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# frozen_string_literal: true
module ActiveStorage
class Previewer::PopplerPDFPreviewer < Previewer
class << self
def accept?(blob)
blob.content_type == "application/pdf" && pdftoppm_exists?
end
def pdftoppm_path
ActiveStorage.paths[:pdftoppm] || "pdftoppm"
end
def pdftoppm_exists?
return @pdftoppm_exists if defined?(@pdftoppm_exists)
@pdftoppm_exists = system(pdftoppm_path, "-v", out: File::NULL, err: File::NULL)
end
end
def preview
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"
end
end
end
private
def draw_first_page_from(file, &block)
# use 72 dpi to match thumbnail dimensions of the PDF
draw self.class.pdftoppm_path, "-singlefile", "-r", "72", "-png", file.path, &block
end
end
end
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