Read metadata with multi_exiftool and write it to a csv file

exif2csv.rb

require 'csv'
require 'multi_exiftool'

tags = ["filename", "filesize", "make", "model", "orientation", "modifydate", "exposuretime", "fnumber", "exposureprogram", "iso", "createdate", "flash", "focallength", "quality", "canonflashmode", "continuousdrive", "focusmode", "lenstype", "cameratemperature", "cameratype", "canonimagetype", "canonfirmwareversion", "ownername", "cameraorientation", "focusdistanceupper", "focusdistancelower"]

# reading the data
reader = MultiExiftool::Reader.new
reader.tags = tags
reader.filenames = Dir['*.jpg']
results = reader.read

# writing to csv
CSV.open('output.csv', 'w') do |csv|
  # write the header
  csv << tags
  # iterate over the results (res is a MultiExiftool::Values instance of one file)
  results.each do |res|
    # iterate over the tags and generate a new array of the values in res for each tag
    values = tags.map {|tag| res[tag]}
    # append it to the output
    csv << values
  end
end