NAME

Rose::DBx::Object::Renderer - Web UI Rendering for Rose::DB::Object

SYNOPSIS

  use CGI;
  my $query = new CGI;
  print $query->header();

  use Rose::DBx::Object::Renderer;

  # Load a database called 'company', which has two tables 'employee' and 'position' where employee has a position
  load_database('company', {db_username => 'root', db_password => 'root'});

  # Render a form to add employees
  Company::Employee->render_as_form();

  # Load an object
  my $e = Company::Employee->new(id => 1);
  $e->load;

  # Render a link to google map for the 'address' column
  print $e->address_for_view();

  # Render a form with using the default template with custom fields
  $e->render_as_form(
    template => 1,
    fields => {'hobby' => {required => 1, options => ['Coding', 'Reading', 'Cooking']}},
  );

  # Render a table
  Company::Employee::Manager->render_as_table();

  # Render a table for all the employees who love to code with create, edit, and delete access
  Company::Employee::Manager->render_as_table(
    get => {query => [hobby => 'Coding']}
    order => ['first_name', 'email', 'address', 'phone'],
    create => 1, 
    edit => 1,
    delete => 1,
  );

  # Render a table with search and a custom template
  Company::Employee::Manager->render_as_table(
    get => {require_objects => [ 'position' ]},
    searchable => ['first_name', 'last_name', 'position.title'],
    template => 'custom_template.tt'
  );


  # Render a menu
  my $menu = Company::Employee::Manager->render_as_menu (
    order => ['Company::Employee', 'Company::Position'],
    output => 1
  );

  print $menu->{output};


  # Render a pie chart
  Company::Employee::Manager->render_as_chart(
    type => 'pie',
    values => ['Coding', 'Cooking'],
    column => 'hobby',
  );

  # Render a bar chart using Google Chart API
  Company::Employee::Manager->render_as_chart(
    type => 'bar',
    title => 'The Employee Bar Chart',
    description => 'A useful bar chart.',
    columns => ['salary', 'tax'],
    objects => [1, 2, 3],
	options => {chco => 'ff6600,ffcc00'} # the color for each bar
  );

DESCRIPTION

Rose::DBx::Object::Renderer generates web UIs for Rose::DB::Object. It encapsulates many web conventions in the generated UIs as default behaviours. For example, email addresses are by default rendered as mailto links in tables and appropiate validation is enforced automatically in forms. These behaviours are highly configurable and extensible.

Renderer uses CGI::FormBuilder to generate forms and the Google Chart API to render charts. Template::Toolkit is used for template processing, however, Renderer can dynamically generate the full set of UIs without any templates.

RESTRICTIONS

The database table must follow the conventions in Rose::DB::Object.
Support for database tables with multiple primary keys is limited.

CONFIGURATION

$Rose::DBx::Object::Renderer::CONFIG is the global config hash.

Database Connection

The load_database method by default uses the settings in $Rose::DBx::Object::Renderer::CONFIG to connect a database.

# Use the DBD for PostgreSQL (defaulted to 'mysql')
$Rose::DBx::Object::Renderer::CONFIG->{db}->{type} = 'Pg'; 

$Rose::DBx::Object::Renderer::CONFIG->{db}->{port} = '5543';
$Rose::DBx::Object::Renderer::CONFIG->{db}->{username} = 'admin';
$Rose::DBx::Object::Renderer::CONFIG->{db}->{password} = 'password';

# Change the Rose::DB::Object convention such that database table names are singular 
$Rose::DBx::Object::Renderer::CONFIG->{db}->{tables_are_singular} = 1;

Paths

The default TT INCLUDE_PATH is './template', which can be changed in:

$Rose::DBx::Object::Renderer::CONFIG->{template}->{path} = '../templates:../alternative';

Renderer also needs a directory with write access to upload files. The default upload path is './upload'.

