Class: Dewey::Mime

Inherits:
Object
  • Object
show all
Defined in:
lib/dewey/mime.rb

Class Method Summary collapse

Class Method Details

.extension(file) ⇒ Object

Determine file extension by parsing the filename. When the filename has no extension, then instead examine the file’s mime type and intuit the extension.



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# File 'lib/dewey/mime.rb', line 38

def self.extension(file)
  extension = File.extname(file.path).sub('.', '')
  if extension.nil? || extension == ''
    mime_type = (`file --mime-type #{file.path}`).split(':').last.strip
    extension = mime_type_to_extension_mapping[mime_type]
  end
  extension.to_s.downcase
end

.guess_service(mime_type) ⇒ Object 



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# File 'lib/dewey/mime.rb', line 104

def self.guess_service(mime_type)
  services = { :document     => DOCUMENT_MIMETYPES,
               :drawing      => DRAWING_MIMETYPES,
               :presentation => PRESENTATION_MIMETYPES,
               :spreadsheet  => SPREADSHEET_MIMETYPES }

  services.each_key do |service|
    return service if services[service].values.flatten.include?(mime_type)
  end

  nil
end

.mime_type(file) ⇒ Object

Attempts to provide a mime_type that Google Docs finds acceptable. Certain types, when gathered from file require extra coercion and will be handled automatically.



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# File 'lib/dewey/mime.rb', line 50

def self.mime_type(file)
  type = case extension(file)
  when /csv/  then SPREADSHEET_MIMETYPES[:csv]
  when /doc$/ then DOCUMENT_MIMETYPES[:doc]
  when /docx/ then DOCUMENT_MIMETYPES[:docx]
  when /jpeg/ then DRAWING_MIMETYPES[:jpeg]
  when /htm/  then DOCUMENT_MIMETYPES[:html]
  when /ods/  then SPREADSHEET_MIMETYPES[:ods]
  when /odt/  then DOCUMENT_MIMETYPES[:odt]
  when /pdf/  then DOCUMENT_MIMETYPES[:pdf]
  when /png/  then DRAWING_MIMETYPES[:png]
  when /pps/  then PRESENTATION_MIMETYPES[:pps]
  when /ppt/  then PRESENTATION_MIMETYPES[:ppt]
  when /rtf/  then DOCUMENT_MIMETYPES[:rtf]
  when /svg/  then DRAWING_MIMETYPES[:svg]
  when /sxw/  then DOCUMENT_MIMETYPES[:sxw]
  when /tab/  then SPREADSHEET_MIMETYPES[:tab]
  when /tsv/  then SPREADSHEET_MIMETYPES[:tsv]
  when /txt/  then DOCUMENT_MIMETYPES[:txt]
  when /xls$/ then SPREADSHEET_MIMETYPES[:xls]
  when /xlsx/ then SPREADSHEET_MIMETYPES[:xlsx]
  end
  type.is_a?(Array) ? type.first : type
end

.mime_type_to_extension_mapping ⇒ Object

Merges then inverts all the mime type constants to make a new hash with mime types as keys and the corresponding file extensions as values. For example this:

:doc  => ['application/msword', 'application/vnd.ms-office'],

Becomes:

'application/msword' => :doc, 
'application/vnd.ms-office' => :doc

This is useful for intuiting file extensions based on mime types, which is handy when the filename doesn’t have an extension (e.g. when doing post-processing with paperclip).



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# File 'lib/dewey/mime.rb', line 88

def self.mime_type_to_extension_mapping
  doc_types = [DOCUMENT_MIMETYPES, DRAWING_MIMETYPES, PRESENTATION_MIMETYPES, SPREADSHEET_MIMETYPES]
  extensions = {}
  mime_types = {}
  doc_types.each { |doc_type| extensions.merge!(doc_type) }

  extensions.each do |extension, mime|
    if mime.is_a?(Array)
      mime.each { |m| mime_types[m] = extension }
    else
      mime_types[mime] = extension
    end
  end
  mime_types
end