From 10129fbf57ef851ad56158529081afa05ea1c030 Mon Sep 17 00:00:00 2001
From: George Claghorn <george.claghorn@gmail.com>
Date: Thu, 9 Aug 2018 19:53:12 -0400
Subject: DRY up web image checks in ActiveStorage::Variant

---
 activestorage/app/models/active_storage/variant.rb | 42 ++++++++++++----------
 1 file changed, 24 insertions(+), 18 deletions(-)

(limited to 'activestorage/app')

diff --git a/activestorage/app/models/active_storage/variant.rb b/activestorage/app/models/active_storage/variant.rb
index 056fd2be99..239df34d81 100644
--- a/activestorage/app/models/active_storage/variant.rb
+++ b/activestorage/app/models/active_storage/variant.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "ostruct"
+
 # Image blobs can have variants that are the result of a set of transformations applied to the original.
 # These variants are used to create thumbnails, fixed-size avatars, or any other derivative image from the
 # original.
@@ -51,7 +53,7 @@
 # * {ImageProcessing::Vips}[https://github.com/janko-m/image_processing/blob/master/doc/vips.md#methods]
 # * {ruby-vips reference}[http://www.rubydoc.info/gems/ruby-vips/Vips/Image]
 class ActiveStorage::Variant
-  WEB_IMAGE_CONTENT_TYPES = %w( image/png image/jpeg image/jpg image/gif )
+  WEB_IMAGE_CONTENT_TYPES = %w[ image/png image/jpeg image/jpg image/gif ]
 
   attr_reader :blob, :variation
   delegate :service, to: :blob
@@ -95,27 +97,11 @@ class ActiveStorage::Variant
 
     def process
       blob.open do |image|
-        transform image do |output|
-          upload output
-        end
+        transform(image) { |output| upload(output) }
       end
     end
 
-
-    def filename
-      if WEB_IMAGE_CONTENT_TYPES.include?(blob.content_type)
-        blob.filename
-      else
-        ActiveStorage::Filename.new("#{blob.filename.base}.png")
-      end
-    end
-
-    def content_type
-      blob.content_type.presence_in(WEB_IMAGE_CONTENT_TYPES) || "image/png"
-    end
-
     def transform(image)
-      format = "png" unless WEB_IMAGE_CONTENT_TYPES.include?(blob.content_type)
       result = variation.transform(image, format: format)
 
       begin
@@ -128,4 +114,24 @@ class ActiveStorage::Variant
     def upload(file)
       service.upload(key, file)
     end
+
+
+    def specification
+      @specification ||=
+        if WEB_IMAGE_CONTENT_TYPES.include?(blob.content_type)
+          Specification.new \
+            filename: blob.filename,
+            content_type: blob.content_type,
+            format: nil
+        else
+          Specification.new \
+            filename: ActiveStorage::Filename.new("#{blob.filename.base}.png"),
+            content_type: "image/png",
+            format: "png"
+        end
+    end
+
+    delegate :filename, :content_type, :format, to: :specification
+
+    class Specification < OpenStruct; end
 end
-- 
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