Ramu Ramakesavan Phoenix Drupal User Group

January 2012

hook

HOOK

HTML

CSS Style Sheets

JavaScripts

PHP, Perl

Themes, Regions, Blocks Forms, Views, Panels Administration Module, Hooks Caching Debug

MySQL

Drupal Framework

Apache Webserver

AJAX

Client Side Server Side

Drupal Installation

Updates/ Upgrades Crawlers

• Display of data on the webpage

• Structured presentation

• Site specific modifications to presentation

• Creation of data for the webpage

• Drupal7 mechanism for data creation

• flow of control during data creation (PHP code)

• Site specific modifications to data creation

• Searchable and editable data format

themes/bartik/bartik.info

Option „Demo block regions‟ under structure/block in adminstration

•modules/system/page.tpl.php •themes/bartik/templates/page.tpl.php

•modules/system/html.tpl.php

• template_preprocess; template_preprocess_<theme_element> • (web/includes/theme.inc) • default variables for all theme element/ specific theme elements • theme_element: page, html, block, region, maintenance_page

• <mymod>_preprocess; <mymod>_preprocess_<theme_element> • (web/sites/all/modules/<mymod>) • modules that didn't define the theme hook can alter the variables.

• <ENGINE>_engine_preprocess;<ENGINE>_engine_preprocess_<theme_element> • (web/themes/engines/phptemplate/phptemple.engine) • Drupal uses PHPTemplate as default engine

• <THEME>_preprocess; <THEME>_preprocess_ <theme_element> • (web/sites/all/theme/template.php) • Theme Bartik can set variables

• template_process; template_process_<theme_element> • (web/includes/theme.inc) • default variables for all theme element/ specific theme elements • theme_element: page, html, block, region, maintenance_page

• <mymod>_process; <mymod>_process_<theme_element> • (web/sites/all/modules/<mymod>) • modules that didn't define the theme hook can alter the variables.

• <ENGINE>_engine_process;<ENGINE>_engine_process_<theme_element> • (web/themes/engines/phptemplate/phptemple.engine) • Drupal uses PHPTemplate as default engine

• <THEME>_process; <THEME>_process_ <theme_element> • (web/sites/all/theme/template.php) • Theme Bartik can set variables

If implemented using a real function instead of page.tpl.php then only XXXX_preprocess_<theme_element> XXXX_process_<theme_element> routines are executed Pre_process/process functions can define theme_hook_suggestion and

theme_hook_suggestions that can override current theme implementation

links_contextual_node defines fallback implementations for named

objects / contexts Function a_b_c Function a_b Function a

Question: When should these capabilities be used?

• Display of data on the webpage

• Structured presentation

• Site specific modifications to presentation

• Creation of data for the webpage

• Drupal7 mechanism for data creation

• flow of control during data creation (PHP code)

• Site specific modifications to data creation

• Searchable and editable data format

A web-page is created when a http://www.ramustores.com/?q=examples/theming_example

is entered at the URL box in a browser

A web-page is updated when a Menu item that is assigned http://www.ramustores.com/?q=examples/theming_example

is selected

Modules register path-CBfunction mapping that are stored in menu_router table

Simplified URL works on top of this?

function <mymodule>_menu() {

$items['examples/theming_example'] =

array(

'title' => 'Theming Example',

'description' => 'Some theming examples.',

'page callback' => 'theming_example_page',

'access callback' => TRUE,

'access arguments' => array('access content'),

);

$items['examples/theming_example/theming_example_list_page'] =

array(

'title' => 'Theming a list',

'page callback' => 'theming_example_list_page',

'access arguments' => array('access content'),

'weight' => 1,

);

return $items;

}

function theming_example_page() {

$content[0] = t('Some examples of pages and forms that are run through theme functions.');

$content[1] = l(t('Simple page with a list'), 'examples/theming_example/theming_example_list_page');

$content[2] = l(t('Simple form 1'), 'examples/theming_example/theming_example_order_form');

$content[3] = l(t('Simple form 2'), 'examples/theming_example/theming_example_text_form');

$content['#theme_wrappers'] = array('theming_example_content_array');

return $content;

}

1, User enters URL _http://localhost/web/?q=examples/theming_example

2. Drupal executes code in web/index.php

invokes function menu_execute_active_handler

3. menu_execute_active_handler (menu.inc) does the following

searches menu_router for (examples/theming_example) and gets corresponding CallBackFunction.

MainContent=CBfunction(“examples/theming_example”)

drupal_deliver_page(MainContent, HTML (not AJAX or XML)) defined in menu.inc

4. Drupal_deliver_page (common.inc) does the following:

drupal_deliver_html_page (MainContent)

5. Drupal_deliver_html_page (common.inc) does the following:

drupal_render_page(MainContent)

1. drupal_render_page($MainContent) (common.inc) does the following:

1. Copies the $MainContent into $page[„current‟]

2. Invokes <module>_page_build ($page)

each modules adds its data

3. Invokes drupal_alter( $page)

Your custom module can alter the contents of $page

4. Invokes drupal_render($page)

================================================

block_page_build(„html page‟) (defined in block.module) does the following

1. $all_regions = system_region_list($theme);

2. for each ($region in $all_regions) {

if ($blocks = block_get_block_by_regions($region)) {

$page[$region] = $blocks;

endif

endfor

drupal_alter (module.inc) does the following:

1. Invokes each module that has defined <module>_page_alter.

1. Drupal_render($page) (common.inc) hands over to the presentation layer (ie. Theming)

1. Recursively invokes „theme()‟ to generate HTML code

First it calls page.tpl.php for Bartik

Next it calls html.tpl.php from system module

$page = array(

'#show_messages' => TRUE,

„#theme_wrappers‟=> „html‟

'#theme' => 'page',

'#type' => 'page',

'content' => array( 'system_main' => array(...), 'another_block' => array(...), '#sorted' => TRUE,

),

'sidebar_first' => array( ... ),

'sidebar_second' => array( ... ),

'footer' => array( ... )

Searchable & editable array with key-value pairs. Keys are searchable

the data used to build a page is kept as render_array until they are ready to be displayed using user selected theme

Allows flexibility in changing the layout or content of a page

Alter and preprocess functions work with Render Array

Rendering = transforming render array into HTML

render([page[„content‟]) = drupal_render(page[„content‟]);

_http://chicago2011.drupal.org/sessions/render-api-drupal-7

(franz heinzmann)

_http://www.archive.org/details/PageRenderDrillDownInDrupal7

(moshe wiseman)

_http://pingv.com/blog/a-peek-at-drupal-7-theme-system-changes

_http://pingv.com/blog/grok-drupal-7-theming-update

(Laura Scott)

_http://drupal.org/node/930760 (render arrays in Drupal 7)

Questions?