From 44239bc5d4d5c714024fa12be2a612885d09fe38 Mon Sep 17 00:00:00 2001
From: Alex Kotov <kotovalexarian@gmail.com>
Date: Wed, 10 May 2023 15:30:58 +0400
Subject: [PATCH] Webfinger example

---
 lib/diversipub/rack_app.rb | 76 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 75 insertions(+), 1 deletion(-)

diff --git a/lib/diversipub/rack_app.rb b/lib/diversipub/rack_app.rb
index ace28ff..70a16ab 100644
--- a/lib/diversipub/rack_app.rb
+++ b/lib/diversipub/rack_app.rb
@@ -19,18 +19,25 @@ module Diversipub
 
   private
 
+    # rubocop:disable Metrics/MethodLength
+
     def builder
       @builder ||= Rack::Builder.new.tap do |builder|
         builder.use Rack::Head
         builder.use Rack::ShowExceptions
         builder.use Rack::ShowStatus
         builder.use Rack::ContentLength
-        builder.use Rack::Static, **rack_static_kwargs
         builder.use Rack::Protection, except: %i[session_hijacking]
+        builder.map '/.well-known/webfinger' do
+          run Webfinger.new
+        end
+        builder.use Rack::Static, **rack_static_kwargs
         builder.run rest
       end
     end
 
+    # rubocop:enable Metrics/MethodLength
+
     def rack_static_kwargs
       @rack_static_kwargs ||= {
         cascade: true,
@@ -43,5 +50,72 @@ module Diversipub
     def rest
       @rest ||= ->(_) { [200, {}, ['Hello, World!']] }
     end
+
+    ##
+    # Webfinger endpoint.
+    #
+    class Webfinger
+      JRD_JSON = 'application/jrd+json'
+
+      ACCT_RU = 'acct:ru@causa-arcana.com'
+      ACCT_EN = 'acct:en@causa-arcana.com'
+
+      RU = {
+        subject: ACCT_RU,
+        aliases: [].freeze,
+        links: [
+          {
+            rel: 'http://webfinger.net/rel/profile-page',
+            type: 'text/html',
+            href: 'https://causa-arcana.com/ru/blog/feed.html',
+          },
+          {
+            rel: 'http://webfinger.net/rel/profile-page',
+            type: 'text/gemini; charset=utf-8',
+            href: 'gemini://causa-arcana.com/ru/blog/feed.gmi',
+          },
+        ].freeze,
+      }.freeze
+
+      EN = {
+        subject: ACCT_EN,
+        aliases: [].freeze,
+        links: [
+          {
+            rel: 'http://webfinger.net/rel/profile-page',
+            type: 'text/html',
+            href: 'https://causa-arcana.com/en/blog/feed.html',
+          },
+          {
+            rel: 'http://webfinger.net/rel/profile-page',
+            type: 'text/gemini; charset=utf-8',
+            href: 'gemini://causa-arcana.com/en/blog/feed.gmi',
+          },
+        ].freeze,
+      }.freeze
+
+      def call(env)
+        request = Rack::Request.new env
+        resource = request.params['resource']
+
+        data =
+          case resource
+          when ACCT_RU then RU
+          when ACCT_EN then EN
+          else
+            raise 'Unknown resource'
+          end
+
+        [
+          200,
+          {
+            Rack::CONTENT_TYPE => JRD_JSON,
+          },
+          [
+            data.to_json,
+          ],
+        ]
+      end
+    end
   end
 end