PHP for WordPress

Slides for a talk at WordCamp Baltimore 2015 about what to know about PHP when starting off with WordPress Development as well as where you can learn all of this.

1. PHP for WordPress Zac Gordon @zgordon
2. What is PHP?
3. Many Developers Learn PHP via WP
4. Often Starts with Theme Customization
5. Some Examples of PHP Theme Customization
6. What to Know Before Learning PHP
7. What to Know 
 About PHP for WordPress
8. • Language Basics • WP Coding Standards • Common Files • The Loop • Template Tags • Conditionals • Hooks What to Know About
 PHP for WordPress
9. • Syntax • Variables • Operators • Conditionals • Loops • Functions • Objects PHP Language Basics
10. Learn PHP Basics
 In 4 Hours at CodeAcademy For Free codecademy.com
11. Learn PHP In 4 Hours on CodeAcademy For Free!!!
12. Ways of Writing PHP in WordPress Files
13. <?php if ( is_front_page() ) { echo “<h1>Welcome Home!</h1>”; } ?> HTML in PHP example-1.php
14. <article id=“<?php the_ID; ?>”> <h1><?php the_title(); ?></h1> </article> PHP in HTML example-2.php
15. • Syntax • Variables • Operators • Conditionals • Loops • Functions • Objects PHP Language Basics
16. Learn PHP Basics
 In 4 Hours at CodeAcademy For Free codecademy.com
17. WordPress has PHP Coding Standards https://make.wordpress.org/core/handbook/best-practices/coding-standards/php/
18. function myCustomFunction() {} function my_custom_function() {} WordPress has PHP Coding Standards if(is_single()): if ( is_single() ) : the_title(‘h2’,’h3’) the_title( ‘h2’, ‘h2’ )
19. Common PHP Theme Files
20. • header.php • footer.php • functions.php • page.php, single.php • front-page.php, home.php • category.php, archive.php Common Theme Files
21. Template Hierarchy http://wphierarchy.com/
22. Archives Custom Posts
 Miscellaneous Hierarchy Review How They Work Core Files
 Homepages Pages and Posts Template Hierarchy Course at Treehouse http://teamtreehouse.com/library/the-wordpress-template-hierarchy
23. Why Learn The Loop?
24. <?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?> <h1><?php the_title(); ?></h1> <?php the_content(); ?> <?php else: ?> <h1>Oh No!!!</h1> <p>There is no content for this page</p> <?php endif; endwhile; ?> The Loop
25. <?php $args = array( 'post_type' => ‘portfolio’, ‘category_name’ => ‘featured’, ‘posts_per_page’ => 4 ); $query = new WP_Query( $args ); ?> Custom Loops with WP_Query <?php if( $query->have_posts() ) : while( $query->have_posts() ) : $query->the_post(); ?> <h1><?php the_title(); ?></h1> <?php the_content(); ?> <?php endwhile; endif; ?>
26. <?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?> <?php get_template_part( 'content', 'page' ); ?> <?php endif; endwhile; ?> Including Files
27. Including Files get_template_part( 'content', 'page' ); Loads: content-page.php get_template_part( 'custom' ); Loads: custom.php get_template_part( ‘lib/my’ ‘file’ ); Loads: /lib/my-file.php
28. • Language Basics • WP Coding Standards • Common Files • The Loop • Template Tags • Conditionals • Hooks What to Know About
 PHP for WordPress
29. Template Tags Get You What You Need
30. • the_title() • the_content() • the_author() • the_category() • the_time() Examples of Template Tags https://codex.wordpress.org/Template_Tags
31. the_time( 'F j, Y' ); September 12, 2015 Some Template Tags Take Parameters https://codex.wordpress.org/Function_Reference/the_time the_time( ‘n/j/y’ ); 09/12/15 the_time( ‘l g:i a’ ); Saturday 9:00 am
