Fix avatar and header issues by using custom geometry detector (#6515)

* Fix avatar and header issues by using custom geometry detector

Revert a part of #6508. The file passed to dynamic styles method
was not actually a file, but an instance of Paperclip::Attachment,
which broke all styles by always returning {} from the method.

One problem with GIF avatars was that Paperclip::GeometryDetector
reported wrong dimensions for them, e.g. 120x120 GIF avatar would
for some reason be detected as 120x53. By writing our own geometry
parser, we can use FastImage, which also happens to be faster than
ImageMagick, to detect image dimensions, which are also correct.

Unfortunately, this PR does not implement skipping a `convert`
entirely if the dimensions are already correct, as I found no easy
way to write that behaviour into Paperclip without rewriting the
Paperclip::Thumbnail class.

* Only invoke convert if dimension or format needs to be changed

Gemfile

@@ -40,6 +40,7 @@ gem 'omniauth', '~> 1.2'
 
 gem 'doorkeeper', '~> 4.2'
 gem 'fast_blank', '~> 1.0'
+gem 'fastimage'
 gem 'goldfinger', '~> 2.1'
 gem 'hiredis', '~> 0.6'
 gem 'redis-namespace', '~> 1.5'

Gemfile.lock

@@ -185,6 +185,7 @@ GEM
     faraday (0.14.0)
       multipart-post (>= 1.2, < 3)
     fast_blank (1.0.0)
+    fastimage (2.1.1)
     ffi (1.9.18)
     fog-core (1.45.0)
       builder
@@ -641,6 +642,7 @@ DEPENDENCIES
   fabrication (~> 2.18)
   faker (~> 1.7)
   fast_blank (~> 1.0)
+  fastimage
   fog-core (~> 1.45)
   fog-local (~> 0.4)
   fog-openstack (~> 0.1)

app/lib/fast_geometry_parser.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class FastGeometryParser
+  def self.from_file(file)
+    width, height = FastImage.size(file.path)
+
+    raise Paperclip::Errors::NotIdentifiedByImageMagickError if width.nil?
+
+    Paperclip::Geometry.new(width, height)
+  end
+end

app/models/concerns/account_avatar.rb

@@ -7,15 +7,9 @@ module AccountAvatar
 
   class_methods do
     def avatar_styles(file)
-      styles   = {}
-      geometry = Paperclip::Geometry.from_file(file)
-
-      styles[:original] = '120x120#' if geometry.width != geometry.height || geometry.width > 120 || geometry.height > 120
-      styles[:static]   = { format: 'png', convert_options: '-coalesce' } if file.content_type == 'image/gif'
-
+      styles = { original: { geometry: '120x120#', file_geometry_parser: FastGeometryParser } }
+      styles[:static] = { format: 'png', convert_options: '-coalesce', file_geometry_parser: FastGeometryParser } if file.content_type == 'image/gif'
       styles
-    rescue Paperclip::Errors::NotIdentifiedByImageMagickError
-      {}
     end
 
     private :avatar_styles
@@ -23,7 +17,7 @@ module AccountAvatar
 
   included do
     # Avatar upload
-    has_attached_file :avatar, styles: ->(f) { avatar_styles(f) }, convert_options: { all: '-strip' }
+    has_attached_file :avatar, styles: ->(f) { avatar_styles(f) }, convert_options: { all: '-strip' }, processors: [:lazy_thumbnail]
     validates_attachment_content_type :avatar, content_type: IMAGE_MIME_TYPES
     validates_attachment_size :avatar, less_than: 2.megabytes
   end

app/models/concerns/account_header.rb

@@ -7,15 +7,9 @@ module AccountHeader
 
   class_methods do
     def header_styles(file)
-      styles   = {}
-      geometry = Paperclip::Geometry.from_file(file)
-
-      styles[:original] = '700x335#' unless geometry.width == 700 && geometry.height == 335
-      styles[:static]   = { format: 'png', convert_options: '-coalesce' } if file.content_type == 'image/gif'
-
+      styles = { original: { geometry: '700x335#', file_geometry_parser: FastGeometryParser } }
+      styles[:static] = { format: 'png', convert_options: '-coalesce', file_geometry_parser: FastGeometryParser } if file.content_type == 'image/gif'
       styles
-    rescue Paperclip::Errors::NotIdentifiedByImageMagickError
-      {}
     end
 
