WordPress Architecture ► Core files – PHP ► MySQL database  Configured by the installation script ► wp-content directory  themes subdirectory: layout  plugins subdirectory: extensions  uploads subdirectory: uploaded files ► Version updates relatively painless

Presentation: Choose a Theme Current Theme Default Themes 100’s available Administrator’s View

Theme Architecture ► Set of files installed in a subdirectory of wp-content/themes ► Typical theme set includes  style.css and required images  PHP template files defining parts of the pages ► header, footer, sidebar, comments  PHP template files defining entire pages ► Runtime selection based on template hierarchy template hierarchytemplate hierarchy ► Can also set page template when creating the page Administrator’s View

Template Architecture ► Not Smarty  But does serve to separate content generation from presentation ► Dozens of predefined tags  Simple example: get_header() ► Called “tags,” but most are functions  Example: list categories ► list_cats() – 18 positional parameters ► wp_list_cats() – arguments as name/value pairs Administrator’s View

Editing Templates Administrator’s View

Example template: page.php "> "> ', ' '); ?> ', ' '); ?> Administrator’s View

► get_header ► get_sidebar ► the_title ► the_content ► edit_post_link ► get_footer

Digression: The Loop Administrator’s View …. ► Applies to “WordPress Pages” as well as “pages” that display “WordPress Posts” ► Many tags to control what happens inside  is_category()  is_page()  More conditional tags conditional tagsconditional tags

Extensibility: Plugins Administrator’s View

Sample Plugin: Hello, Dolly Administrator’s View $lyrics = explode("\n", $lyrics); $chosen = wptexturize( $lyrics[ mt_rand(0, count($lyrics) ) ] ); function hello_dolly() { global $chosen; echo " $chosen "; } add_action('admin_footer', 'hello_dolly'); function dolly_css() { echo " echo " #dolly { … style attributes … } </style>";} add_action('admin_head', 'dolly_css');

“Hello, Dolly” in action ► Before activation ► After activation Administrator’s View

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