read exif metadata from uploaded pics on the browser

read_exif.rb

require 'sinatra'

set :port, 8080
set :bind, '0.0.0.0'

get "/" do
  erb :index
end

get '/get_exif' do
  "Upload an image."
end

post '/get_exif' do
  @filename = params[:file][:filename]
  file = params[:file][:tempfile]
  path = "./tmp/#{@filename}"

  File.open(path, 'wb') do |f|
    f.write(file.read)
  end

  @exif = `exiftool #{path}`
  `rm #{path}`
  erb :exif
end