Class: OptimizedImage

Inherits:
ActiveRecord::Base
  • Object
show all
Includes:
HasUrl
Defined in:
app/models/optimized_image.rb

Constant Summary collapse

VERSION =

BUMP UP if optimized image algorithm changes

2
MAX_PNGQUANT_SIZE = 
500_000
MAX_CONVERT_SECONDS = 
20

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.convert_with(instructions, to, opts = {}) ⇒ Object 



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# File 'app/models/optimized_image.rb', line 318

def self.convert_with(instructions, to, opts = {})
  Discourse::Utils.execute_command(
    "nice",
    "-n",
    "10",
    *instructions,
    timeout: MAX_CONVERT_SECONDS,
  )

  allow_pngquant = to.downcase.ends_with?(".png") && File.size(to) < MAX_PNGQUANT_SIZE
  FileHelper.optimize_image!(to, allow_pngquant: allow_pngquant)
  true
rescue => e
  if opts[:raise_on_error]
    raise e
  else
    error = +"Failed to optimize image:"

    if e.message =~ /\Aconvert:([^`]+)/
      error << $1
    else
      error << " unknown reason"
    end

    Discourse.warn(
      error,
      upload_id: opts[:upload_id],
      location: to,
      error_message: e.message,
      instructions: instructions,
    )
    false
  end
end

.create_for(upload, width, height, opts = {}) ⇒ Object 



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# File 'app/models/optimized_image.rb', line 26

def self.create_for(upload, width, height, opts = {})
  return if width <= 0 || height <= 0
  return if upload.try(:sha1).blank?

  # no extension so try to guess it
  upload.fix_image_extension if (!upload.extension)

  if !upload.extension.match?(IM_DECODERS) && upload.extension != "svg"
    if !opts[:raise_on_error]
      # nothing to do ... bad extension, not an image
      return
    else
      raise InvalidAccess
    end
  end

  # prefer to look up the thumbnail without grabbing any locks
  thumbnail = find_by(upload_id: upload.id, width: width, height: height)

  # correct bad thumbnail if needed
  if thumbnail && (thumbnail.url.blank? || thumbnail.version != VERSION)
    thumbnail.destroy!
    thumbnail = nil
  end

  return thumbnail if thumbnail

  # create the thumbnail otherwise
  original_path = Discourse.store.path_for(upload)

  if original_path.blank?
    # download is protected with a DistributedMutex
    external_copy = Discourse.store.download_safe(upload)
    original_path = external_copy&.path
  end

  lock(upload.id, width, height) do
    # may have been generated since we got the lock
    thumbnail = find_by(upload_id: upload.id, width: width, height: height)

    # return the previous thumbnail if any
    return thumbnail if thumbnail

    if original_path.blank?
      Rails.logger.error("Could not find file in the store located at url: #{upload.url}")
    else
      # create a temp file with the same extension as the original
      extension = ".#{opts[:format] || upload.extension}"

      return nil if extension.length == 1

      temp_file = Tempfile.new(["discourse-thumbnail", extension])
      temp_path = temp_file.path

      target_quality =
        upload.target_image_quality(original_path, SiteSetting.image_preview_jpg_quality)
      opts = opts.merge(quality: target_quality) if target_quality
      opts = opts.merge(upload_id: upload.id)

      if upload.extension == "svg"
        FileUtils.cp(original_path, temp_path)
        resized = true
      elsif opts[:crop]
        resized = crop(original_path, temp_path, width, height, opts)
      else
        resized = resize(original_path, temp_path, width, height, opts)
      end

      if resized
        thumbnail =
          OptimizedImage.create!(
            upload_id: upload.id,
            sha1: Upload.generate_digest(temp_path),
            extension: extension,
            width: width,
            height: height,
            url: "",
            filesize: File.size(temp_path),
            version: VERSION,
          )

        # store the optimized image and update its url
        File.open(temp_path) do |file|
          url =
            Discourse.store.store_optimized_image(file, thumbnail, nil, secure: upload.secure?)
          if url.present?
            thumbnail.url = url
            thumbnail.save
          else
            Rails.logger.error(
              "Failed to store optimized image of size #{width}x#{height} from url: #{upload.url}\nTemp image path: #{temp_path}",
            )
          end
        end
      end

      # close && remove temp file
      temp_file.close!
    end

    # make sure we remove the cached copy from external stores
    external_copy&.close if Discourse.store.external?

    thumbnail
  end
end

.crop(from, to, width, height, opts = {}) ⇒ Object 



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# File 'app/models/optimized_image.rb', line 300

def self.crop(from, to, width, height, opts = {})
  optimize("crop", from, to, "#{width}x#{height}", opts)
end

.crop_instructions(from, to, dimensions, opts = {}) ⇒ Object 



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# File 'app/models/optimized_image.rb', line 241

def self.crop_instructions(from, to, dimensions, opts = {})
  ensure_safe_paths!(from, to)

  from = prepend_decoder!(from, to, opts)
  to = prepend_decoder!(to, to, opts)

  instructions = %W{
    convert
    #{from}[0]
    -auto-orient
    -gravity
    north
    -background
    transparent
    -#{thumbnail_or_resize}
    #{dimensions}^
    -crop
    #{dimensions}+0+0
    -unsharp
    2x0.5+0.7+0
    -interlace
    none
    -profile
    #{File.join(Rails.root, "vendor", "data", "RT_sRGB.icm")}
  }

  instructions << "-quality" << opts[:quality].to_s if opts[:quality]

  instructions << to
end

.downsize(from, to, dimensions, opts = {}) ⇒ Object 



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# File 'app/models/optimized_image.rb', line 304

def self.downsize(from, to, dimensions, opts = {})
  optimize("downsize", from, to, dimensions, opts)
end

