/well-known-uris/

Description

This plugin enables “Well-Known URIs” support for WordPress (RFC 5785: https://tools.ietf.org/html/rfc5785).

From the RFC:

It is increasingly common for Web-based protocols to require the
discovery of policy or other information about a host (“site-wide
metadata”) before making a request. For example, the Robots
Exclusion Protocol https://www.robotstxt.org/ specifies a way for
automated processes to obtain permission to access resources;
likewise, the Platform for Privacy Preferences
tells user-agents how to discover privacy policy beforehand.

While there are several ways to access per-resource metadata (e.g.,
HTTP headers, WebDAV’s PROPFIND [RFC4918]), the perceived overhead
(either in terms of client-perceived latency and/or deployment
difficulties) associated with them often precludes their use in these
scenarios.

When this happens, it is common to designate a “well-known location”
for such data, so that it can be easily located. However, this
approach has the drawback of risking collisions, both with other such
designated “well-known locations” and with pre-existing resources.

To address this, this memo defines a path prefix in HTTP(S) URIs for
these “well-known locations”, “/.well-known/”. Future specifications
that need to define a resource for such site-wide metadata can
register their use to avoid collisions and minimise impingement upon
sites’ URI space.

You will need ‘manage_options’ capability in order to use the Settings
page for this plugin.

Installation

1. Upload the well-known-folder to the /wp-content/plugins/ directory
2. Activate the plugin through the Plugins menu in WordPress

3. If you wish to define one or more Well-Known URIs that return static output,
   go to Settings > Well-Known URIs and define them, e.g.

   Path: /.well-known/
   robots.txt
   
   Content-Type:
   text/plain; charset=utf-8
   
   URI contents:
   User-agent: *
   Allow: /
   

4. If you want to configure a Well-Known URI that returns dynamic output,
   first, edit the plugin source to define a function invoked by
   do_action for the action "well_known_uri_" + $path. That function
   will be invoked when /.well-known/${path} is requested.

FAQ

How can I define a well-known uri?

Set a callback for an URI (e.g., “/.well-known/robots.txt”),
identified by "well_known_uri_" + $path (e.g., "well_known_uri_robots.txt").

    add_action('well_known_uri_robots.txt', 'robots_txt');

In the callback, do whatever processing is appropriate, e.g.,

    function robots_txt($query) {
          header('Content-Type: text/plain; charset=' . get_option('blog_charset'), TRUE);
          echo "User-agent: *";
          echo "Allow: /";

          exit;
        }

This code defines a URI that returns static output, as shown in Step 3 above.
(For static output, you will want to use Settings > Well-Known URIs page to
avoid writing any code.)

Is there an implementation where I can write off?

Yes, you can find an example plugin, which defines a Well-Known URI,
here: https://www.ads-software.com/extend/plugins/host-meta/

Reviews

Contributors & Developers

Changelog

1.0.3

• Fork from the original — https://www.ads-software.com/plugins/well-known/ —
  many thanks to https://profiles.www.ads-software.com/pfefferle/ for the
  excellent plugin!