# Change the upload directory
$Rose::DBx::Object::Renderer::CONFIG->{upload}->{path} = '../uploads';

# Change the url for the upload directory
$Rose::DBx::Object::Renderer::CONFIG->{upload}->{url} = '../uploads';

Default Settings for Rendering Methods

We can modify the default settings of the rendering methods, for example:

# Change the default form template
$Rose::DBx::Object::Renderer::CONFIG->{form}->{template} = 'custom_form.tt';

# Change the default number of rows per page to 25 in tables
$Rose::DBx::Object::Renderer::CONFIG->{table}->{per_page} = '25';

# Use 'ilike' to perform case-insensitive searches in PostgreSQL
$Rose::DBx::Object::Renderer::CONFIG->{table}->{search_operator} = 'ilike'; # defaulted to 'like'

# Keep old upload files
$Rose::DBx::Object::Renderer::CONFIG->{form}->{keep_old_file} = 1;

Column Definitions

Renderer embraces a built-in list of commonly-used column types in web applications, such as email, address, photo, document, and media. This list is defined in:

$Rose::DBx::Object::Renderer::CONFIG-E<gt>{columns}

For those who are familiar with CGI::FormBuilder, it is obvious that most of the options inside $Rose::DBx::Object::Renderer::CONFIG->{columns}->{column_name} are in fact CGI::FormBuilder field definitions, except for format, unsortable, and stringify. New column types can be defined by adding to that hash.

format

Renderer encapsulates web-oriented behaviours by injecting the coderefs defined inside the format hashref as object methods, for example:

# Prints the localised DateTime object in 'DD/MM/YYYY' format
print $object->date_for_view;

# Prints the image column in formatted HTML
print $object->image_for_view;

# Prints the url of the image
print $object->image_url;

# Prints the file path of the image
print $object->image_path;

In order to generate web-ready UIs, these extended object methods take preference over the the default object methods. The for_edit and for_update methods are used by render_as_form. The for_edit methods are triggered to format column values during form rendering, while the for_update methods are triggered to update column values during form submission. Similarly, the for_view, for_search, and for_filter methods are used by render_as_table. The for_view methods are used to format column values during table rendering, while the for_filter and for_search methods are respectively triggered for column filtering and keyword searches.

We can customise existing formatting methods or define new ones easily. Let's say we would like to use the HTML::Strip module to strip out HTML for the 'description' column:

use HTML::Strip;
...
$Rose::DBx::Object::Renderer::CONFIG->{columns}->{description}->{format}->{for_update} = sub{
  my ($self, $column, $value) = @_;
  return unless $value;
  my $hs = HTML::Strip->new(emit_spaces => 0);
  my $clean_text = $hs->parse($value);
  return $self->$column($clean_text);  
};

We can always use the modified method directly:

load_namespace('company');
my $p = Company::Product->new(id => 1);
$p->load;

$p->description_for_update('<html>The Lightweight UI Generator.</html>');
print $p->description;
# which prints 'The Lightweight UI Generator.'

$p->save();

We can create a custom method for the 'first_name' column so that users can click on a link to search the first name in CPAN:

$Rose::DBx::Object::Renderer::CONFIG->{columns}->{first_name}->{format}->{in_cpan} = sub{
my ($self, $column) = @_; 
my $value = $self->$column; 
return qq(<a href="http://search.cpan.org/search?query=$value&mode=all">$value</a>) if $value;
};
...
load_namespace('company');
my $e = Company::Employee->new(id => 1);
$e->load;
print $e->first_name_in_cpan;

# or use it directly inside a template: [% e.first_name_in_cpan %]

unsortable

This parameter defines whether a column is a sortable column in tables. For example, the 'password' column is by default unsortable, i.e.:

$Rose::DBx::Object::Renderer::CONFIG->{columns}->{password}->{unsortable} = 1;

Custom columns are always unsortable.

stringify

This parameter specifies which columns are stringified. This is used by the exported stringify_me object method.