.downsize_instructions(from, to, dimensions, opts = {}) ⇒ Object 



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# File 'app/models/optimized_image.rb', line 272

def self.downsize_instructions(from, to, dimensions, opts = {})
  ensure_safe_paths!(from, to)

  from = prepend_decoder!(from, to, opts)
  to = prepend_decoder!(to, to, opts)

  %W{
    convert
    #{from}[0]
    -auto-orient
    -gravity
    center
    -background
    transparent
    -interlace
    none
    -resize
    #{dimensions}
    -profile
    #{File.join(Rails.root, "vendor", "data", "RT_sRGB.icm")}
    #{to}
  }
end

.ensure_safe_paths!(*paths) ⇒ Object 



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# File 'app/models/optimized_image.rb', line 174

def self.ensure_safe_paths!(*paths)
  paths.each { |path| raise Discourse::InvalidAccess unless safe_path?(path) }
end

.lock(upload_id, width, height) ⇒ Object 



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# File 'app/models/optimized_image.rb', line 11

def self.lock(upload_id, width, height)
  @hostname ||= Discourse.os_hostname
  # note, the extra lock here ensures we only optimize one image per machine on webs
  # this can very easily lead to runaway CPU so slowing it down is beneficial and it is hijacked
  #
  # we can not afford this blocking in Sidekiq cause it can lead to starvation
  if Sidekiq.server?
    DistributedMutex.synchronize("optimized_image_#{upload_id}_#{width}_#{height}") { yield }
  else
    DistributedMutex.synchronize("optimized_image_host_#{@hostname}") do
      DistributedMutex.synchronize("optimized_image_#{upload_id}_#{width}_#{height}") { yield }
    end
  end
end

.optimize(operation, from, to, dimensions, opts = {}) ⇒ Object 



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# File 'app/models/optimized_image.rb', line 308

def self.optimize(operation, from, to, dimensions, opts = {})
  method_name = "#{operation}_instructions"

  instructions = self.public_send(method_name.to_sym, from, to, dimensions, opts)
  convert_with(instructions, to, opts)
end

.prepend_decoder!(path, ext_path = nil, opts = nil) ⇒ Object

Raises:



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# File 'app/models/optimized_image.rb', line 180

def self.prepend_decoder!(path, ext_path = nil, opts = nil)
  opts ||= {}

  # This logic is a little messy but the result of using mocks for most
  # of the image tests. The idea here is you shouldn't trust the "original"
  # path of a file to figure out its extension. However, in certain cases
  # such as generating the loading upload thumbnail, we force the format,
  # and this allows us to use the forced format in that case.
  extension = nil
  if (opts[:format] && path != ext_path)
    extension = File.extname(path)[1..-1]
  else
    extension = File.extname(opts[:filename] || ext_path || path)[1..-1]
  end

  raise Discourse::InvalidAccess if !extension || !extension.match?(IM_DECODERS)
  "#{extension}:#{path}"
end

.resize(from, to, width, height, opts = {}) ⇒ Object 



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# File 'app/models/optimized_image.rb', line 296

def self.resize(from, to, width, height, opts = {})
  optimize("resize", from, to, "#{width}x#{height}", opts)
end

.resize_instructions(from, to, dimensions, opts = {}) ⇒ Object 



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# File 'app/models/optimized_image.rb', line 203

def self.resize_instructions(from, to, dimensions, opts = {})
  ensure_safe_paths!(from, to)

  # note FROM my not be named correctly
  from = prepend_decoder!(from, to, opts)
  to = prepend_decoder!(to, to, opts)

  instructions = ["convert", "#{from}[0]"]

  instructions << "-colors" << opts[:colors].to_s if opts[:colors]

  instructions << "-quality" << opts[:quality].to_s if opts[:quality]

  # NOTE: ORDER is important!
  instructions.concat(
    %W[
      -auto-orient
      -gravity
      center
      -background
      transparent
      -#{thumbnail_or_resize}
      #{dimensions}^
      -extent
      #{dimensions}
      -interpolate
      catrom
      -unsharp
      2x0.5+0.7+0
      -interlace
      none
      -profile
      #{File.join(Rails.root, "vendor", "data", "RT_sRGB.icm")}
      #{to}
    ],
  )
end

.safe_path?(path) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'app/models/optimized_image.rb', line 166

def self.safe_path?(path)
  # this matches instructions which call #to_s
  path = path.to_s
  return false if path != File.expand_path(path)
  return false if path !~ %r{\A[\w\-\./]+\z}m
  true
end

.thumbnail_or_resize ⇒ Object 



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# File 'app/models/optimized_image.rb', line 199

def self.thumbnail_or_resize
  SiteSetting.strip_image_metadata ? "thumbnail" : "resize"
end

Instance Method Details

#calculate_filesize ⇒ Object 



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# File 'app/models/optimized_image.rb', line 144

def calculate_filesize
  path =
    if local?
      Discourse.store.path_for(self)
    else
      Discourse.store.download!(self).path
    end
  File.size(path)
end

#destroy ⇒ Object 



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# File 'app/models/optimized_image.rb', line 133

def destroy
  OptimizedImage.transaction do
    Discourse.store.remove_optimized_image(self) if self.upload
    super
  end
end

#filesize ⇒ Object 



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# File 'app/models/optimized_image.rb', line 154

def filesize
  if size = read_attribute(:filesize)
    size
  else
    size = calculate_filesize

    write_attribute(:filesize, size)
    update_columns(filesize: size) if !new_record?
    size
  end
end

#local? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'app/models/optimized_image.rb', line 140

def local?
  !(url =~ %r{\A(https?:)?//})
end