The functions.php File

Functions.php is one of the two mandatory files in any WordPress system (the other is style.css). It contains system level functions and others which are used by more than one script (template or other PHP code). It also includes WordPress hooks (actions and filters). It has eight sections:

• Section 1 Utility functions
• Section 2 Dashboard customisation functions
• Section 3 Basic functionality
• Section 4 Widget and sidebar functions
• Section 5 Page formatting functions
• Section 6 List page generation functions
• Section 7 WPForms functions
• Section 8 Member App functions

Section 99 at the end of the file is commented out. It contains redundant code that has been removed from operational use but which has been retained in case it is ever needed again.

Section 1 – Utility functions

Section 2 – Dashboard customisation functions

Section 3 – Basic functionality

* These actions were added at the start of the development of the MGF site and some or all of them are possibly redundant.

Section 4 – Widget and sidebar functions

This section registers the widgets to be used in sidebars and the footer. Example:

function diaries_widgets_init() {
	register_sidebar( array(
		'name'          => 'Garden Diaries',
		'id'            => 'garden-diaries',
		'before_title'	=> '<h5>',
		'after_title'	=> '</h5>',
	    'before_widget' => '<span>',
		'after_widget'  => '</span>',
	) );
}
add_action( 'widgets_init', 'diaries_widgets_init' );

To insert a widget in a sidebar, its id as registered here must be called in the appropriate sidebar-xxx.php file:

<div class="sidebar-right-325 sidebar-style">
<?php if ( !function_exists( 'dynamic_sidebar' ) || !dynamic_sidebar( 'garden-diaries' ) ) : ?>
<?php endif; ?>
</div>

Content for widgets is added via the dashboard: Appearance -> Widgets. This will displa a list of available widgets by the name assigned to them in the registration entry.

Section 5 – Page formatting functions

This section contains functions that are used to format pages.

* The widget editor does not allow the insertion of HTML tags in the title. If the title is to be shown on two lines then insert ‘brnl’ where the line break is to occur. The filter will replace this with a <br> tag.

Section 6 – List page generation functions

This section contains the code for creating the List Generation page and for calling the generation of specific pages. It also contains functions used by the various list generation plugins.

Section 7 – WPForms functions

WPForms is a commercial plugin that allows the easy creation of forms. Each form created is given a unique number by which it is identified. MGF uses the plugin for:

• adding new members (membership form and admin new member form)
• bulk communications with members (broadcast and subscription renewals)
• user login.

It has a number of filters and actions which allow supplementary processing.

Section 8 – Member App functions

This section contains various functions used by the Member App.

The wp-content Folder

Although the wp-content folder does contain some WordPress core code (see items marked * in the table below), its principal function is to house the additional code provided by third parties or developed in-house. It also stores the Media Library.

Third Party Code – Plugins

The WordPress core only provides basic functionality. Additional features can be added by means of plugins. There are thousands of these which will do most of what you might want to do but if all else fails, you can write your own. Many plugins are free but most have a premium version for which you have to pay. Maintenance of plugins is via the ‘Plugins’ item of the dashboard sidebar. Here you can see which plugins you have installed and whether or not they are activated. You can also search for new plugins in the WordPress Plugin Directory (and, for security reasons) nowhere else. The MGF site uses some 40 plugins (not counting in-house developments). Some of the functionality provided by these plugins is relatively simple (e.g. ones which provide additional blocks for the Gutenberg editor); others provide sophisticated and necessary functionalities such as site security and backup.  MGF pays for five plugins; for the rest, the functionality provided by the free version is sufficient. Plugins are located in the wp-content/plugins folder. A full list of the plugins used by MGF can be found here.  

Third Party Code – Additional Libraries

Additional functionality can also be provided by external code libraries. MGF uses two, both installed via the dependency manager, Composer. Brevo API links the Member App to the Brevo messaging system which MGF uses to send emails to members. The phpspreadsheet library allows WordPress code to interface with an Excel spreadsheet. This is used in a number in-house developed plugins that generate list pages. The code for these two libraries is stored in the wp-content/library-brevo and wp-content/phpspreadsheet folders, respectively.

Theme-related code

Plugins and libraries can be used across a site; other code will be limited to a given theme. Such code is stored in the wp-contents/themes/[themename] folder. The MGF site uses an in-house developed theme, mgftheme. Theme-related code can be grouped into five categories:

• templates;
• headers, footers and sidebars;
• style sheets (CSS);
• functions;
• scripts.

When creating a WordPress page, the user assigns to it a template. This frames the content of the page and, together with the CSS files of the theme, determines its appearance. Templates are executable files which WordPress runs when the page is selected for display. WordPress has a default set of templates but users can create their own and the MGF site makes extensive use of these. For more details, see here.

Headers, footers and sidebars define the outline of a page. For more details, see here.

The principal style file for a WordPress theme is the style.css file. For more details on the style files used by the MGF theme, see here.

Although it is inadvisable to change the WordPress core code, the system does provide a means to add functionality at different points in its execution. This functionality is provided by filters and actions which are fired when certain events (such as a page load) occur. Both filters and actions cause code to be executed. Such code is stored in the functions.php file of the theme. This file also contains functions which are used in more than one template or plugin.

Most in-house developed code will be in either a template or in the functions.php file. However, some code modules will be used in more than one template and so these are stored in a separate folder: wp-content/scripts.

Media Library

Images and other files such as PDFs that are uploaded into the Media Library are stored in the wp-contents/uploads folder. This further subdivided by year and month of the upload. Thus, images uploaded in June 2022 will be found in the wp-content/uploads/2022/06 folder. When images are uploaded, WordPress automatically makes three copies of them, correlating to the three image sizes in WordPress: thumbnail, medium, and large.

Some plugins also make use of the wp-content/uploads folder for their own purposes with folders of their own which should not be modified.

Content of wp-content folder as of 8 December 2023

Content of wp-content/images folder as of 8 December 2023

The public_html Folder

The public_html folder contains all the code for the operation of the site; it also contains the Media Library. With one exception, all the site-specific content is in the wp-content folder and anything outside of this folder should not be modified other than by the standard update procedures (see the Site Management and Administration page). The exception is the group of three composer files, together with the accompanying vendor folder. These constitute the Brevo API which is used to send communications to members. There is a new version of this API which, when installed, will be placed in the wp-content folder. At this point the files and folder containing the old API can be deleted.

Contents of the public_html folder as of 8 December 2023

The WordPress Database

With the exception of the media items such as images and PDF files, the WordPress database contains all the information relating to the site:

• the content of the public pages;
• information regarding the structure of the site;
• member information and their roles;
• information used by plugins;
• information used by MGF functions.

List of database tables as of 27 November 2023

NOTE: In a standard WP database the table names begin with ‘wp_’ – e.g. ‘wp_users’. For the MGF site, the prefix is ‘wp_mgf_’, so wp_mgf_users’. The prefix is defined in public_html/wp-config.php.

(Items marked with an asterisk indicate that there are several tables beginning with the text shown)

For a description of the purpose of the WordPress standard tables, see the WordPress Database Description.

To view the database, click ‘WP-phpMyAdmin’ in the dashboard sidebar and then click ‘Enter local phpMyAdmin’.