From a098ea43bb821b08e6ed0644bd80f494fa142a1b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A2u=20Cao?= <raucao@kosmos.org>
Date: Wed, 14 May 2025 15:39:50 +0400
Subject: [PATCH] Add avatar URL to Webfinger when available

---
 app/controllers/webfinger_controller.rb | 14 +++++++++
 app/helpers/application_helper.rb       | 11 +++++--
 spec/requests/webfinger_spec.rb         | 40 +++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/app/controllers/webfinger_controller.rb b/app/controllers/webfinger_controller.rb
index 7b28719..a8e00f7 100644
--- a/app/controllers/webfinger_controller.rb
+++ b/app/controllers/webfinger_controller.rb
@@ -33,6 +33,10 @@ class WebfingerController < WellKnownController
       links: []
     }
 
+    if @user.avatar.attached?
+      jrd[:links] += avatar_link
+    end
+
     if Setting.mastodon_enabled && @user.service_enabled?(:mastodon)
       # https://docs.joinmastodon.org/spec/webfinger/
       jrd[:aliases] += mastodon_aliases
@@ -47,6 +51,16 @@ class WebfingerController < WellKnownController
     jrd
   end
 
+  def avatar_link
+    [
+      {
+        rel: "http://webfinger.net/rel/avatar",
+        type: @user.avatar.content_type,
+        href: helpers.image_url_for(@user.avatar)
+      }
+    ]
+  end
+
   def mastodon_aliases
     [
       "#{Setting.mastodon_public_url}/@#{@user.cn}",
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index a43b13e..c166e06 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -16,8 +16,15 @@ module ApplicationHelper
   end
 
   def image_url_for(attachment)
-    if Setting.s3_enabled?
-      s3_image_url(attachment)
+    return s3_image_url(attachment) if Setting.s3_enabled?
+
+    if attachment.record.is_a?(User) && attachment.name == "avatar"
+      hash, format = attachment.blob.filename.to_s.split(".", 2)
+      user_avatar_url(
+        username: attachment.record.cn,
+        hash: hash,
+        format: format
+      )
     else
       Rails.application.routes.url_helpers.rails_blob_path(attachment, only_path: true)
     end
diff --git a/spec/requests/webfinger_spec.rb b/spec/requests/webfinger_spec.rb
index 285c146..a37d3cb 100644
--- a/spec/requests/webfinger_spec.rb
+++ b/spec/requests/webfinger_spec.rb
@@ -18,6 +18,46 @@ RSpec.describe "WebFinger", type: :request do
       })
     end
 
+    describe "Avatar" do
+      context "not available" do
+        it "does not include an avatar link" do
+          get "/.well-known/webfinger?resource=acct%3Atony%40kosmos.org"
+          expect(response).to have_http_status(:ok)
+          res = JSON.parse(response.body)
+
+          link = res["links"].find{|l| l["rel"] == "http://webfinger.net/rel/avatar"}
+          expect(link).to be_nil
+        end
+      end
+
+      context "available" do
+        let(:fixture_path) { Rails.root.join("spec/fixtures/files/taipei.jpg") }
+        let(:img_data) { File.read(fixture_path) }
+        let(:img_hash) { Digest::SHA256.hexdigest(img_data) }
+
+        before do
+          ActiveStorage::Blob.create_and_upload!(
+            io: File.open(fixture_path),
+            filename: "#{img_hash}.jpg",
+            content_type: "image/jpeg"
+          ).tap do |blob|
+            user.avatar.attach(blob)
+          end
+        end
+
+        it "includes a public avatar link" do
+          get "/.well-known/webfinger?resource=acct%3Atony%40kosmos.org"
+          expect(response).to have_http_status(:ok)
+          res = JSON.parse(response.body)
+
+          link = res["links"].find { |l| l["rel"] == "http://webfinger.net/rel/avatar" }
+          expect(link).to be_present
+          expect(link["type"]).to eq("image/jpeg")
+          expect(link["href"]).to match(%r{users/tony/avatars/#{img_hash}.jpg})
+        end
+      end
+    end
+
     describe "Mastodon entries" do
       context "Mastodon available" do
         it "includes the Mastodon aliases and links for the user" do