NAME

Apache::JAF -- mod_perl and Template-Toolkit web applications framework

SYNOPSIS

controller -- a mod_perl module that drives your application
 package Apache::JAF::MyJAF;
 use strict;
 use JAF::MyJAF; # optional
 # loading mini-handlers & templates during compilation time
 use Apache::JAF (
   handlers => '/examples/site/modules/Apache/JAF/MyJAF/pages/', # 'auto' if you want to use suggested file structure
   templates => '/examples/site/templates/'                      # the same comment
 );
 our @ISA = qw(Apache::JAF);

 # determine handler to call 
 sub setup_handler {
   my ($self) = @_;
   # the page handler for each URI of sample site is 'do_index'
   # you should swap left and right ||-parts for real application
   my $handler = 'index' || shift @{$self->{uri}};
   return $handler;
 }

 sub site_handler {
   my ($self) = @_;
   # common stuff before handler is called
   $self->{m} = JAF::MyJAF->new(); # create modeller -- if needed
   $self->SUPER::site_handler();
   # common stuff after handler is called
   return $self->{status}
 }
 1;
page handler -- controller's method that makes one (or more) pages
 sub do_index {
   my ($self) = @_;
   # page handler must fill $self->{res} hash that process with template
   $self->{res}{test} = __PACKAGE__ . 'test';
   # and return Apache constant according it's logic
   return OK;
 }
modeller -- a module that encapsulates application business-logic
 package JAF::MyJAF;
 use strict;
 use DBI;
 use base qw( JAF );

 sub new {
   my ($class, $self) = @_;
   $self->{dbh} = DBI->connect(...);
   return bless $self, $class;
 }
 1;
Apache configuration (httpd.conf)
  DocumentRoot /examples/site/data
  <Location />
    <Perl>
      use lib qw(/examples/site/modules);
      use Apache::JAF::MyJAF;
    </Perl>
    SetHandler perl-script
    PerlHandler Apache::JAF::MyJAF
    PerlSetVar Apache_JAF_Templates /examples/site/templates
    # optional or can be specified in Apache::JAF descendant (default value is used in example)
    PerlSetVar Apache_JAF_Modules /examples/site/modules/Apache/JAF/MyJAF/pages
    # optional or can be specified in Apache::JAF descendant (default value is used in example)
    PerlSetVar Apache_JAF_Compiled /tmp
  </Location>

DESCRIPTION

Introduction

Apache::JAF is designed for creation web applications based on MVC (Model-View-Controller) concept.

  • Modeller is JAF descendant

  • Controller is Apache::JAF descendant

  • and the Viewer is set of the templates using Template-Toolkit markup syntax

This separation hardly simplifies the dynamic development of sites by designers and programmers. Each programmer works on own part of the project writing separate controller's parts. Designers have to work only on visual performance of templates.

Suggested file structure

Suggested site's on-disk structure is:

  site
   |
   +-- data
   |
   +-- modules
   |
   +-- templates
data

document_root of site. All static files (e.g. JavaScripts, pictures, CSSs etc) must be placed here

modules

Storage place for site modules -- must be in @INC's

templates

The place of your site's templates. Framework is designed to reproduce site's structure in this folder. It's just like document_root for static site.

Request processing pipeline

The Apache::JAF::handler intercepts every request for specified location, and process it's own way:

  1. If requested file exists then nothing happens. The handle declines request with DECLINE.

  2. Otherwise the instance of Apache::JAF's descendant is created and setup_handler method is called. You must override this method and return determined handler's name. Usually it's the first part of URI or just index. Also handlers from Apache_JAF_Modules folder is loaded into package's namespace if $self->{debug_level} > 0 or handlers were not loaded during module compilation.

  3. Then goes site_handler calling. If you have common tasks for each handler you can override it. site_handler calls your own handler. It's name is returned by setup_handler. Usually this "mini-handler" is very simple. It have to be implemented as package method with do_<handler name> name. You have to fill $self->{res} hash with result and return Apache constant according to handler's logic (OK, NOT_FOUND, FORBIDDEN and so on). The sample is shown in "SYNOPSIS".

  4. If the previous step fulfills correctly, and $self->{type} property is text/* then result of processing template returns to client. If type of result is not like text, one more method is needed to implement: on_send_<handeler name>_data. It must return binary data to client. This way you may create handlers for dynamic generation of images, M$ Excel workbooks and any other type of data.

