railsで画像を扱う

urlからs3に画像をアップする

該当のファイルのcontent typeを知る

res = Net::HTTP.start(uri.host, uri.port) do |http|
  http.get(uri.path, {'User-Agent' => UrlConcern::USER_AGENT})
end
res.content_type

高さと幅を知る

res = Net::HTTP.start(uri.host, uri.port) do |http|
  http.get(uri.path, {'User-Agent' => UrlConcern::USER_AGENT})
end
magick = Magick::Image.from_blob(res.body).shift
width = magick.columns
height = magick.rows

• http://stackoverflow.com/questions/9997541/how-to-validate-image-width-and-height-on-upload-with-carrierwave-mini-magick-a

s3にアップする

option = {
  'Content-Type' => res.content_type,
  'Content-Length' => res.body.length,
  'x-amz-acl' => 'public-read',
  'Cache-Control' => "max-age=#{24*60*60*7}, private, must-revalidate",
}

s3_storage.put_object(s3_bucket, path, body, option)