$Rose::DBx::Object::Renderer::CONFIG->{columns}->{first_name}->{stringify} = 1;

METHODS

`load_database`

load_database loads database tables into classes using Rose::DB::Object::Loader. In order to eliminate the need for manually mapping column definitions to database table columns, load_database also tries to automatically assign a built-in column definition to each column of the loaded classes by matching the column definition name with the database table column name.

load_database accepts three parameters. The first parameter is the database name, the second parameter is a hashref that gets passed directly to the Rose::DB::Object::Loader constructor, while the last parameter is passed to the make_classes method. load_database always use the title case of the database name as the class_prefix unless it is specified. load_database returns an array of the loaded classes via the make_classes method in Rose::DB::Object::Loader. However, if the Rose::DB::Object base_class for the database already exists, which most than likely happens in a persistent environment, load_database will simply skip the loading process and return nothing.

load_database(
  'company',
  {db_username => 'admin', db_password => 'password'},
  {include_tables => ['employee','position']}
);

Common Parameters in Rendering Methods

template

A string to define the name of the TT template for rendering the UI. When it is set to 1, it will use the default templates defined in $CONFIG. For instance, the default template for render_as_form is defined in $CONFIG->{form}->{template}.

prefix

A string to set a prefix for a UI. prefix is used to prevent CGI param conflicts between multiple generated UIs on the same page.

title

A string to set the title of the UI.

description

A string to set the description of the UI.

no_head

When set to 1, rendering methods will not include the default DOCTYPE and CSS styles defined in $CONFIG->{misc}->{html_head}. This is useful when rendering multiple UIs in the same page.

output

When set to 1, the rendering methods would return the rendered UI instead of printing it directly. For example:

my $form = Company::Employee->render_as_form(output => 1);
print $form->{output};

extra

A hashref of additional variables passed to the template.

Company::Employee->render_as_form(extra => {hobby => 'basketball'});

template_options

Optional parameters to be passed to template toolkit. This is not applicable to render_as_form.

`render_as_form`

render_as_form renders forms and handles the submission.

# Render a form for creating a new object instance
Company::Employee->render_as_form();

# Render a form for updating an existing object instance
my $e = Company::Employee->new(id => 1);
$e->load;
$e->render_as_form();

order

render_as_form by default sorts all fields based on the column order of the underlying database table. order accepts an arrayref to define the order of the form fields to be shown.

fields

Accepts a hashref to overwrite the CGI::FormBuilder field definitions auto-initialised by render_as_form. Any custom fields must be included to the order arrayref in order to be shown.

Company::Employee->render_as_form(
  order => ['username', 'password', 'confirm_password', 'favourite_cuisine'],
  fields => {
  password => {required => 1, class=> 'password_css'},
});

Please note that 'confirm_password' is also a built-in column inside Renderer. The default validation Javascript will work automatically, unless the password field is not called 'password' or when a prefix is used, in which case, the validation code should be updated accordingly.

queries

An arrayref of query parameters to be converted as hidden fields.

Company::Employee->render_as_form(
  queries => {
  'rm' => 'edit',
  'favourite_cuisine' => ['French', 'Japanese']
});

Please note that when a prefix is used, all fields are renamed to 'prefix_fieldname'.

controllers and controller_order

Controllers are essentially callbacks. We can add multiple custom controllers to a form. They are rendered as submit buttons. controller_order defines the order of the controllers, in other words, the order of the submit buttons.

my $form = Employee::Company->render_as_form(
  output => 1,
  controller_order => ['Hello', 'Good Bye'],
  controllers => {
    'Hello' => {
      create => sub {
        return if DateTime->now->day_name eq 'Sunday';
        return 1;
      },
      callback => sub {
        my $self = shift;
        if (ref $self)
        {
          return 'Hello ' . $self->first_name;
        }
        else
        {
          return 'No employee has been created'.
        }
    },
    'Good Bye' => \&say_goodbye
  });

if (exists $form->{controller})
{
  print $form->{controller};
}
else
{
  print $form->{output};
}

sub say_goodbye
{
  return 'Good Bye';
}

Within the controllers hashref, we can set the create parameter to 1 so that the object is always inserted into the database before running the custom callback. We can also point create to a coderef, in which case, the object is inserted into the database only if the coderef returns true.

