/
poppler_pdf_previewer.rb
39 lines (32 loc) · 1.06 KB
/
poppler_pdf_previewer.rb
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
# frozen_string_literal: true
module ActiveStorage
class Previewer::PopplerPDFPreviewer < Previewer
class << self
def accept?(blob)
pdf?(blob.content_type) && pdftoppm_exists?
end
def pdf?(content_type)
Marcel::Magic.child? content_type, "application/pdf"
end
def pdftoppm_path
ActiveStorage.paths[:pdftoppm] || "pdftoppm"
end
def pdftoppm_exists?
return @pdftoppm_exists unless @pdftoppm_exists.nil?
@pdftoppm_exists = system(pdftoppm_path, "-v", out: File::NULL, err: File::NULL)
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)
# use 72 dpi to match thumbnail dimensions of the PDF
draw self.class.pdftoppm_path, "-singlefile", "-cropbox", "-r", "72", "-png", file.path, &block
end
end
end