Add assets:regenerate_variants rake task

Regenerates ImageMagick variants from each asset's stored original --
needed because assets uploaded before :headline existed in
FileAttachment::STYLES never had that file generated, producing a 404
rather than a distorted image. Supports ASSET_ID=N scoping so a single
asset can be tested before committing to a full, expensive sweep
across everything.

Doesn't touch the separate, still-open problem of :headline's forced
non-uniform stretch (460x250!) -- this task faithfully regenerates
whatever geometry the style defines, correctly. Fixing the distortion
itself is its own, later piece.

1 files changed, 19 insertions, 0 deletions

diff --git a/lib/tasks/assets.rake b/lib/tasks/assets.rake
new file mode 100644
index 0000000..563dfad
--- /dev/null
+++ b/lib/tasks/assets.rake
@@ -0,0 +1,19 @@
+namespace :assets do
+  desc "Regenerate ImageMagick variants for every image asset from its stored original -- rerun whenever a new style is added to FileAttachment::STYLES after assets already exist. Scope to one asset first with ASSET_ID=123."
+  task :regenerate_variants => :environment do
+    scope = Asset.images
+    scope = scope.where(id: ENV["ASSET_ID"]) if ENV["ASSET_ID"].present?
+
+    scope.find_each do |asset|
+      original_path = asset.send(:file_path, :original)
+
+      unless File.exist?(original_path)
+        puts "Skipping Asset##{asset.id} (#{asset.name}) -- no original file at #{original_path}"
+        next
+      end
+
+      asset.send(:generate_variants, original_path)
+      puts "Regenerated variants for Asset##{asset.id} (#{asset.name})"
+    end
+  end
+end