One home per rule: error bodies, mime types, asset paths, ordering

Four small duplications, each of which had already drifted or was one edit away
from it.

**The JSON error body.** The host's `ApiController` was a line-by-line copy of
the engine's four `rescue_from` blocks plus `resolve_mime`. It is a
`WarpEngine::ApiErrorRendering` concern now, included by both, so "what a
failure looks like on the wire" is decided once.

**Mime resolution.** The same three lines lived in the engine's API controller
and the host's. `WarpEngine::Storage.mime_for` owns it — next to the adapter
that hands out the files.

**Finding the asset behind a path.** `DownloadService` and `FileService` each
escaped `%` and `_` by hand and ran their own `LIKE` — the second one without
the exact-match attempt the first one had. `ReleaseAsset.for_relative_path` is
the one lookup: the absolute path first, then a suffix match anchored at `/`
rather than the old `%path%`, which could match a different file whose name
merely contained this one. Two now-unreachable helpers
(`DownloadService.base_path`, `FileService.base_path`) go with it.

**Ordering.** `PlatformLink` and `SoftwareImage` ordered inside their
`default_scope`, which leaks into every association and aggregate — the proof
was already in the tree: `admin/images.rb` had to write
`SoftwareImage.unscope(:order).distinct.pluck(:image_id)`, because MySQL will
not order a DISTINCT by a column it does not select. Ordering is a scope you
ask for now (`ordered`), the two places that need it ask (`for_platform`, the
`software_images` association, so the API's image order is unchanged), and the
`unscope` is gone.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

app/controllers/concerns/warp_engine/api_error_rendering.rb

@@ -0,0 +1,28 @@
+module WarpEngine
+  module ApiErrorRendering
+    extend ActiveSupport::Concern
+
+    included do
+      rescue_from StandardError do |e|
+        Rails.logger.error("[#{self.class.name}] #{e.class}: #{e.message}")
+        render json: { error: "Internal server error" }, status: :internal_server_error
+      end
+
+      rescue_from ActiveRecord::RecordNotFound do
+        render json: { error: "Not found" }, status: :not_found
+      end
+
+      rescue_from Errno::ENOENT do
+        render json: { error: "Not found" }, status: :not_found
+      end
+
+      rescue_from ArgumentError do |e|
+        render json: { error: e.message }, status: :bad_request
+      end
+    end
+
+    private
+
+    def resolve_mime(path) = WarpEngine::Storage.mime_for(path)
+  end
+end

app/controllers/warp_engine/api_controller.rb

@@ -7,25 +7,9 @@ module WarpEngine
 
     before_action :set_version_header
 
+    include WarpEngine::ApiErrorRendering
     include WarpEngine::SubjectAuthentication
 
-    rescue_from StandardError do |e|
-      Rails.logger.error("[#{self.class.name}] #{e.class}: #{e.message}")
-      render json: { error: "Internal server error" }, status: :internal_server_error
-    end
-
-    rescue_from ActiveRecord::RecordNotFound do |e|
-      render json: { error: "Not found" }, status: :not_found
-    end
-
-    rescue_from Errno::ENOENT do |e|
-      render json: { error: "Not found" }, status: :not_found
-    end
-
-    rescue_from ArgumentError do |e|
-      render json: { error: e.message }, status: :bad_request
-    end
-
     rescue_from WarpEngine::DownloadService::Denied do
       render json: { error: "Forbidden" }, status: :forbidden
     end
@@ -33,13 +17,7 @@ module WarpEngine
     private
 
     def set_version_header
-
       response.headers["WarpEngine-Version"] = WarpEngine::VERSION
     end
-
-    def resolve_mime(path)
-      ext = File.extname(path.to_s).delete_prefix(".")
-      Mime::Type.lookup_by_extension(ext) || "application/octet-stream"
-    end
   end
 end

