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如何在 S3 存储中旋转图像，我正在使用 Attachment_fu 和 Amazon S3 ，我想实现一个功能，让用户通过旋转 90 度来编辑现有图像。我想知道是否有人玩过这个，或者有任何想法。我目前正在使用 rmagick 来旋转 Rails 目录中的图像。但在 AWS S3 存储中无法旋转图像。

require 'RMagick'

def rotate
    photo   = Photo.find(params[:id])
    image   = Magick::ImageList.new(photo.file)
    image   = image.rotate(90)
    image.write(photo.file)
end

我正在使用这个宝石：

gem 'pothoven-attachment_fu'
gem 'aws-s3'
gem 'rmagick'
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1 回答 1

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我解决了这个问题。

def update_photo
      require 'RMagick'
      require 'base64'

      # get the image data in Photo table
      @photo = Photo.where(id: params[:photo_id]).first

      # get image path in S3 url and encode to Base64 binary
      img_url = @photo.s3_url()
      img_uri = URI.parse(img_url)
      base64_image = Base64.encode64(open(img_uri) { |io| io.read })
      image_file_name = File.basename(img_uri.path,File.extname(img_uri.path))
      filename_path = "#{Rails.root.to_s}/tmp/#{image_file_name}"

      # create tempfile in rails root/tmp folder and decode the Base64 binary into image file, then processing RMagick to rotate the image into desire image rotation.
      @tempfile = Tempfile.new(filename_path)
      @tempfile.binmode
      @tempfile.write Base64.decode64(base64_image)
      @tempfile.close

      # rotate image using RMagick
      Magick::Image.read(img_uri).first.rotate!(params[:photo_degree].to_i).write(@tempfile.path)

      # for security we want the actual content type, not just what was passed in
      # get mime type of image and passed into ActionDispatch type
      content_type = `file --mime -b #{@tempfile.path}`.split(";")[0]

      # we will also add the extension ourselves based on the above
      # if it's not gif/jpeg/png, it will fail the validation in the upload model
      extension = content_type.match(/gif|jpeg|png/).to_s
      extension = "jpg" if extension == "jpeg"

      # append filename to prevent browser image caching
      filename_path += "_#{params[:photo_degree]}"

      filename_path += ".#{extension}" if extension

      # passed the data into  Rails core ActionDispatch instead of file input object
      file = ActionDispatch::Http::UploadedFile.new({
        tempfile: @tempfile,
        type: content_type,
        filename: filename_path
      })

      # delete the existing image
      @photo.destroy 

      # create new image
      img_rotate                = Photo.new()
      img_rotate.id             = @photo.id
      img_rotate.uploaded_data  = file
      img_rotate.save

       ensure
          clean_tempfile

end

  def clean_tempfile
    if @tempfile
      @tempfile.close
      @tempfile.unlink
    end
  end
于 2015-08-18T06:41:13.040 回答