Can't use string ("") as a HASH ref while "strict refs"

hesco has asked for the wisdom of the Perl Monks concerning the following question:

Hello all:

I'm working on an application which has outgrown its previous configuration arrangement. I'm now getting the following error, on the following line, which is calling the subroutine reproduced below.

How can I make this error go away and this script give me my database connection from the new configuration scheme? Why does it wait till the db_name to choke, while allowing the db_host_name to pass through without complaint?

-- Hugh

Software error:

Can't use string ("databasename ") as a HASH ref while "strict refs" in use at /usr/lib/cgi-bin/bc/supporters.cgi line 265.

(Yes, I see that I still need to strip that trailing space. That is a different issue, I think).

line 265 reads:

my $dbh = vol::connect_new($config{'db'}{qw(db_host_name db_name db_us
+er db_pw)});
[download]

that subroutine reads:

sub connect_new {
   my($host,$db,$user,$pw) = @_;
#   my $host = "$config{'db'}{'db_host_name'}";
#   my $db = "$config{'db'}{'db_name'}";
#   my $user = "$config{'db'}{'db_user'}";
#   my $pw = "$config{'db'}{'db_pw'}";
   my $dsn = "DBI:mysql:host=$host;database=$db";
   return (DBI->connect($dsn,$user,$pw,
      {PrintError => 0, RaiseError => 1}));
}
[download]

Comment on Can't use string ("") as a HASH ref while "strict refs" Select or Download Code

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Re: Can't use string ("") as a HASH ref while "strict refs" by bart (Canon) on Nov 26, 2005 at 00:13 UTC
`my $dbh = vol::connect_new($config{'db'}{qw(db_host_name db_name db_user db_pw)});` Hmm, in Perl, that is nonsense. Try something like `my $dbh = vol::connect_new(@{$config{'db'}}{qw(db_host_name db_name db +_user db_pw)});` [download] I can't seem to find anything else wrong with your code, at first sight, so let's just start by trying that out, will you?	[reply] [d/l] [select]
Re^2: Can't use string ("") as a HASH ref while "strict refs" by hesco (Deacon) on Nov 26, 2005 at 01:46 UTC
Bart: Thanks for that. It did not change the error message one iota. Here is the block that defines $config{'db'}. It parses a plain text config.db file which defines four connection variables (host, database, user, password). Similar blocks parse configuration parameters for different elements of the %config hash, which is returned with the Exporter with: `our %config;` [download] while (<DB>) { chomp; next if /^\s\#/; # Allow comments next if /^\s$/; # Allow blank lines unless (/=/) { # All other lines must look like: KEY + = VAL die "invalid variable assignment in supporters.db: $_"; } my ($key, $val) = split(/\s=\s/,$_,2); # Key and value are separ +ated by equals and maybe space $key =~ s/^\s//; # Strip any leading space from the key # $val =~ s/(\$(\w+))/$config{$2}/g; # Very simple (read: brittle) v +ariable interpolation $val =~ s/ $//g; # Strip trailing white space from value $config{'db'}{'$key'} = $val; } close DB; [download] should this be creating references, instead of simply hash elements? Sorry for delay in responding. I was interrupted by a customer here. Thanks for your help and insight.	[reply] [d/l] [select]
Re^3: Can't use string ("") as a HASH ref while "strict refs" by ikegami (Patriarch) on Nov 26, 2005 at 03:27 UTC
`$config{'db'}{'$key'} = $val;` should be `$config{'db'}{$key} = $val;` but I don't think that will fix your error. The error seems to indicate that `$config{'db'}` was assigned `''` or `undef`. Are you sure both `%config` are the same variable?	[reply] [d/l] [select]
Re^4: Can't use string ("") as a HASH ref while "strict refs" by hesco (Deacon) on Nov 26, 2005 at 05:08 UTC
Re^5: Can't use string ("") as a HASH ref while "strict refs" by ikegami (Patriarch) on Nov 26, 2005 at 05:15 UTC
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Re^3: Can't use string ("") as a HASH ref while "strict refs" by bart (Canon) on Nov 26, 2005 at 09:16 UTC
Ugh! You're using `%config` both as input, for "variable values", thus containing strings. as for the output, in `$config{'db'}`, as a hash ref. My gut feeling tells me this, or something very similar, is the cause of your problem. You may have tried to use `$config{'db'}` as a string value first, which could well cause your problem. Just put your input and output in different variables.	[reply] [d/l] [select]
Re: Can't use string ("") as a HASH ref while "strict refs" by bradcathey (Prior) on Nov 26, 2005 at 00:01 UTC
You didn't show the actual values, but I would imagine you have an escape issue. —Brad "The important work of moving the world forward does not wait to be done by perfect men." George Eliot	[reply]