From 570877da3c39707c2101c3510fab1509fb8ba3e2 Mon Sep 17 00:00:00 2001
From: Sam <sam.saffron@gmail.com>
Date: Thu, 3 Jan 2019 17:07:30 +1100
Subject: [PATCH] FEATURE: store thumbnail algorithm version in optimized image
 table

Previously we had no idea what algorithm generated thumbnails, this starts tracking the version.

We also bumped up the version to force all optimized images to be generated. This is important cause we recently introduced pngquant which results in much smaller images.
---
 app/models/optimized_image.rb                 |  7 ++---
 ...3051737_add_version_to_optimized_images.rb |  5 ++++
 spec/models/optimized_image_spec.rb           | 26 +++++++++++++++++++
 3 files changed, 35 insertions(+), 3 deletions(-)
 create mode 100644 db/migrate/20190103051737_add_version_to_optimized_images.rb

diff --git a/app/models/optimized_image.rb b/app/models/optimized_image.rb
index 5e5e8e41919..5cc24846543 100644
--- a/app/models/optimized_image.rb
+++ b/app/models/optimized_image.rb
@@ -7,7 +7,7 @@ class OptimizedImage < ActiveRecord::Base
   belongs_to :upload
 
   # BUMP UP if optimized image algorithm changes
-  VERSION = 1
+  VERSION = 2
 
   def self.lock(upload_id, width, height)
     @hostname ||= `hostname`.strip rescue "unknown"
@@ -43,7 +43,7 @@ class OptimizedImage < ActiveRecord::Base
     thumbnail = find_by(upload_id: upload.id, width: width, height: height)
 
     # correct bad thumbnail if needed
-    if thumbnail && thumbnail.url.blank?
+    if thumbnail && (thumbnail.url.blank? || thumbnail.version != VERSION)
       thumbnail.destroy!
       thumbnail = nil
     end
@@ -94,7 +94,8 @@ class OptimizedImage < ActiveRecord::Base
             width: width,
             height: height,
             url: "",
-            filesize: File.size(temp_path)
+            filesize: File.size(temp_path),
+            version: VERSION
           )
 
           # store the optimized image and update its url
diff --git a/db/migrate/20190103051737_add_version_to_optimized_images.rb b/db/migrate/20190103051737_add_version_to_optimized_images.rb
new file mode 100644
index 00000000000..88d2fb99586
--- /dev/null
+++ b/db/migrate/20190103051737_add_version_to_optimized_images.rb
@@ -0,0 +1,5 @@
+class AddVersionToOptimizedImages < ActiveRecord::Migration[5.2]
+  def change
+    add_column :optimized_images, :version, :integer
+  end
+end
diff --git a/spec/models/optimized_image_spec.rb b/spec/models/optimized_image_spec.rb
index 35e95cd9be7..4c832a8f4bf 100644
--- a/spec/models/optimized_image_spec.rb
+++ b/spec/models/optimized_image_spec.rb
@@ -201,6 +201,32 @@ describe OptimizedImage do
 
   describe ".create_for" do
 
+    context "versioning" do
+      let(:filename) { 'logo.png' }
+      let(:file) { file_from_fixtures(filename) }
+
+      it "is able to update optimized images on version change" do
+        upload = UploadCreator.new(file, filename).create_for(Discourse.system_user.id)
+        optimized = OptimizedImage.create_for(upload, 10, 10)
+
+        expect(optimized.version).to eq(OptimizedImage::VERSION)
+
+        optimized_again = OptimizedImage.create_for(upload, 10, 10)
+        expect(optimized_again.id).to eq(optimized.id)
+
+        optimized.update_columns(version: nil)
+        old_id = optimized.id
+
+        optimized_new = OptimizedImage.create_for(upload, 10, 10)
+
+        expect(optimized_new.id).not_to eq(old_id)
+
+        # cleanup (which transaction rollback may miss)
+        optimized_new.destroy
+        upload.destroy
+      end
+    end
+
     it "is able to 'optimize' an svg" do
       # we don't really optimize anything, we simply copy
       # but at least this confirms this actually works