How do I access a hash from another subroutine? - perl

Question

I am trying to create some scripts for web testing and I use the following piece of code to set up variables from a config file:
package setVariables;
sub readConfig{
open(FH, "workflows.config") or die $!;
while(<FH>)
{
($s_var, $s_val) = split("=", $_);
chomp($s_var);
chomp($s_val);
$args{$s_var} = $s_val;
print "set $s_var = $s_val\n";
}
close(FH);
}
for example: var1=val1
var2=val2
var3=val3
etc...
I want to be able to pass the values set by this subroutine to a subroutine in another package. This is what I have for the package I want it passed into.
package startTest;
use setVariables;
sub startTest{
my %args = %setVariables::args;
my $s_var = $setVariables::s_var;
my $s_val = $setVariables::s_var;
setVariables::readConfig(); #runs the readConfig sub to set variables
my $sel = Test::WWW::Selenium->new( host => "localhost",
port => 4444,
browser => $args{"browser"},
browser_url => $args{"url"} );
$sel->open_ok("/index.aspx");
$sel->set_speed($args{"speed"});
$sel->type_ok("userid", $args{"usrname"});
$sel->type_ok("password", $args{"passwd"});
$sel->click_ok("//button[\#value='Submit']");
$sel->wait_for_page_to_load_ok("30000");
sleep($args{"sleep"});
}
Unfortunately its not holding on to the variables as is and I don't know how to reference them.
Thank you for any help.

Answer 1

Your code has some problems. Let's fix those first.
# Package names should start with upper case unless they are pragmas.
package SetVariables;
# Do this EVERYWHERE. It will save you hours of debugging.
use strict;
use warnings;
sub readConfig{
# Use the three argument form of open()
open( my $fh, '<', "workflows.config")
or die "Error opening config file: $!\n";
my %config;
# Use an explicit variable rather than $_
while( my $line = <$fh> )
{
chomp $line; # One chomp of the line is sufficient.
($s_var, $s_val) = split "=", $line;
$config{$s_var} = $s_val;
print "set $s_var = $s_val\n";
}
close $fh;
return \%config;
}
Then use like so:
use SetVariables;
my $config = SetVariables::readConfig();
print "$_ is $config->{$_}\n"
for keys %$config;
But rather than do all this yourself, check out the many, many config file modules on CPAN. Consider Config::Any, Config::IniFiles, Config::JSON.
You note in your comment that you are trying to work with multiple files, your main code and a couple of packages.
One pattern that is common is to load your config in your main code and pass it (or select elements of it) to consuming code:
package LoadConfig;
sub read_config {
my $file = shift;
my $config;
# Do stuff to read a file into your config object;
return $config;
}
1;
Meanwhile in another file:
package DoStuff;
sub run_some_tests {
my $foo = shift;
my $bar = shift;
# Do stuff here
return;
}
sub do_junk {
my $config;
my $foo = $config->{foo};
# Do junk
return;
}
1;
And in your main script:
use DoStuff;
use LoadConfig;
my $config = LoadConfig::read_config('my_config_file.cfg');
run_some_tests( $config->{foo}, $config->{bar} );
do_junk( $config );
So in run_some_tests() I extract a couple elements from the config and pass them in individually. In do_junk() I just pass in the whole config variable.

Answer 2

Are your users going to see the configuration file or just programmers? If it's just programmers, put your configuration in a Perl module, then use use to import it.
The only reason to use a configuration file for only programmers if you are compiling the program. Since Perl programs are scripts, don't bother with the overhead of parsing a configuration file; just do it as Perl.
Unless it's for your users and its format is simpler than Perl.
PS: There's already a module called Config. Call yours My_config and load it like this:
use FindBin '$RealBin';
use lib $RealBin;
use My_config;
See:
perldoc FindBin
perldoc Config

Answer 3

I would suggest using a regular format, such as YAML, to store the configuration data. You can then use YAML::LoadFile to read back a hash reference of the configuration data and then use it.
Alternatively, if you don't want to use YAML or some other configuration format with pre-written modules, you'll need for your reading routine to actually return either a hash or a a hashref.
If you need some more background information, check out perlref, perlreftut and perlintro.

Answer 4

all you need to do is collect the variable in a hash and return a reference to it in readConfig:
my %vars = ( var1 => val1,
var2 => val2,
var3 => val3,
);
return \%vars;
and in startTest:
my $set_vars = setVariables::readConfig();