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Class: ActiveStorage::Previewer::MuPDFPreviewer

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::ActiveStorage::Previewer
Instance Chain:
self, ::ActiveStorage::Previewer
Inherits: ActiveStorage::Previewer
Defined in: activestorage/lib/active_storage/previewer/mupdf_previewer.rb

Class Attribute Summary

Class Method Summary

::ActiveStorage::Previewer - Inherited

.accept?

Implement this method in a concrete subclass.
.new

Instance Attribute Summary

::ActiveStorage::Previewer - Inherited

#blob

Instance Method Summary

::ActiveStorage::Previewer - Inherited

#preview

Override this method in a concrete subclass.
#capture,
#download_blob_to_tempfile

Downloads the blob to a tempfile on disk.
#draw

Executes a system command, capturing its binary output in a tempfile.
#instrument, #logger, #open_tempfile, #service_name, #tmpdir

Constructor Details

This class inherits a constructor from ActiveStorage::Previewer

Class Attribute Details

.mutool_exists? ⇒ Boolean (readonly)

[ GitHub ] 

  


# File 'activestorage/lib/active_storage/previewer/mupdf_previewer.rb', line 18



def mutool_exists?
  return @mutool_exists unless @mutool_exists.nil?

  system mutool_path, out: File::NULL, err: File::NULL

  @mutool_exists = $?.exitstatus == 1
end


  







Class Method Details



  

    .accept?(blob)  ⇒ Boolean 
  



  

    
  





  


  [ GitHub ]


  

  


# File 'activestorage/lib/active_storage/previewer/mupdf_previewer.rb', line 6



def accept?(blob)
  pdf?(blob.content_type) && mutool_exists?
end


  








  

    .mutool_path  
  

  [ GitHub ]


  

  


# File 'activestorage/lib/active_storage/previewer/mupdf_previewer.rb', line 14



def mutool_path
  ActiveStorage.paths[:mutool] || "mutool"
end


  








  

    .pdf?(content_type)  ⇒ Boolean 
  



  

    
  





  


  [ GitHub ]


  

  


# File 'activestorage/lib/active_storage/previewer/mupdf_previewer.rb', line 10



def pdf?(content_type)
  Marcel::Magic.child? content_type, "application/pdf"
end


  







Instance Method Details



  

    #draw_first_page_from(file, &block)   (private)
  

  [ GitHub ]


  

  


# File 'activestorage/lib/active_storage/previewer/mupdf_previewer.rb', line 36



def draw_first_page_from(file, &block)
  draw self.class.mutool_path, "draw", "-F", "png", "-o", "-", file.path, "1", &block
end


  








  

    #preview(**options)  
  

  [ GitHub ]


  

  


# File 'activestorage/lib/active_storage/previewer/mupdf_previewer.rb', line 27



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