NAME

Apache::PageKit - Application framework using mod_perl and HTML::Template

SYNOPSIS

In httpd.conf

SetHandler perl-script
PerlSetVar PKIT_ROOT /path/to/pagekit/files

PerlHandler +Apache::PageKit
<Perl>
      Apache::PageKit->startup("/path/to/pagekit/files");
</Perl>

In MyPageKit/Common.pm

  package MyPageKit::Common;

  use base 'Apache::PageKit::Model';

  sub pkit_dbi_connect {
    return DBI->connect("DBI:mysql:db","user","passwd");
  }

  sub pkit_session_setup {
    my $model = shift;
    my $dbh = $model->dbh;
    return {
	session_lock_class => 'MySQL',
	session_store_class => 'MySQL',
	session_args => {
			Handle => $dbh,
			LockHandle => $dbh,
			},
	};
  }

  sub pkit_auth_credential {
    my ($model) = @_;

    # in this example, login and passwd are the names of the credential fields
    my $login = $model->input_param('login');
    my $passwd = $model->input_param('passwd');

    # create a session key
    # your code here.........

    return $ses_key;
  }

  sub pkit_auth_session_key {
    my ($model, $ses_key) = @_;

    # check whether $ses_key is valid, if so return user id in $user_id
    # your code here.........

    return $ok ? $user_id : undef;
  }

DESCRIPTION

PageKit is an mod_perl based application framework that uses HTML::Template and XML to separate code, design, and content. Includes session management, authentication, form validation, co-branding, and a content management system.

Its goal is to solve all the common problems of web programming, and to make the creation and maintenance of dynamic web sites fast, easy and enjoyable.

You have to write a module named MyPageKit::Common that inherits from Apache::PageKit::Model and provides methods common across the site. For example, if you wish to support authentication, it must include the two methods pkit_auth_credential and pkit_auth_session_key.

For more information, visit http://www.pagekit.org/ or http://sourceforge.net/projects/pagekit/

OBJECTS

Each $pk object contains the following objects:

$pk->{apr}

An Apache::Request object. This gets the request parameters and can also be used to set the default values in HTML form when fill_in_form is set.

$pk->{config}

An Apache::PageKit::Config object, which loads and accesses global, server and page attributes.

$pk->{model}

An MyPageKit::Common class object, derived from Apache::PageKit::Model.

$pk->{session}

Returns a reference to a hash tied to Apache::PageKit::Session.

$pk->{view}

An Apache::PageKit::View object, which interfaces with the HTML::Template templates.

Features

Model/View/Content/Controller approach to design

The Model is the user provided classes, which encapsulate the business logic behind the web site.

The View is a set of HTML::Template templates. Apache::PageKit::View acts as a bridge between the templates and the controller.

The Content is stored in XML files in the Content/xml directory. You may also store the content in the HTML::Template templates, if you don't need to seperate the View from the Content.

The Controller is a subclass of Apache::PageKit, which reads the client request, accesses the back end, and uses Apache::PageKit::View to fill in the data needed by the templates.

Seperation of Perl from HTML

By using HTML::Template, this application enforces an important divide - design and programming. Designers can edit HTML without having to deal with any Perl, while programmers can edit the Perl code with having to deal with any HTML.

Seperation of Content from Design with XML

By using the <CONTENT_VAR> and <CONTENT_LOOP> elements, you can autofill the corresponding <CONTENT_VAR> and <CONTENT_LOOP> tags in the template.

This is an easy way of using XML with HTML::Template that doesn't require the use of stylesheets.

Page based attributes

The attributes of each Page are stored in the Config/Config.xml file. This makes it easy to change Pages across the site. Apache::PageKit::Config provides a wrapper around this XML file.

For example, to require a login for a page, all you have to do is change the require_login attribute of the XML <PAGE> tag to yes, instead of modifying the Perl code or moving the script to a protected directory.

Automatic Dispatching of URIs

Apache::PageKit translates $r->uri into a class and method in the user provided classes. In the example in the synopsis, the URI /account/update will map to MyPageKit::PageCode::account->page_update.

Easy error handling.