Similarly, when rendering an object instance as a form, we can update the object before running the custom callback:

...
$e->render_as_form(
  controllers => {
    'Hello' => {
      update => 1,
      callback => sub{...};
    }
);

Another parameter within the controllers hashref is hide_form, which informs render_as_form not to render the form after executing the controller.

cancel

render_as_form has a built-in controller called 'Cancel'. cancel is a string for renaming the default 'Cancel' controller in case it clashes with custom controllers.

form

Parameters for the CGI::FormBuilder constructor.

validate

Parameters for the CGI::FormBuilder's validate method.

jserror

When a template is used, render_as_form sets CGI::FormBuilder's jserror function name to 'notify_error' so that we can always customise the error alert mechanism within the template (see the included 'form.tt' template).

show_id

Shows the ID column (primary key) of the table as a form field when it is set to 1. This is generally not a very good idea except for debugging purposes.

javascript_code

A string with javascript code to be added to the template

render_as_form calls CGI::FormBuilder's $form->template() method to process template. Thus, we can access the form object via the [% form %] variable. Additionally, The order of the form fields are defined by [% field_order %]. We can also access the calling object (or class) using the [% self %] variable.

`render_as_table`

render_as_table renders tables for CRUD operations.

or_filter

render_as_table allows columns to be filtered via URL. For example:

http://www.yoursite.com/yourscript.pl?first_name=Danny&last_name=Liang

returns the object where 'first_name' is 'Danny' and 'Last_name' is 'liang'. By default, column queries are joined by "AND", unless or_filter is set to 1.

columns

The columns parameter can be used to define custom columns which do not physically exist in the database table

Company::Employee::Manager->render_as_table(
  columns => {'custom_column' => 
    label => 'Total',
    value => {
      1 => '100', # the 'Total' is 100 for object ID 1
      2 => '50'
    },
});

order

order accepts an arrayref to define the order of the columns to be shown. The order parameter also determines which columns are allowed to be filtered via url.

searchable

searchable enables search for multiple columns.

Company::Employee::Manager->render_as_table(
  searchable => ['first_name', 'hobby'], #search for those fields
);

# A search box will be shown in rendered table. In the web browser, we can now do http://www.yoursite.com/yourscript.pl?q=coding

get

get accepts a hashref to construct database queries. get is directly passed to the get method of the manager class.

  Company::Employee::Manager->render_as_table(
    get => {
	  per_page = 5,
      require_objects => [ 'position' ],
      query => ['position.title' => 'Manager'],
    });

controllers and controller_order

The controllers parameter works very similar to render_as_form. controller_order defines the order of the controllers.

  Company::Employee::Manager->render_as_table(
	controller_order => ['edit', 'Review', 'approve'],
    controllers => {
      'Review' => sub{my $self = shift; do_something_with($self);}
      'approve' => {
	    label => 'Approve',
        hide_table => 1,
        queries => {approve => '1'}, 
        callback => sub {my $self = shift; do_something_else_with($self);
      }
    }
  );

Within the controllers hashref, the queries parameter allows us to define custom query strings for the controller. The hide_table parameter informs render_as_table not to render the table after executing the controller.

create

This enables the built-in 'create' controller when set to 1.

Company::Employee::Manager->render_as_table(create => 1);

Since render_as_form is used to render the form, we can also pass a hashref to manipulate the generated form.

Company::Employee::Manager->render_as_table(
  create => {title => 'Add New Employee', fields => {...}}
);

edit

Similar to create, edit enables the built-in 'edit' controller for updating objects.

delete

When set to 1, delete enables the built-in 'delete' controller for removing objects.

queries

Similar to the queries parameter in render_as_form, queries is an arrayref of query parameters, which will be converted to query strings. Please note that when a prefix is used, all query strings are renamed to 'prefix_querystring'.

url

Unless a url is specified in url, render_as_table will resolve the self url using CGI.

show_id

Shows the id column (primary key) of the table when it is set to 1. This can be also achieved using the order parameter.

javascript_code

A string with javascript code to be added to the template

ajax and ajax_template

These two parameters are designed for rendering Ajax-enabled tables. When ajax is set to 1, render_as_table will use the template defined either via the ajax_template parameter or in $CONFIG->{table}->{ajax_template}. render_as_table also passes a variable called 'ajax' to the template and sets it to 1 when a CGI param called 'ajax' is set. We can use this variable in the template to differentiate whether the current request is an ajax request or not.

