/
mupdf_previewer.rb
40 lines (32 loc) · 1013 Bytes
/
mupdf_previewer.rb
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# frozen_string_literal: true
module ActiveStorage
class Previewer::MuPDFPreviewer < Previewer
class << self
def accept?(blob)
pdf?(blob.content_type) && mutool_exists?
end
def pdf?(content_type)
Marcel::Magic.child? content_type, "application/pdf"
end
def mutool_path
ActiveStorage.paths[:mutool] || "mutool"
end
def mutool_exists?
return @mutool_exists unless @mutool_exists.nil?
system mutool_path, out: File::NULL, err: File::NULL
@mutool_exists = $?.exitstatus == 1
end
end
def preview(**options)
download_blob_to_tempfile do |input|
draw_first_page_from input do |output|
yield io: output, filename: "#{blob.filename.base}.png", content_type: "image/png", **options
end
end
end
private
def draw_first_page_from(file, &block)
draw self.class.mutool_path, "draw", "-F", "png", "-o", "-", file.path, "1", &block
end
end
end