Rails - How to send an image from a controller

问题

in my rails app, I need to pass back a image.

I have a 1x1.gif tracking pixel in my route as follows:

 match "/_ctrack.gif" => "email_tracking_pixels#my_method"

In the controller:

def my_method
    send_data open('https://www.xxxxxx.com/images/1x1_transparent.gif') {|f| f.read }, :filename => '1x1_transparent.gif', :type => 'image/gif'
end

The problem is that for some reason sometimes this times outs. with the following error:

2011-03-07T20:08:36-08:00 heroku[router]: Error H12 (Request timeout) -> GET www.xxxxxxx.com/images/1x1_transparent.gif dyno=web.1 queue=0 wait=0ms service=0ms bytes=0
2011-03-07T20:08:36-08:00 app[web.1]: 
2011-03-07T20:08:36-08:00 app[web.1]: OpenURI::HTTPError (503 Service Unavailable):
2011-03-07T20:08:36-08:00 app[web.1]:   app/controllers/email_tracking_pixels_controller.rb:19:in `my_method'
2011-03-07T20:08:36-08:00 app[web.1]:   lib/rack/www.rb:7:in `call'

Any ideas on how I can pass this image that's stored locally, versus having to use open and make a web call back to my own server?

Thanks

回答1:

Is there a reason that you cannot save the file to public/_ctrack.gif, remove the route, and let the underlying web server serve the image?

If you need to process the image from disk, just use open on the local filename:

send_data open("#{Rails.root}/path/to/file.gif", "rb") { |f| f.read } .......

The rb sets the file to open and binary modes.

回答2:

Wouldn't be better to use send_file instead?

send_file Rails.root.join("public", "file.gif"), type: "image/gif", disposition: "inline"

来源：https://stackoverflow.com/questions/5228238/rails-how-to-send-an-image-from-a-controller