WordPress Slack Notifications

A simple way to send Slack notifications from WordPress.

Setup

• Create a Slack bot for your workspace (Make sure your bot has the chat:write and chat:write.customize scopes)
• Copy the "OAuth Tokens for Your Workspace" value and define it in wp-config.php for your site: define( 'RH_SLACKBOT_TOKEN', '<your token goes here>' );
• Upload and activate class-rh-slack.php as a plugin or include it from your theme's functions.php file

$file = get_template_directory() . '/class-rh-slack.php';
if ( file_exists( $file ) ) {
	require_once $file;
}

How do I send a Slack message?

Call the send_message() method of the RH_Slack class. Pass a message and arguments that get sent to the Slack API. See https://api.slack.com/methods/chat.postMessage

$message = 'Howdy :face_with_cowboy_hat: ';
$args = array(
    'username'   => 'Matt Mullenweg',
    'channel'    => 'general',
    'icon_emoji' => ':horse:',
);
RH_Slack::send_message( $message, $args );

What type of Slack notfications happen automatically?

When a post type that supports Slack notifications performs certian actions a Slack notfication will be sent. We hook into the WordPress action transition_post_status and compare statuses to determine what type of noticiation to send. This includes when a post is:

• Published
• Unpublished
• Scheduled
• Unscheduled
• Trashed
• Updated

Examples

Published

When a post status changes to publish from any other status

Links to the published post

Unpublished

When a post status changes to draft from publish

Links to the edit screen of the post

Scheduled

When a post status changes to future from another status that is not future

Links to the scheduled post and includes link to timeanddate.com to convert publish time to timezones for Los Angeles, New York, and Paris (Example)

Unscheduled

When a post status changes to anything except publish or future from future

Links to the edit screen of the post

Trashed

When a post status changes to trash from publish

Links to the trashed posts screen for the post type

Updated

When a post status changes to publish from publish and there is non-empty $_POST data sent to the server

(Why do we need to check if $_POST is not empty? See WordPress/gutenberg#15094 (comment))

Links to the updated post and includes a link to the post revision screen in WP Admin

How do I enable post types to support Slack notifications?

1. Add slack-notifications to the supports argument when registering your post type
2. Hook in to the filter rh/slack/notification_post_types and apend post type key(s) to the array

Non-Production Environments Safety Check

There is a safety in place to ensure Slack notifications don't get sent in non-production environments. See the line add_filter( 'rh/slack/send_message/args', array( $this, 'filter_rh_slack_send_message_args' ) ); to disable this. This filter sets the channel where all Slack notifications go to as #test-alerts instead of the usual production channels.

Filters

rh/slack/notification_post_types

Modify which post types support Slack notifications.

Example:

function ilter_rh_slack_notification_post_types( $post_types = array() ) {
    // Enable Slack notification whenever the book post type content is modified
    $post_types[] = 'book';
    return $post_types;
}
add_filter( 'rh/slack/notification_post_types', 'filter_rh_slack_notification_post_types' );

rh/slack/post_notification/message

Modify the Slack message before the notification is sent.

Example:

function filter_rh_slack_post_notification_message( $message = '', $new_status = '', $old_status = '', $post ) {
    // Don't send a post updated Slack notification
    if ( $new_status = 'publish' && $old_status = 'publish' ) {
        $message = ''; // Returning an empty string cancels sending the message
    }

    // Change the Slack message when a post is scheduled
    if ( $new_status === 'future' && $old_status !== 'future' ) {
        $the_post_title = get_the_title( $post );
		$the_post_title = html_entity_decode( $the_post_title );
		$the_permalink  = get_permalink( $post );
        $message        = "<$the_permalink|$the_post_title> has been scheduled";
    }

    return $message;
}
add_filter( 'rh/slack/post_notification/message', 'filter_rh_slack_post_notification_message' );

rh/slack/post_notification/args

Modify the Slack arguments before a notification is sent.

Example:

function filter_rh_slack_post_notification_args( $slack_args = array(), $new_status = '', $old_status = '', $post ) {
    // Change the icon for when a post is trashed
    if ( $new_status === 'trash' && $old_status === 'publish' ) {
        $slack_args['icon_emoji'] = ':poop:';
    }

    // Change the Slack bot username when the post type is Transformers
    if ( $post->post_type === 'transformers' ) {
        $slack_args['username'] = 'Optimus Prime';
    }
    return $slack_args;
}
add_filter( 'rh/slack/post_notification/args', 'filter_rh_slack_post_notification_args' );

rh/slack/send_message/args

Modify the Slack arguments before any Slack message is sent. This comes in handy when you use the RH_Slack::send_message() method or you want to ensure Slack messages don't get sent to public channels when you're testing.

Example:

function filter_rh_slack_send_message_args( $slack_args = array() ) {
    // If the environemnt is 'development' send all Slack messages to the 'dev-alerts' channel and name the bot 'Dev Bot'
    if ( wp_get_environment_type() === 'development' ) {
        $slack_args['channel']  = 'dev-alerts';
        $slack_args['username'] = 'Dev Bot';
    }
    return $slack_args;
}
add_filter( 'rh/slack/send_message/args', 'filter_rh_slack_send_message_args' );