Very incomplete first stab

1 files changed, 52 insertions, 0 deletions

diff --git a/lib/active_storage/variant.rb b/lib/active_storage/variant.rb
new file mode 100644
index 0000000000..9b9dad43da
--- /dev/null
+++ b/lib/active_storage/variant.rb
@@ -0,0 +1,52 @@
+require "active_storage/blob"
+require "mini_magick"
+
+class ActiveStorage::Variant
+  class_attribute :verifier
+
+  attr_reader :blob, :variation
+  delegate :service, to: :blob
+
+  def self.lookup(blob_key:, variation_key:)
+    new ActiveStorage::Blob.find_by!(key: blob_key), variation: verifier.verify(variation_key)
+  end
+
+  def self.encode_key(variation)
+    verifier.generate(variation)
+  end
+
+  def initialize(blob, variation:)
+    @blob, @variation = blob, variation
+  end
+
+  def url(expires_in: 5.minutes, disposition: :inline)
+    perform unless exist?
+    service.url key, expires_in: expires_in, disposition: disposition, filename: blob.filename
+  end
+
+  def key
+    verifier.generate(variation)
+  end
+
+  private
+    def perform
+      upload_variant transform(download_blob)
+    end
+
+    def download_blob
+      service.download(blob.key)
+    end
+
+    def upload_variant(variation)
+      service.upload key, variation
+    end
+
+    def transform(io)
+      # FIXME: Actually do a variant based on the variation
+      File.open MiniMagick::Image.read(io).resize("500x500").path
+    end
+
+    def exist?
+      service.exist?(key)
+    end
+end