     private :header_styles
@@ -23,7 +17,7 @@ module AccountHeader
 
   included do
     # Header upload
-    has_attached_file :header, styles: ->(f) { header_styles(f) }, convert_options: { all: '-strip' }
+    has_attached_file :header, styles: ->(f) { header_styles(f) }, convert_options: { all: '-strip' }, processors: [:lazy_thumbnail]
     validates_attachment_content_type :header, content_type: IMAGE_MIME_TYPES
     validates_attachment_size :header, less_than: 2.megabytes
   end

app/models/media_attachment.rb

@@ -32,7 +32,18 @@ class MediaAttachment < ApplicationRecord
   IMAGE_MIME_TYPES = ['image/jpeg', 'image/png', 'image/gif'].freeze
   VIDEO_MIME_TYPES = ['video/webm', 'video/mp4'].freeze
 
-  IMAGE_STYLES = { original: '1280x1280>', small: '400x400>' }.freeze
+  IMAGE_STYLES = {
+    original: {
+      geometry: '1280x1280>',
+      file_geometry_parser: FastGeometryParser,
+    },
+
+    small: {
+      geometry: '400x400>',
+      file_geometry_parser: FastGeometryParser,
+    },
+  }.freeze
+
   VIDEO_STYLES = {
     small: {
       convert_options: {
@@ -167,16 +178,16 @@ class MediaAttachment < ApplicationRecord
   end
 
   def image_geometry(file)
-    geo = Paperclip::Geometry.from_file file
+    width, height = FastImage.size(file.path)
+
+    return {} if width.nil?
 
     {
-      width:  geo.width.to_i,
-      height: geo.height.to_i,
-      size: "#{geo.width.to_i}x#{geo.height.to_i}",
-      aspect: geo.width.to_f / geo.height.to_f,
+      width:  width,
+      height: height,
+      size: "#{width}x#{height}",
+      aspect: width.to_f / height.to_f,
     }
-  rescue Paperclip::Errors::NotIdentifiedByImageMagickError
-    {}
   end
 
   def video_metadata(file)

app/models/preview_card.rb

@@ -33,7 +33,7 @@ class PreviewCard < ApplicationRecord
 
   has_and_belongs_to_many :statuses
 
-  has_attached_file :image, styles: { original: '400x400>' }, convert_options: { all: '-quality 80 -strip' }
+  has_attached_file :image, styles: { original: { geometry: '400x400>', file_geometry_parser: FastGeometryParser } }, convert_options: { all: '-quality 80 -strip' }
 
   include Attachmentable
   include Remotable
@@ -58,10 +58,11 @@ class PreviewCard < ApplicationRecord
 
     return if file.nil?
 
-    geo         = Paperclip::Geometry.from_file(file)
-    self.width  = geo.width.to_i
-    self.height = geo.height.to_i
-  rescue Paperclip::Errors::NotIdentifiedByImageMagickError
-    nil
+    width, height = FastImage.size(file.path)
+
+    return nil if width.nil?
+
+    self.width  = width
+    self.height = height
   end
 end

app/models/site_upload.rb

@@ -34,8 +34,8 @@ class SiteUpload < ApplicationRecord
 
     return if tempfile.nil?
 
-    geometry  = Paperclip::Geometry.from_file(tempfile)
-    self.meta = { width: geometry.width.to_i, height: geometry.height.to_i }
+    width, height = FastImage.size(tempfile.path)
+    self.meta = { width: width, height: height }
   end
 
   def clear_cache

config/application.rb

@@ -7,6 +7,7 @@ require 'rails/all'
 Bundler.require(*Rails.groups)
 
 require_relative '../app/lib/exceptions'
+require_relative '../lib/paperclip/lazy_thumbnail'
 require_relative '../lib/paperclip/gif_transcoder'
 require_relative '../lib/paperclip/video_transcoder'
 require_relative '../lib/mastodon/snowflake'

lib/paperclip/lazy_thumbnail.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module Paperclip
+  class LazyThumbnail < Paperclip::Thumbnail
+    def make
+      return @file unless needs_convert?
+      Paperclip::Thumbnail.make(file, options, attachment)
+    end
+
+    private
+
+    def needs_convert?
+      needs_different_geometry? || needs_different_format?
+    end
+
+    def needs_different_geometry?
+      !@target_geometry.nil? && @current_geometry.width != @target_geometry.width && @current_geometry.height != @target_geometry.height
+    end
+
+    def needs_different_format?
+      @format.present? && @current_format != @format
+    end
+  end
+end