feat/fedi-redirect (#5682)

So, this is a basic attempt at implementing the fedi redirects as described on the webpage.

Things I do not understand:

- In what format should we expect the address request to come?
- how one should determine the "location" param to be set in the header?
- What actually are the `.well-known` locations we need to redirect to the script?

Note that the php script is completely untested and almost certainly broken: this is a very rough POC

Co-authored-by: Darragh Elliott <me@delliott.net>
Reviewed-on: #5682
Co-authored-by: delliott <delliott@fsfe.org>
Co-committed-by: delliott <delliott@fsfe.org>

fsfe.org/.htaccess

@@ -331,4 +331,5 @@ RewriteRule ^about/printable(/.*)?$ /contribute/spreadtheword.html [R=301,L]
 RewriteRule ^(tools|build)(/.*)?$ - [F,L]
 # Redirect attempts to status to status.fsfe.org
 RewriteRule ^status.fsfe.org(/.*)?$     https://status.fsfe.org/ [R=301,L]
-
+# Redirect fediverse redirects to our script
+RewriteRule ^\.well-known/webfinger$ /cgi-bin/webfinger.php [L]

fsfe.org/about/people/people.en.xml

@@ -51,6 +51,7 @@
       full: Person is working 4 or 5 days a week
       part: Person is working 3 or less days a week
       freelancer: Person is working on honorary basis, no matter which salary or how long
+    <fediverse> Fediverse address of person.
   -->
   <!--
     Technical information:
@@ -323,6 +324,7 @@
     <function volunteers="web">coordinator/m</function>
     <link>/about/people/tobiasd/tobiasd.html</link>
     <avatar>tobiasd.png</avatar>
+    <fediverse handle="tobias@social.diekershoff.de">tobiasd@fsfe.org</fediverse>
   </person>
 
   <person id="dietrich">
@@ -627,6 +629,7 @@
     <link>/about/people/kirschner/kirschner.html</link>
     <avatar>kirschner.jpg</avatar>
     <employee>full/m</employee>
+    <fediverse handle="kirschner@mastodon.social">mk@fsfe.org</fediverse>
   </person>
 
   <person id="kneissl">

fsfe.org/cgi-bin/webfinger.php

@@ -0,0 +1,33 @@
+<?php
+
+$acc_request = strtolower($_GET['resource'] ?? '');
+$xml_file = $_SERVER['DOCUMENT_ROOT'].'about/people/people.en.xml';
+$people = simplexml_load_file($xml_file);
+if (false === $people) {
+    http_response_code(500);
+    echo 'ERROR: Could not load people file. Please check the path:'.$xml_file;
+
+    exit;
+}
+
+foreach ($people->xpath('//fediverse') as $fedi_elem) {
+    if ('acct:'.strval($fedi_elem) === $acc_request) {
+        // if we have a location, return it and exit
+        if (isset($fedi_elem['handle'])) {
+            // Handles are in the form <username>@<server>
+            $handle = strval($fedi_elem['handle']);
+            $handle_sections = explode('@', $handle);
+            $response = 'Location: https://'.$handle_sections[1].'/.well-known/webfinger?resource=acct:'.$handle;
+            header($response);
+
+            exit;
+        }
+        http_response_code(500);
+        echo 'ERROR: fediverse element has no location attribute.';
+
+        exit;
+    }
+}
+// No matches
+http_response_code(404);
+echo '404 matching person not found.';

fsfe.org/config.toml

@@ -1,5 +1,5 @@
 # This is a config file for a site, that cuontains necessary settings
-# 
+#
 # Sources for the website
 # All repos should be mirrored to https://git.fsfe.org/fsfe-system-hackers-mirrors
 #
@@ -11,6 +11,7 @@ file_sets = [
   { source = "/dist/jquery.min.js", target = "scripts/thirdparty/" },
   { source = "/dist/jquery.min.map", target = "scripts/thirdparty/" },
 ]
+
 [[dependencies]]
 repo = "https://git.fsfe.org/fsfe-system-hackers-mirrors/lunr.js"
 rev = "v2.3.9"
@@ -32,4 +33,4 @@ file_sets = [{ source = "/src", target = "cgi-bin/thirdparty/PHPMailer" }]
 [deployment]
 # This files contains relative paths we want to deploy even if they would be blocked by the copy_files method filtering.
 # Special case hard code pass over order items xml required by cgi script
-required_files = ["order/data/items.en.xml"]
+required_files = ["order/data/items.en.xml", "about/people/people.en.xml"]