Apache::JAF methods

setup_handler

This method you must override in your Apache::JAF descendant. You must return handler's name (that will be called as do_<handler name> method later) from it depending on URI requested by user. You may set site-wide properties such as debug_level, header or footer, templates and includes extensions and so on. If handler name depends on application logic implemented in modeller then you have to create modeller in this method and store it in m property for later use. The primary setup_handler is shown in "SYNOPSIS".

site_handler

You can override this method to provide common tasks for each of your page-handlers. For example you may create instance of modeller class, provide some custom authorization/authentication or sessions handling and so on. You must call $self>SUPER::site_handler and return $self->{status} from it.

Apache::JAF properties

r

Current Apache::Request object.

filter

Using Apache::Filter flag.

uri

Reference to the array of current URI (splitted by slash). Usually you need to modify it in "setup_handler" method to determine page's handler name. Remained array will be passed to the page-handler method as a list of parameters.

res

Hash reference that holds page-handler results.

expand_path

Boolean flag for complex-name-handlers changes '_' to '/' in handler's name. It provides real-like document tree in the templates folder.

debug_level

Look at Apache_JAF_Debug in "CONFIGURATION" section.

status

Default handler status is NOT_FOUND.

type

Default content-type is text/html. You can call $self->download_type() for set unexisting MIME-type to force browser download content instead of viewing it.

template_ext, include_ext

Default template extension is .html. Default include template extension is .inc.

default_include

Site-wide include template. Default value is... default.

Site-wide pre- and post-include templates. Defalut values are header and footer. Note:You must undef this properies if you want create page-template without it. For example for page in pop-up window (disable_header, disable_footer, and disable_header_footer methods).

templates

Path to the templates folder. You may have different sets of templates for different views of results generated by your page-handlers.

handler

Result of setup_handler method is stored here for later use.

other properites

For internal use only.

Implementing handlers

Page handlers are simple. Their methods are with do_<handler name> name. You have to analyse given parameters, fill out $self->{res} hash with handler results that will be processed with template and return one of Apache::Constants. Usually it's OK, but may be NOT_FOUND if parameters passed to handlers are invalid for some reason.

Look into examples/* folder in the distribution package for some guidelines.

Templates structure and syntax

Template for a specific handler consists of:

1 default.inc

Common [% BLOCK %]s for all site templates. Processed before header and main tamplate.

2 header.inc

Header template. Processed before main handler's template.

3 <handler name>.html

Main handler's template.

4 footer.inc

Footer template. Processed after main handler's template.

Default names and extensions are shown. All of them are configurable in processing handler methods. For example you have to disable processing header and footer for handler that produces not text/* content.

Templates syntax is described at http://www.template-toolkit.org/docs/plain/Manual/.

CONFIGURATION

Apache_JAF_Prefix

Number of URI parts (between slashes) or path that must be removed from request URI. Useful for implementing dynamic part of almost static site. It simplifies names of page handlers.

Apache_JAF_Templates

Path to templates folder. Several paths may be separated by semicolon. Win32 note: This separator works too. Don't get confused with full paths with drive letters.

Apache_JAF_Modules

Path to page handlers folder. By default it's controller location plus /pages.

Apache_JAF_Compiled

Path to compiled templates folder. Default is /tmp. Saving compiled templates on disk dramatically improves overall site performance.

Apache_JAF_Debug

Application's debug level. The amount of debug info written to the Apache error_log. Ranges from 0 to 10.

 0: critical errors only
 1: request processing line
 2: client request
 3: response headers
 4: template variables
 5-8: not used (for future enchancements)
 9: loading additional handlers
 10: processed template

Also this setting affecting page-handlers loading. If debug level is 0 -- handlers are loaded only on server-start. Else handlers loaded on every request. That simplifies development process but increases request processing time. So it's not good to set debug level greater than 0 in production environment.

Note: This setting is overrided by setting $self->{debug_level}.

SEE ALSO

AUTHOR

Greg "Grishace" Belenky <greg@webzavod.ru>

COPYRIGHT

 Copyright (C) 2001-2003 Greg Belenky
 Copyright (C) 2002-2003 WebZavod (http://www.webzavod.ru) programming team

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.