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


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

send a cookie

     BEGIN {
         use CGI::Cookie;
                 -name => 'ID',
                 -value => 123456,
                 -domain => '',
                 -path => '/'

get a cookie

 Your user ID is <:= $cookie{ID} :>

set a header

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

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.

allow a user to upload a file

Use, 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);

download a file into a variable

     use LWP::Simple;
     my $page = get '';

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>';

(It is possible to use something similar with CGI, but it's not easy. Headers are communicated to your script via %ENV, and having credentials in there would be insecure, so Apache removes them. To get $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.)


If you have good, simple examples of how to do common things with PLP, please send them!