/.well-known/

This plugin enables “Well-Known URIs” support for WordPress (RFC 5785: http://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 http://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.

1. Upload the well-known-folder to the /wp-content/plugins/ directory
2. Activate the plugin through the Plugins menu in WordPress
3. …and that’s it 🙂

How can I define a well-known uri?

Set a callback for an URI (/.well-known/robots.txt). The action is a combination of well_known_ and the file-name, in this case the hook must look like

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

Print robots.txt:

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

  exit;
}

Is there an implementation where I can write off?

Yes, you can find an example plugin, which defines a well-known-uri,
here: https://wordpress.org/extend/plugins/host-meta/

0.6.2

• bug fix

0.6.0

• refactored the code

0.5.1

• fixed some php-warnings

0.5

• better action/filter

0.4

• some improvements for host-meta (jrd)

0.3

• adding well-known uris a bit more wordpress-like

0.2.1.1

• Ooops, copy&paste bug

0.2.1

• Forgot to flush the rewrite rules

0.2

• Better doku

0.1

• Initial release