=head1 NAME

PLP::HowTo - Some examples of common web things in PLP.

=head1 HOW TO...

Additional Perl functionality is often available in modules. All of the modules
used in this document are available (for free) at CPAN: http://search.cpan.org/

=head2 send a cookie

 <: 
     BEGIN {
	 use CGI::Cookie;
	 AddCookie(
	     CGI::Cookie->new(
		 -name => 'ID',
		 -value => 123456,
		 -domain => 'foo.com',
		 -path => '/'
	     )->as_string
	 );
     }
 :>

=head2 get a cookie

 Your user ID is <:= $cookie{ID} :>

=head2 set a header

 <:
     BEGIN {
         $header{Content_Type} = 'text/plain';
     }
 :>

=head2 use a database

Use DBI, and alternatively, one of the many simplifying modules. Drivers for
DBI are in the DBD:: namespace. DBI loads the driver automatically, but it has
to be available. If you need a fast full-featured file-base database, use
DBD::SQLite, it's the instant database :).

 <:
     use DBIx::Simple; # and read its documentation for examples.
 :>

=head2 allow a user to upload a file

Use CGI.pm, which can be used with CGI::Upload to make things easier

 <:
     use CGI;         # and don't use %post in your PLP document.
     use CGI::Upload; # and read its documentation for examples.
     my $cgi = CGI->new;
     my $upload = CGI::Upload->new($cgi);
     ...
 :>

=head2 download a file into a variable

 <:
     use LWP::Simple;
     my $page = get 'http://foo.com/bar.html';
 :>

=head2 implement basic authentication

This only works with PLP under mod_perl. For CGI installations, it's useless.

 <:
     use MIME::Base64;

     BEGIN {
         my $r = Apache->request;

         my ($type, $login) = split / /, $r->header_in('Authorization');
         my ($user, $pass) = split /:/, decode_base64 $login, 2;

         unless ($user eq 'foo' and $pass eq 'bar') {
             $header{Status} = '401 Authorization Required';
             $header{WWW_Authenticate} = 'Basic realm="Top secret :)"';
             print '<h1>Authorization Required</h1>';
             exit;
         }
     }
 :>

(It is possible to use something similar with CGI, but it's not easy. Headers
are communicated to your script via C<%ENV>, and having credentials in there
would be insecure, so Apache removes them. To get C<$ENV{HTTP_AUTHORIZATION}>,
you need to recompile Apache with -DSECURITY_HOLE_PASS_AUTHORIZATION, or use
mod_rewrite to set the environment variable. Short answer: just use mod_perl.)

=head1 FEEDBACK

If you have good, simple examples of how to do common things with PLP, please
send them! <perl@shiar.org>

=cut