Even though this is no longer a problem for you, I decided to pursue it for purely academic reasons. I got it working by prepending rewrite rules and filtering permalinks. Note that I wouldn’t actually recommend doing this, but it’s fun to know it’s possible 🙂
function filter_post_link($permalink, $post) {
if ($post->post_type != 'post')
return $permalink;
return 'blog'.$permalink;
}
add_filter('pre_post_link', 'filter_post_link', 10, 2);
add_action( 'generate_rewrite_rules', 'add_blog_rewrites' );
function add_blog_rewrites( $wp_rewrite ) {
$wp_rewrite->rules = array(
'blog/([^/]+)/?$' => 'index.php?name=$matches[1]',
'blog/[^/]+/attachment/([^/]+)/?$' => 'index.php?attachment=$matches[1]',
'blog/[^/]+/attachment/([^/]+)/trackback/?$' => 'index.php?attachment=$matches[1]&tb=1',
'blog/[^/]+/attachment/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$' => 'index.php?attachment=$matches[1]&feed=$matches[2]',
'blog/[^/]+/attachment/([^/]+)/(feed|rdf|rss|rss2|atom)/?$' => 'index.php?attachment=$matches[1]&feed=$matches[2]',
'blog/[^/]+/attachment/([^/]+)/comment-page-([0-9]{1,})/?$' => 'index.php?attachment=$matches[1]&cpage=$matches[2]',
'blog/([^/]+)/trackback/?$' => 'index.php?name=$matches[1]&tb=1',
'blog/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$' => 'index.php?name=$matches[1]&feed=$matches[2]',
'blog/([^/]+)/(feed|rdf|rss|rss2|atom)/?$' => 'index.php?name=$matches[1]&feed=$matches[2]',
'blog/([^/]+)/page/?([0-9]{1,})/?$' => 'index.php?name=$matches[1]&paged=$matches[2]',
'blog/([^/]+)/comment-page-([0-9]{1,})/?$' => 'index.php?name=$matches[1]&cpage=$matches[2]',
'blog/([^/]+)(/[0-9]+)?/?$' => 'index.php?name=$matches[1]&page=$matches[2]',
'blog/[^/]+/([^/]+)/?$' => 'index.php?attachment=$matches[1]',
'blog/[^/]+/([^/]+)/trackback/?$' => 'index.php?attachment=$matches[1]&tb=1',
'blog/[^/]+/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$' => 'index.php?attachment=$matches[1]&feed=$matches[2]',
'blog/[^/]+/([^/]+)/(feed|rdf|rss|rss2|atom)/?$' => 'index.php?attachment=$matches[1]&feed=$matches[2]',
'blog/[^/]+/([^/]+)/comment-page-([0-9]{1,})/?$' => 'index.php?attachment=$matches[1]&cpage=$matches[2]',
) + $wp_rewrite->rules;
}