NAME

       Frontier::Responder - Create XML-RPC listeners for normal CGI processes

SYNOPSIS

        use Frontier::Responder;
        my $res = Frontier::Responder->new( methods => {
                                                        add => sub{ $_[0] + $_[1] },
                                                        cat => sub{ $_[0] . $_[1] },
                                                       },
                                           );
        print $res->answer;

DESCRIPTION

       Use Frontier::Responder whenever you need to create an XML-RPC listener using a standard
       CGI interface. To be effective, a script using this class will often have to be put a
       directory from which a web server is authorized to execute CGI programs. An XML-RPC
       listener using this library will be implementing the API of a particular XML-RPC
       application. Each remote procedure listed in the API of the user defined application will
       correspond to a hash key that is defined in the "new" method of a Frontier::Responder
       object. This is exactly the way Frontier::Daemon works as well.  In order to process the
       request and get the response, the "answer" method is needed. Its return value is XML ready
       for printing.

       For those new to XML-RPC, here is a brief description of this protocol.  XML-RPC is a way
       to execute functions on a different machine. Both the client's request and listeners
       response are wrapped up in XML and sent over HTTP. Because the XML-RPC conversation is in
       XML, the implementation languages of the server (here called a listener), and the client
       can be different. This can be a powerful and simple way to have very different platforms
       work together without acrimony. Implicit in the use of XML-RPC is a contract or API that
       an XML-RPC listener implements and an XML-RPC client calls. The API needs to list not only
       the various procedures that can be called, but also the XML-RPC datatypes expected for
       input and output. Remember that although Perl is permissive about datatyping, other
       languages are not. Unforuntately, the XML-RPC spec doesn't say how to document the API. It
       is recommended that the author of a Perl XML-RPC listener should at least use POD to
       explain the API.  This allows for the programmatic generation of a clean web page.

METHODS

       new( OPTIONS )
           This is the class constructor. As is traditional, it returns a blessed reference to a
           Frontier::Responder object. It expects arguments to be given like a hash (Perl's named
           parameter mechanism).  To be effective, populate the "methods" parameter with a
           hashref that has API procedure names as keys and subroutine references as values. See
           the SYNOPSIS for a sample usage.

       answer()
           In order to parse the request and execute the procedure, this method must be called.
           It returns a XML string that contains the procedure's response. In a typical CGI
           program, this string will simply be printed to STDOUT.

SEE ALSO

       perl(1), Frontier::RPC2(3)

       <http://www.scripting.com/frontier5/xml/code/rpc.html>

AUTHOR

       Ken MacLeod <ken@bitsko.slc.ut.us> wrote the underlying RPC library.

       Joe Johnston <jjohn@cs.umb.edu> wrote an adaptation of the Frontier::Daemon class to
       create this CGI XML-RPC listener class.