Within a template, we can loop through objects using the [% table %] variable. Alternatively, we can use the [% objects %] variable.

`render_as_menu`

render_as_menu generates a menu with the given list of classes and renders a table for the current class. We can have fine-grained control over each table within the menu. For example, we can make the 'date_of_birth' field to be mandatory inside the 'create' form of the 'Company::Employee' table within the menu:

  my $menu = Company::Employee::Manager->render_as_menu (
    order => ['Company::Employee', 'Company::Position'],
    items => {
    'Company::Employee' => {
      create => {
	    fields => {date_of_birth => {required => 1}}
	  }
    }
    'Company::Position' => {
	  title => 'Current Positions',
      description => 'important positions in the company'
    }},
    create => 1,
    edit => 1,
    delete => 1,
  );

order: The order parameter defines the list of classes to be shown in the menu as well as their order. The current item of the menu is always the calling class, i.e. Company::Employee::Manager in the example.
items: The items parameter is a hashref of parameters to control each table within the menu.
create, edit, delete, and ajax: These parameters are shortcuts which get passed to all the underlying tables rendered by the menu.

The [% items %] variable passed to a template defines the menu item, which order is determined by the [% item_order %] variable.

`render_as_chart`

render_as_chart renders pie, line, and bar charts via the Google Chart API.

type: This can be either 'pie', 'bar', or 'line'.
column and values: These two parameters are only applicable to pie charts. column defines the column of the table in which the values are compared. The values parameter is a list of values to be compared in that column, i.e. the slices.
columns and objects: These two parameters are only applicable to bar and line charts. columns defines the columns of the object to be compared. The objects parameter is a list of object IDs representing the objects to be compared.
options: A hashref for specifying any Google Chart API options which is serialised into a querystring.
engine: Accepts a coderef for your own charting engine.

The [% chart %] variable is passed to a template.

OBJECT METHODS

Apart from the formatting methods injected by load_namespace, there are several other less-used object methods.

`delete_with_file`

This is a wrapper of the object's delete method to remove any uploaded files associated:

$object->delete_with_file();

`stringify_me`

The default stringify_me method return a string by joining all the matching columns with the stringify parameter set to true. The default stringify delimiter is comma.

# Change the stringify delimiter to a space
$Rose::DBx::Object::Renderer::CONFIG->{misc}->{stringify_delimiter} = ' '; 
...
$object->title('Mr');
$object->first_name('Rose');
...
print $object->stringify_me();
# prints 'Mr Rose';

This method is used internally to stringify foreign objects as form field values.

`stringify_package_name`

This method stringifies the package name:

print Company::Employee->stringify_package_name(); # Prints 'company_employee'

OTHER CONFIGURATIONS

Javascript

We can also specify the path to contents such as javascript libraries or images used within templates:

$Rose::DBx::Object::Renderer::CONFIG->{template}->{url} = '../docs/';

The default CSS class for the 'address' column is 'disable_editor'. This is for excluding the TinyMCE editor with this setup: editor_deselector : "disable_editor".

Miscellaneous

Other miscellaneous configurations are defined in:

$Rose::DBx::Object::Renderer::CONFIG->{misc}

By default, the 'date', 'phone', and 'mobile' columns are localised for Australia.

Sample Templates

There are four sample templates: form.tt, table.tt, menu.tt, and chart.tt in the 'templates' folder inside the TAR archive.

AUTHOR

Xufeng (Danny) Liang (danny.glue@gmail.com)

COPYRIGHT & LICENSE

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

To install Rose::DBx::Object::Renderer, copy and paste the appropriate command in to your terminal.

cpanm

cpanm Rose::DBx::Object::Renderer

CPAN shell

perl -MCPAN -e shell
install Rose::DBx::Object::Renderer

For more information on module installation, please visit the detailed CPAN module installation guide.

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