warnings;
use strict;

package MyPackage;
use base qw(Net::Server);
our %data_base;
our %tag_base;
sub list {
    my %resault;
    foreach ( keys %tag_base) {
        print STDERR $_ . "1";
        my @tags = split /:/, $tag_base{$_};
        foreach ( @tags) {
            $resault{$_} ++;
        }
    }
    my @tags;
    foreach ( keys %resault) {
        push @tags, "$_,$resault{$_}";
    }
    $_ = join ";", @tags;
    print ;
    print STDERR ;
}

sub users {
    my $topic = shift;
    my @users;
    foreach ( keys %tag_base) {
        push @users, $_ if $tag_base{$_} =~ /$topic/;
    }
    $_ = join ";", @users;
    print ;
}

sub process_request {
    my $self = shift;
    my $person;
    my @info;
    while (<STDIN>) {
        my @gets = split /:/, $_;
        print STDERR "@gets\n";
        # $data_base{shift @person} = join ":", @person;
        my $op = shift @gets;
        $op =~ s/\s//;
        print STDERR $op . "\n";
        if (  $op eq "adduser") {
            my $user_name = shift @gets;
            if ( exists $data_base{$user_name}) {
                print "already_exist";
            } else {
                $data_base{$user_name} = join ":", @gets;
                print "addUserSu";
            }            
        } elsif ( $op eq "login") {
            my $login_name = shift @gets;
            my $login_pw   = shift @gets;
            if ( defined $data_base{$login_name}) {
                $person = $data_base{$login_name};
                @info   = split /:/, $person;
                $info[0] =~ s/\s+//;
                if ($login_pw eq $info[0]) {
                    print "$person";
                } else {
                    print "/$info[0]/";
                }
            } else {
                print "unexist_user";
            }
        } elsif ( $op eq "addTag") {
            my $tag_user = shift @gets;
            $tag_base{$tag_user} = join ":", @gets;
            print "addTagSu";
        } elsif ( $op eq "getList") {
            print STDERR "right";
            &list;
        } elsif ( $op eq "getUsers") {
            &users;
        }
    }
}

MyPackage->run(port => 13800);

Answer 1

I can see two (simple) reasons this might fail:

$op =~ s/\s//;

You only remove one whitespace: The first one. If your intention is to strip all whitespace, you’d want s/\s+//g.

And second:

Random capital letters in strings, variable names and commands is Evil. eq is case sensitive, so if $op is "getlist", then if ($op eq "getList") will be false. Unless capitalization is important to you, you could do if (lc($op) eq "getlist").

Without sample input, expected output and actual output, this is however nothing more than guesswork.

Also, as a debug statement, this is useless:

print STDERR $op . "\n";

That is easily confused and overlooked. For example, if $op is empty, it just produces a blank line in your error log. Use:

print STDERR "OP is: '$op'\n";

Now you will be able to identify the line where $op should appear, and you will be more easily see whitespace surrounding it.