app/models/warp_engine/release_asset.rb

@@ -13,6 +13,11 @@ module WarpEngine
 
     default_scope { where(deleted_at: nil) }
 
+    def self.for_relative_path(relative)
+      absolute = File.join(WarpEngine.config.file_container_path, relative.to_s)
+      find_by(path: absolute) || where("path LIKE ?", "%/#{sanitize_sql_like(relative.to_s)}").first
+    end
+
     def self.ransackable_attributes(auth_object = nil)
       %w[created_at deleted_at id kind path release_id updated_at]
     end

app/models/warp_engine/software_image.rb

@@ -13,7 +13,7 @@ module WarpEngine
 
     before_save :unset_other_defaults, if: -> { is_default? && is_default_changed? }
 
-    default_scope { order(:position) }
+    scope :ordered, -> { order(:position) }
 
     def self.ransackable_attributes(auth_object = nil)
       %w[created_at id image_id is_default position software_id updated_at]

app/services/warp_engine/download_service.rb

@@ -3,14 +3,6 @@ module WarpEngine
 
     class Denied < StandardError; end
 
-    def self.container_base
-      WarpEngine.config.file_container_path
-    end
-
-    def self.base_path
-      Pathname.new(container_base).realpath
-    end
-
     def locate(path:, ip:, user_agent:, referer:, subject: nil, request: nil)
       relative = path.to_s
       return nil unless storage.file?(relative)
@@ -52,9 +44,7 @@ module WarpEngine
     end
 
     def find_asset(relative)
-      escaped = relative.gsub("%", "\\%").gsub("_", "\\_")
-      WarpEngine::ReleaseAsset.find_by(path: File.join(self.class.container_base, relative)) ||
-        WarpEngine::ReleaseAsset.where("path LIKE ?", "%#{escaped}%").first
+      WarpEngine::ReleaseAsset.for_relative_path(relative)
     end
 
     def log_download(relative, asset:, ip:, user_agent:, referer:, subject:)

app/services/warp_engine/file_service.rb

@@ -1,10 +1,6 @@
 module WarpEngine
   class FileService
 
-    def self.base_path
-      Pathname.new(WarpEngine.config.file_container_path).realpath
-    end
-
     def show(input, subject: nil)
       relative = input.path.to_s
 
@@ -28,7 +24,7 @@ module WarpEngine
 
       return WarpEngine::Access::Grant::OPEN if WarpEngine::AccessPolicy.open?
 
-      asset = WarpEngine::ReleaseAsset.where("path LIKE ?", "%#{relative.gsub('%', '\\%').gsub('_', '\\_')}%").first
+      asset = WarpEngine::ReleaseAsset.for_relative_path(relative)
       grant = WarpEngine.access_policy.authorize_download(asset: asset, subject: subject, request: nil)
       raise WarpEngine::DownloadService::Denied if grant.nil?
 

lib/warp_engine/storage.rb

@@ -43,6 +43,11 @@ module WarpEngine
     end
 
     class << self
+      def mime_for(path)
+        ext = File.extname(path.to_s).delete_prefix(".")
+        Mime::Type.lookup_by_extension(ext) || "application/octet-stream"
+      end
+
       def adapter
         configured = WarpEngine.config.storage_adapter
 

spec/models/platform_link_spec.rb

@@ -28,11 +28,21 @@ RSpec.describe WarpEngine::PlatformLink, type: :model do
       expect(WarpEngine::PlatformLink.all).to eq([active])
     end
 
-    it "orders by position" do
+    it "does not order: ordering is asked for, not inherited" do
       second = create(:platform_link, position: 2)
       first  = create(:platform_link, position: 1)
 
-      expect(WarpEngine::PlatformLink.all).to eq([first, second])
+      expect(WarpEngine::PlatformLink.ordered).to eq([ first, second ])
+      expect(WarpEngine::PlatformLink.all.to_sql).not_to include("ORDER BY")
+    end
+  end
+
+  describe ".ordered" do
+    it "is what .for_platform uses, so the API keeps its link order" do
+      second = create(:platform_link, platform: "tic80", position: 2)
+      first  = create(:platform_link, platform: "tic80", position: 1)
+
+      expect(WarpEngine::PlatformLink.for_platform("tic80")).to eq([ first, second ])
     end
   end