1 files changed, 43 insertions, 0 deletions
diff --git a/app/controllers/well_known/webfinger_controller.rb b/app/controllers/well_known/webfinger_controller.rb
new file mode 100644
index 000000000..1a8ef5f90
--- /dev/null
+++ b/app/controllers/well_known/webfinger_controller.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module WellKnown
+  class WebfingerController < ApplicationController
+    def show
+      @account = Account.find_local!(username_from_resource)
+      @canonical_account_uri = @account.to_webfinger_s
+      @magic_key = pem_to_magic_key(@account.keypair.public_key)
+
+      respond_to do |format|
+        format.xml  { render content_type: 'application/xrd+xml' }
+        format.json { render content_type: 'application/jrd+json' }
+      end
+    rescue ActiveRecord::RecordNotFound
+      head 404
+    end
+
+    private
+
+    def username_from_resource
+      WebfingerResource.new(resource_param).username
+    end
+
+    def pem_to_magic_key(public_key)
+      modulus, exponent = [public_key.n, public_key.e].map do |component|
+        result = []
+
+        until component.zero?
+          result << [component % 256].pack('C')
+          component >>= 8
+        end
+
+        result.reverse.join
+      end
+
+      (['RSA'] + [modulus, exponent].map { |n| Base64.urlsafe_encode64(n) }).join('.')
+    end
+
+    def resource_param
+      params.require(:resource)
+    end
+  end
+end