HTTP_HOST warnings when using WP-CLI

This redirect plugin does not know how to “get out of the way” when commands are being run from the WordPress CLI (wp-cli). For example, if this plugin is active and you execute wp post list | count from the command line, you will see this response before the actual count:

PHP Warning:  Undefined array key "HTTP_HOST" in ./wp-content/plugins/quick-pagepost-redirect-plugin/page_post_redirect_plugin.php on line 2053
Warning: Undefined array key "HTTP_HOST" in ./wp-content/plugins/quick-pagepost-redirect-plugin/page_post_redirect_plugin.php on line 2053
PHP Warning:  Undefined array key "HTTP_HOST" in ./wp-content/plugins/quick-pagepost-redirect-plugin/page_post_redirect_plugin.php on line 2061
Warning: Undefined array key "HTTP_HOST" in ./wp-content/plugins/quick-pagepost-redirect-plugin/page_post_redirect_plugin.php on line 2061

This is because the plugin assumes that $_SERVER includes an item with the key HTTP_HOST, which is not true when WordPress is running from the command line (and also not true in a number of other cases).

At a minimum, this command should check with array_key_exists() before trying to use the HTTP_HOST key.

Better yet, the plugin should probably use the WordPress get_site_url() call to determine the host information instead of the $_SERVER information.

Best, the plugin should notice that it is being run from the CLI (check if ( defined( 'WP_CLI' ) && WP_CLI ) {...}) before it takes certain actions that just are not needed when running from the command line.