blogroll.php

<?php

// A blogroll for WordPress
// To be used with the link manager plugin https://wordpress.org/plugins/link-manager/

// More info: https://josh.blog/2024/05/blogrolls

namespace Blogroll;

function custom_rewrite_rule() {
    add_rewrite_rule('^.well-known/recommendations.opml/?$', 'index.php?well_known_recommendations=1', 'top');
}
add_action('init', 'Blogroll\custom_rewrite_rule');

function custom_query_vars($query_vars) {
    $query_vars[] = 'well_known_recommendations';
    return $query_vars;
}
add_filter('query_vars', 'Blogroll\custom_query_vars');

function custom_template_include($template) {
    if (get_query_var('well_known_recommendations')) {
        return ABSPATH . 'wp-links-opml.php';
    }
    return $template;
}
add_filter('template_include', 'Blogroll\custom_template_include');

function add_recommendations_opml_link() {
    printf('<link rel="blogroll" type="text/xml" href="%s" />', home_url('/.well-known/recommendations.opml'));
}
add_action('wp_head', 'Blogroll\add_recommendations_opml_link');

function custom_rss_feed_item() {
    printf("\t<source:blogroll>%s</source:blogroll>\n", home_url('/.well-known/recommendations.opml'));
}
add_action('rss2_head', 'Blogroll\custom_rss_feed_item');

function blogroll_namespace() {
    echo 'xmlns:source="http://source.scripting.com/"';
}
add_action('rss2_ns', 'Blogroll\blogroll_namespace');

I think this should also add xmlns:source="http://source.scripting.com/" to the rss element to define the custom namespace. Without this RSS parsers can throw validation errors.

@ralexander-phi good catch, thanks! Should be fixed now.

I tried uploading this as a plugin to WordPress (as a .zip), but I get this error:

Unpacking the package…

Installing the plugin…

The package could not be installed. No valid plugins were found.

Plugin installation failed.

Any ideas?

Will be blogging about it in the context of sharing blogrolls if I can get it up and running, and will add you to my blogroll! :- )