abstraction layer to support both ZOOM and Net::Z3950

git-svn-id: svn://svn.open-ils.org/ILS/trunk@7365 dcc99617-32d9-48b4-a31d-7c20da2025e4

diff --git a/Open-ILS/src/perlmods/OpenILS/Utils/ZClient.pm b/Open-ILS/src/perlmods/OpenILS/Utils/ZClient.pm
new file mode 100644 (file)
index 0000000..db6407c
--- /dev/null
+++ b/Open-ILS/src/perlmods/OpenILS/Utils/ZClient.pm
@@ -0,0 +1,55 @@
+package OpenILS::Utils::ZClient;
+use UNIVERSAL::require;
+
+our $conn_class = 'ZOOM::Connection';
+our $imp_class = 'ZOOM';
+
+# Detect the installed z client, prefering ZOOM.
+if (!$imp_class->use()) {
+
+       $imp_class = 'Net::Z3950';  # Try Net::Z3950
+       if ($imp_class->use()) {
+
+               # Load the modules we're going to modify
+               'Net::Z3950::Connection'->use();
+               'Net::Z3950::ResultSet'->use();
+               'Net::Z3950::Record'->use();
+
+               # Tell 'new' how to build the connection
+               $conn_class = 'Net::Z3950::Connection';
+               
+               # Now we're going to give Net::Z3950 a ZOOM-ish interface
+
+               # Move 'record' out of the way ...
+               *{'Net::Z3950::ResultSet::_real_record'}  = *{'Net::Z3950::ResultSet::record'};
+               # ... and install a new version using the 0-based ZOOM semantics
+               *{'Net::Z3950::ResultSet::record'}  = sub { return shift()->_real_record(shift() - 1); };
+
+               # Alias 'search' with the ZOOM 'search_pqf' method
+               *{'Net::Z3950::Connection::search_pqf'}  = *{'Net::Z3950::Connection::search'};
+
+               # And finally, alias 'rawdata' with the ZOOM 'raw' method
+               *{'Net::Z3950::Record::raw'}  = sub { return shift()->rawdata(@_); }
+
+       } else {
+               die "Cannot load a z39.50 client implementation!  Please install either ZOOM or Net::Z3950.\n";
+       }
+}
+
+# 'new' is called thusly:
+#  my $conn = OpenILS::Utils::ZClient->new( $host, $port, databaseName => $db, user => $username )
+
+sub new {
+       my $class = shift();
+       my @args = @_;
+       if ($class ne __PACKAGE__) { # NOT called OO-ishly
+               # put the first param back if called like OpenILS::Utils::ZClient::new()
+               unshift @args, $class;
+       }
+
+       return $conn_class->new(@_);
+}
+
+
+1;
+