Both warnings and fatal errors can be displayed on the screen for easy debugging in a development environment, or e-mailed to the site adminstrator in a production environment, as specified in the Apache ServerAdmin configuration directive.

You have to require Apache::PageKit::Error to turn on error handling.

Session Management

Provides easy access to a hash tied to Apache::PageKit::Session.

Authentication

Restricts access to pages based on the require_login attribute. If require_login is set to recent, then PageKit requires that session is currently active in the last recent_login_timeout seconds.

Form Validation

Uses HTML::FormValidator to provide easy form validation. Highlights fields in red that user filled incorrectly by using the <PKIT_ERRORFONT NAME="FIELD_NAME"> </PKIT_ERRORFONT> tag. To use, pass an input profile to the validate method of Apache::PageKit::Model from your perl code option.

Sticky HTML Forms

Uses HTML::FillInForm to implement Sticky CGI Forms.

One useful application is after a user submits an HTML form without filling out a required field. PageKit will display the HTML form with all the form elements containing the submitted info.

Multiple Views/Co-branding

Any page can have multiple views, by using the pkit_view request parameter. One example is Printable pages. Another is having the same web site branded differently for different companies.

Components

PageKit can easily share HTML templates across multiple pages using components. In addition, you may specify Perl code that gets called every time a component is used by adding a component_id method to the Model.

Language Localization

You may specify language properties by the xml:lang attribute for <CONTENT_VAR> and <CONTENT_LOOP> tags in the XML content files.

The language displayed is based on the user's preference, defaulting to the browser settings.

METHODS

The following methods are available to the user as Apache::PageKit API.

prepare_page

This executes all of the back-end business logic need for preparing the page, including executing the page and component code.

prepare_and_print_view

This fills in the view template with all of the data from the back-end, then prints it.

startup

This function should be called at server startup from your httpd.conf file:

<Perl>
      Apache::PageKit->startup("/path/to/pagekit/files","staging");
</Perl>

Where the first argument is the root directory of the PageKit application. The second (optional) argument is the server id. It loads /path/to/pagekit/files/Model into the perl search path so that PageKit can make calls into MyPageKit::Common and other Model classes. It also loads the Config and Content XML files and pre-parses the View template files.

MARKUP TAGS

Most tags get "compiled" into <TMPL_VAR>, <TMPL_LOOP>, <TMPL_IF>, <TMPL_UNLESS>, and <TMPL_ELSE> tags. See the HTML::Template manpage for description of these tags.

<PKIT_COMPONENT NAME="component_id">

Calls the component code (if applicable) and includes the template for the component component_id.

Note that components get dynamically loaded at runtime. For example you can do the following:

<MODEL_LOOP NAME="foo">
  <PKIT_COMPONENT NAME="<MODEL_VAR NAME="bar">">
</MODEL_LOOP>

<PKIT_ERRORFONT NAME="FIELD_NAME"> </PKIT_ERRORFONT>

This tag highlights fields in red that Apache::PageKit::Model reported as being filled in incorrectly.

<PKIT_VAR NAME="HOSTNAME">

Returns the hostname in the URL of the page being served. Particulary useful when you have production and development servers and you need to link to a secure page.

Note that if you are running a proxy server in front of the PageKit server, you probably want to use mod_proxy_add_uri.c. PageKit will extract the hostname from the frontend server using the X-Original-URI header that mod_proxy_add_uri sets.

<PKIT_LOOP NAME="MESSAGE"> </PKIT_LOOP>

Displays messages passed to $model->pkit_message method.

Template should contain something that looks like

<PKIT_LOOP NAME="MESSAGE">
   <PKIT_IF NAME="IS_ERROR"><font color="#ff0000"></PKIT_IF>
   <PKIT_VAR NAME="MESSAGE">
   <PKIT_IF NAME="IS_ERROR"></font></PKIT_IF>
   <p>
</PKIT_LOOP>

This code will display error message seperated by the HTML <p> tag, highlighting error messages in red.

<PKIT_VAR NAME="SELFURL">

The URL of the current page, including CGI parameters. Appends a '&' or '?' at the end to allow additionial parameters.

