Manipulator

S3 is great for storing image files, but manipulating images after they’ve been saved to S3 (rotating, resizing, cropping, etc.) is a bit of a chore. Usually it goes something like this:

download file from S3, save to local tmp file
run graphics or image magick over local tmp file
push modified image back to S3
remember to clean up tmp file

After re-implementing this pattern a few times over (and filling up /tmp by forgetting the last step), we decided to roll this into a gem that makes S3 image manipulation as easy as:

m = Manipulator.new(:processor => :gm) # use GraphicsMagick; defaults to ImageMagick
m.manipulate({:bucket => 'my-bucket', :key => 'some/file.jpg'}) do |img|
  img.rotate(90)
  img.resize_to_fit(75,75)
end

The idea is to instantiate a Manipulator and then pass it a bucket name and key to manipulate. Manipulator will download your image to a local tmp file, then yield a MiniMagick::Image wrapping that file. Call methods on the yielded image to make modifications; as soon as the block returns, the modified image is pushed back to S3 and the tmp file is removed.

We’re using MiniMagick now instead of RMagick to save memory - we found that RMagick was a hog. MiniMagick is a lot more straightforward and has a nice interface for both GraphicsMagick (recommended) and ImageMagick.

Want to do something that MiniMagick doesn’t directly support, like removing all profiles from an image with GraphicsMagick (aka ImageMagick’s strip method)?

m.manipulate('my-bucket', 'my-key' do |img|
  `gm mogrify +profile '*' #{manipulator.temp_file_path}`
end

Install

$ gem install manipulator

Manipulator

Install

Dependencies

Future

Copyright