handbook/how-to/how-to-create-custom-plugins.md

How to create a custom plugin

If you want to create your plugins, WP-CLI has a powerful scaffold command that allows us to generate starter code. In this guide we will see how to generate starter code for a basic plugin.

Step 1 - Scaffold the plugin files

The following command uses several options to lets us specify the plugin slug, its name, description, author name and uri as well as the plugin uri. You can replace the values passed to the options below to customize the plugin based on your needs.

    $ wp scaffold plugin wpcli-demo-plugin --plugin_name="WP-CLI Demo Plugin" --plugin_description="This is a wp-cli demo plugin" --plugin_author=wp-cli --plugin_author_uri="https://wp-cli.org" --plugin_uri="https://plugins.wp-cli.org/demo-plugin"
    Success: Created test files.

The above command generates a new folder called wpcli-demo-plugin in the plugins directory, with files such as:

• wpcli-demo-plugin.php
• readme.txt
• package.json
• .gitignore
• .editorconfig

Unless you use the --skip-tests flag, test-related files are generated too. These include:

• phpunit.xml.dist is the configuration file for PHPUnit.
• A CI configuration file. Use --ci=<provider> to select a supported CI provider.
• bin/install-wp-tests.sh configures the WordPress test suite and a test database.
• tests/bootstrap.php is the file that makes the current plugin active when running the test suite.
• tests/test-sample.php is a sample file containing test cases.
• .phpcs.xml.dist is a collection of PHP_CodeSniffer rules.

Step 2 - create a custom post type:

We can now use the scaffold command again to add a custom post type inside our new plugin using the wp scaffold post-type command.

    $ wp scaffold post-type books --label=Book --textdomain=wpcli-demo-plugin --dashicon=dashicons-book-alt --plugin=wpcli-demo-plugin
    Success: Created '/wpcli-demo-plugin/post-types/books.php'.

Step 3 - Write code inside the main file:

The main plugin file wpcli-demo-plugin.php is the starting point that we can use to write our plugin logic.

Inside the main plugin file lets now reference the new post type we just created.

Open in your favourite text editor the file wpcli-demo-plugin.php and under the line saying "your code starts here" add the following:

\\Your code starts here.
require('post-types/books.php');

Step 4 - Activate the plugin

You can now use two wp-cli commands to check the list of plugins and activate your newly created plugin. wp plugin list and wp plugin activate. The first command lists all plugins installed while the second activates a given plugin.

    $ wp plugin list
    +-------------------+----------+-----------+---------+
    | name              | status   | update    | version |
    +-------------------+----------+-----------+---------+
    | akismet           | inactive | available | 4.1.5   |
    | hello             | inactive | none      | 1.7.2   |
    | wpcli-demo-plugin | inactive | none      | 0.1.0   |
    +-------------------+----------+-----------+---------+

From the list above we can see that our plugin wpcli-demo-plugin is inactive. Let's enable it using the other command.

    $ wp plugin activate wpcli-demo-plugin
    Plugin 'wpcli-demo-plugin' activated.
    Success: Activated 1 of 1 plugins.

Our plugin is now active. We can visit the WordPress admin panel and start using our books custom post type.