Unsuccessful Image Science

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Heh. I really meant to replace the legacy site with the updated Sinatra / CouchDB site (currently in beta). But then I had one last look at the homepage. It was slow:



Instead of taking 1-2 seconds to download each meal photo as it does on the beta site, it takes ~100ms on the legacy site:



Image thumbnails.

To get thumbnails in my application stack, I think I'll try a little Rack trickery. First, though I need ImageScience:

jaynestown% sudo apt-get install libfreeimage3 libfreeimage-dev 
sudo gem install image_science

I try to write Rack middle ware that will translate a thumbnail request into a normal request, then use image science to resize the image. I try, but am ultimately unsuccessful. This is where I am forced to leave off for the night:

class ThumbNail
  def initialize(app); @app = app end
  def call(env)

    if env['REQUEST_URI'] =~ /_sm.jpe?g/
      env['REQUEST_URI'].sub!(/_sm\./, '.')
      env['REQUEST_PATH'].sub!(/_sm\./, '.')
      env['PATH_INFO'].sub!(/_sm\./, '.')
      http_code, headers, original_body = @app.call(env)

      ImageScience.with_image_from_memory(original_body) do |img|
        img.resize(100, 150) do |small|
          small.save "/tmp/small.jpg"
        end
      end

      f = File.open  "/tmp/small.jpg"
      [http_code, headers, f.read]
    else
      @app.call(env)
    end
  end
end

use ThumbNail

I am getting this error in the Thin logs:

jaynestown% thin -R config.ru start
>> Thin web server (v1.2.2 codename I Find Your Lack of Sauce Disturbing)
>> Maximum connections set to 1024
>> Listening on 0.0.0.0:3000, CTRL+C to stop
!! Unexpected error while processing request: wrong argument type Rack::CommonLogger (expected String)

I will pick up tomorrow to continue working with ImageScience. If I am not able to make any more headway, I will drop down to RMagick.

Update: Ah, the original_body is not a string—it is something that responds to :each.