Note that if you are running a proxy server in front of the PageKit server, you probably want to use mod_proxy_add_uri.c (available from http://tjmather.com/mod_proxy_add_uri.c ). PageKit will take the URL from the frontend server using the X-Original-URI header that mod_proxy_add_uri sets.

<PKIT_IF NAME="VIEW:view"> </PKIT_IF>

Set to true if pkit_view request parameter equals view.

OPTIONS

Global, server and page configuration variables are described in the Apache::PageKit::Config perldoc page. In addition you can set up the session management in MyPageKit::Common.

REQUEST PARAMETERS

These are parameters that are specified in GET requests and POST requests where Content-type is one of application/x-www-form-urlencoded or multipart/form-data.

pkit_credential_#

Login data, typically userid/login/email (pkit_credential_0) and password (pkit_credential_1).

pkit_done

The page to return to after the user has finished logging in or creating a new account.

pkit_lang

Sets the user's preferred language, using a ISO 639 identifier.

pkit_login_page

This parameter is used to specify the page that user attempted to login from. If the login fails, this page is redisplayed.

pkit_login

If this is set to true, then an attempt to log in is made.

pkit_logout

If this is set to true, logs user out.

pkit_remember

If set to true upon login, will save user's cookie so that they are still logged in next time they restart their browser.

pkit_view

Used to implement multiple views/co-branding. For example, if set to print, will search for templates in the View/print directory before using templates in the View/Default directory, and sets the pkit_view:print parameter in the view to true.

FREQUENTLY ASKED QUESTIONS

Please look in here before you send me an email.

1) I get a segmentation fault when I start the PageKit enabled Apache server.

PageKit requires XML::Parser, which is incompatible with the expat library included in Apache. You'll have to configure Apache with --disable-rule=expat.

For more information see http://axkit.org/faq.xml under "I install AxKit and Apache segfaults when it starts".

SEE ALSO

Apache::PageKit::Config, Apache::PageKit::Content, Apache::PageKit::Error, Apache::PageKit::Model, Apache::PageKit::View, Apache::Request, HTML::FillInForm, HTML::Template, HTML::FormValidator

VERSION

This document describes Apache::PageKit module version 0.97

NOTES

Requires mod_perl, XML::Parser, HTML::Clean, HTML::FillInForm, HTML::FormValidator, and HTML::Template.

I wrote these modules because I needed an application framework that was based on mod_perl and seperated HTML from Perl. HTML::Embperl, Apache::ASP and HTML::Mason are frameworks that work with mod_perl, but embed Perl code in HTML. The development was inspired in part by Webmacro, which is an open-source Java servlet framework that seperates Code from HTML.

The goal is of these modules is to develop a framework that provides most of the functionality that is common across dynamic web sites, including session management, authorization, form validation, component design, error handling, and content management.

If you have used (or are considering using) these modules to build a web site, please drop me a line with the URL of your web site. My e-mail is tj@anidea.com. Thanks!

BUGS

This framework is in alpha stage. The interface may change in later releases.

Please submit any bug reports, comments, or suggestions to tjmather@anidea.com, or join the Apache::PageKit mailing list at http://lists.sourceforge.net/mailman/listinfo/pagekit-users

TODO

Associate sessions with authenticated user ID.

Add web based editing tools allowing authorized user to edit View, Content and Configuration files

Add more tests to the test suite.

Make content sharable across pages.

Move Apache::PageKit::Error to seperate distribtuion, use CGI::Carp?

AUTHOR

T.J. Mather (tjmather@anidea.com)

CREDITS

Fixes, Bug Reports, Docs have been generously provided by:

Stu Pae
Yann Kerhervé
Boris Zentner
Chris Burbridge

Thanks!

COPYRIGHT

Copyright (c) 2000, 2001 AnIdea Corporation. All rights Reserved. PageKit is a trademark of AnIdea Corporation.

LICENSE

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Ricoh Source Code Public License for more details.

You can redistribute this module and/or modify it only under the terms of the Ricoh Source Code Public License.

You should have received a copy of the Ricoh Source Code Public License along with this program; if not, obtain one at http://www.pagekit.org/license

cpanm Apache::PageKit

perl -MCPAN -e shell
install Apache::PageKit