32. Template Tag Documentation
33. One More bloginfo()
34. bloginfo( 'name' ); Site Name Get Information About WordPress Install https://codex.wordpress.org/Function_Reference/bloginfo bloginfo( ‘description’ ); Site Description bloginfo( ‘url’ ); http://siteurl.com
35. https://codex.wordpress.org/ Template_Tags
36. • Language Basics • WP Coding Standards • Common Files • The Loop • Template Tags • Conditionals • Hooks What to Know About
 PHP for WordPress
37. <?php if ( is_front_page() ): ?> <h1>Welcome Home!</h1> <?php endif; ?> Conditional Statements https://codex.wordpress.org/Conditional_Tags
38. <?php if ( is_front_page() ) { echo “<h1>Welcome Home!</h1>”; } ?> Conditional Statements https://codex.wordpress.org/Conditional_Tags
39. • is_page(), is_page( ‘about‘ ) • is_category() • is_author() • wp_is_mobile() • is_main_query() • is_woocommerce() • is_shop(), is_cart() Conditional Statements https://codex.wordpress.org/Conditional_Tags
40. Can Also Do Not !is_single()
41. if ( is_front_page() ) { } elseif ( is_page( ‘about’ ) { } else { } Multiple Conditions
42. function get_the_archive_title() { if ( is_category() ) { $title = sprintf( __( 'Category: %s' ), single_cat_title( '', false ) ); } elseif ( is_tag() ) { $title = sprintf( __( 'Tag: %s' ), single_tag_title( '', false ) ); } elseif ( is_author() ) { $title = sprintf( __( 'Author: %s' ), '<span class="vcard">' . get_the_author() . '</span>' ); } elseif ( is_year() ) { $title = sprintf( __( 'Year: %s' ), get_the_date( _x( 'Y', 'yearly archives date format' ) ) ); } elseif ( is_month() ) {
43. • Language Basics • WP Coding Standards • Common Files • The Loop • Template Tags • Conditionals • Hooks What to Know About
 PHP for WordPress
44. Hooks Let You Do Anything, Anywhere, Anytime In WordPress
45. Filters vs Actions
46. “Anything, Anywhere, Anytime” Filters }
47. “Anything, Anywhere, Anytime” Actions }
48. Filters modify something
49. Actions do something
50. A Few Examples of Actions and Filters
51. function excerpt_length_example( $length ) { return 15; } add_filter( 'excerpt_length', 'excerpt_length_example' );
52. function body_class_example( $classes ) { if( is_single() ) { foreach( get_the_category( get_the_ID() ) as $cat ) $classes[] = 'cat-' . $cat->category_nicename; } return $classes; } add_filter( 'body_class', 'body_class_example' );
53. function register_my_menus() { register_nav_menus( array( 'footer_menu' => __( 'Footer Menu', 'mytheme' ) ) ); } add_action( 'init', 'register_my_menus' );
54. function my_plugin_page() { add_options_page( 'Page Title', ‘Menu Title', 'manage_options', ‘plugin-slug', ‘my_plugin_page_init’ ); } add_action( 'admin_menu' , 'my_plugin_page' );
55. function publish_post_to_slack( ) { // Connect to Slack API } add_action( 'save_post', ‘publish_post_to_slack’ );
56. http://codex.wordpress.org/Plugin_API/Filter_Reference http://codex.wordpress.org/Plugin_API/Action_Reference
57. http://codex.wordpress.org/Plugin_API/Action_Reference Runtime
58. Where to Learn All of This, Again
59. Language Basics CodeAcademy
60. WP Coding Standards make.wordpress.org
61. Common Files wphierarchy.com
62. The Loop codex.wordpress.org/The_Loop
63. Template Tags codex.wordpress.org/Template_Tags
64. Conditional Tags codex.wordpress.org/Conditional_Tags
65. Hooks Treehouse Hooks Course
66. Be Practical In Your Learning
67. Zac Gordon wp.zacgordon.com @zgordon https://teamtreehouse.com/learn/wordpress