... architecting & implementing help w/ Perl & REST - perl

Question

I really just need some basic software engineering architecting guidance... When I say 'architecting', I mean pseudo-code or statements I can go after in the Perl book I have, and hopefully some online examples...
I'm using Perl and I'm trying to parse Medline/Pubmed file paths on an Unix system in order to finally pass the PMID from each path to a pmid2doi conversion website (http://www.pmid2doi.org/).
The structure of each link is a filepath of the form...
/xxxxx/xxxxx/xxxxx/xxxxx/xxxxx/UNC00000000000042/00223468/v45i3/S0022346809003820
|<-PMID->|
where 00223468 is the PMID.
$ ls
18507872 main.pdf main.raw main.xml
So far, I've got something that looks like this (in bash):
for doi in `find . -name "*.xml" | awk -F\/ '{print $2}' ` #this extracts the PMID
do
echo $doi
wget pmid2doi website
done
Now I need help translating it to Perl.
The pmid2doi website requires inputting the PMID in order to get back the DOI.
This is what I need to get running in Perl, and I need a little help in designing implementing this...
Given your development background, I would be grateful for any insights, or recommended sites for generating regular expressions in Perl.
thanks very much!
Additionally:
I see that the pmid2doi website says the REST API expects the website plus the DOI value.
So I need to find some example Perl code that gets a REST value from a URL.
In REST I just prepare the URL as specified and then the returned result should be the value I want.

Answer 1

Something like this maybe?
use File::Find;
my $client = REST::Client->new( $an_url );
File::Find::find( sub {
return unless m/\.xml$/;
carp "Could not open $File::Find::name!"
unless open( my $fh, '<', $File::Find::name )
;
my $doi;
while ( <$fh> ) {
next unless ( $doi ) = m{[^/]*/([^/]*)};
$client->GET( join( '/', $base, $doi ));
do_stuff_with_content( $client->responseContent );
}
close $fh;
} => '.'
);

Answer 2

Am I misunderstanding things, or could you just do this in Perl locally and not bother with the website? No need to hit up a remote host and deal with latency, usage limits, etc...
https://metacpan.org/module/Bio::DB::EUtilities
Edit: I am, that's a CGI client for NCBI. From the docs: 'A separate project, currently present in BioPerl-Run, utilizes the SOAP-based interface for eUtils.'
https://bitbucket.org/reece/docdepot/src/ca32360f6fa4/archive/perl-version/bin/doi-to-pmid
#!/usr/bin/perl
# doi-to-pmid -- get the PubMed ids for a doi
use strict;
use warnings;
use Bio::DB::EUtilities;
my #pmids = doi_to_pmids( $ARGV[0] );
exit 1 unless (#pmids);
print( join("\n",#pmids), "\n" );
exit;
sub doi_to_pmids {
my $doi = $_[0];
my $f = Bio::DB::EUtilities->new(-eutil => 'esearch',
-db => 'pubmed',
-term => "$doi [doi]");
my #ids = $f->get_ids();
return (#ids);
}