Programming the Perl DBI

Connecting to the proxy server

Now that we have configured our proxy server to sit and wait on port 3333 on our Windows machine, we need to tell the client Perl program on the Unix machine to use that proxy server instead of attempting to make a direct database connection itself.

For example, the ODBC test script above connects directly via the DBD::ODBC module with the following DBI->connect( ) call:

$dbh = DBI->connect( "dbi:ODBC:archaeo", "username", "password" );

This is fine for local connections, but how do we translate that into something the proxy server can use?

DBD::Proxy makes liberal use of the optional arguments that can be added to a DSN when specifying which database to connect to. DBD::Proxy allows you to specify the hostname of the machine upon which the proxy server is running, the port number that the proxy server is listening to, and the data source of the database that you wish the proxy server to connect to.

Therefore, to connect to the ODBC database called archaeo on the Windows machine fowliswester with a proxy server running on port 3333, you should use the following DBI- >connect( ) syntax:

$dsn   = "dbi:ODBC:archaeo";
$proxy = "hostname=fowliswester;port=3333";
$dbh = DBI->connect( "dbi:Proxy:$proxy;dsn=$dsn", '', '' );

This looks quite long-winded, but it’s a very compact and portable way to make a pass-through connection to a remote database by proxy.

Once you have connected to the proxy server and it connects to the desired data source, a valid database handle ...