README

Comprehensive sitemaps for your WordPress.com VIP site. Joint collaboration between Metro.co.uk, WordPress.com VIP, Alley Interactive, Maker Media, 10up, and others.

How It Works

Sitemap Data Storage

• One post type entry for each date.
• Sitemap XML is generated and stored in meta. This has several benefits:
• Avoid memory and timeout problems when rendering heavy sitemap pages with lots of posts.
• Older archives that are unlikely to change can be served up faster since we're not building them on-demand.
• Archive pages are rendered on-demand.

Sitemap Generation

We want to generate the entire sitemap catalogue async to avoid running into timeout and memory issues.

Here's how the defualt WP-Cron approach works:

• Get year range for content.
• Store these years in options table.
• Kick off a cron event for the first year.
• Calculate the months to process for that year and store in an option.
• Kick off a cron event for the first month in the year we're processing.
• Calculate the days to process for that year and store in an option.
• Kick off a cron event for the first day in the month we're processing.
• Generate the sitemap for that day.
• Find the next day to process and repeat until we run out of days.
• Move on to the next month and repeat.
• Move on to next year when we run out of months.

CLI Commands

The plugin ships with a bunch of wp-cli commands to simplify sitemap creation:

$ wp msm-sitemap
usage: wp msm-sitemap generate-sitemap
   or: wp msm-sitemap generate-sitemap-for-year
   or: wp msm-sitemap generate-sitemap-for-year-month
   or: wp msm-sitemap generate-sitemap-for-year-month-day
   or: wp msm-sitemap recount-indexed-posts

See 'wp help msm-sitemap <command>' for more information on a specific command.

Filtering Sitemap URLs

If you need to filter the URLs displayed in a sitemap created via the Comprehensive Sitemap plugin, there are two considerations. First, if you are filtering the individual sitemaps, which display the URLs to the articles published on a specific date, you can use the msm_sitemap_entry hook to filter the URLs. An example for a reverse-proxy situation is below:

function example_filter_msm_sitemap_entry( $url ) {
    $location = str_replace( 'example.wordpress.com', 'example.com/blog', $url->loc );
    $url->loc = $location;
    return $url;
}
add_filter( 'msm_sitemap_entry', 'example_filter_msm_sitemap_entry', 10, 1 );

Second, if you are filtering the root sitemap, which displays the URLs to the individual sitemaps by date, you will need to filter the home_url directly. There is no plugin-specific hook to filter the URLs on the root sitemap.

Filter Sitemap Index

Use the msm_sitemap_index filter to exclude daily sitemaps from the index based on date.

add_filter( 'msm_sitemap_index', function( $sitemaps ) {
    $reference_date = strtotime( '2017-09-09' );

    return array_filter( $sitemaps, function ( $date ) use ( $reference_date ) {
        return ( $reference_date < strtotime( $date ) );
    } );
} );