Rails 3 send_data issue; difference between production and development - ruby-on-rails-3

Question

I have a strange bug in my Rails 3 app. I am using this code to send images that are not public:
image = open(f, "rb") { |io| io.read }
send_data(image, :disposition => 'inline')
I am using this code to display images in admin pages and user pages. If I use development environment this code works OK and the images are displayed on both pages. But if I use production environment, this images are displayed only in admin pages but not user pages. I can click on the images that are not displayed, and select "properties". Under image type I see:
application/xhtml+xml
But other public images has under the type JPG image/PNG image or something like this.
Which difference between the environemnts could be causing images not to work and how can I fix this, so the images will be properlly displayed on the all pages?

Answer 1

I had a distinctly similar symptom. I know this is an old issue and already resolved but I thought I would contribute the findings of my situation which turned out to be a different cause.
I was building a CSV file and using send_file to send the file to the browser. In development it worked great, in production the browser reported a page not found.
Here is the action from the controller.
def export
#campaign = LiveEmailCampaign.find params[:id]
#campaign.recipients_csv do |csv_file|
send_file csv_file,
filename: #campaign.name,
type: Mime::CSV
end
end
And the CSV is build from this code in a model.
def recipients_csv
tempfile = Tempfile.new(self.name.downcase.dasherize)
CSV.open tempfile, 'w' do |csv|
recipients.each do |recipient|
csv << [recipient]
end
end
yield tempfile
end
After a few minutes of research I determined that the culprit was a conflict between the XSendFile directive in Apache on the production server and the temporary path being used to write the CSV data to. In my case XSendFile was set for only the app root and the temp file was in /tmp on the server.
Instead of tampering with the XSendFile config at the server level I just instructed Tempfile to use the tmp folder in the Rails app.
So, I changed the call to Tempfile in the model method to this
tempfile = Tempfile.new(self.name.downcase.dasherize)
Now, Rails and Apache are friends again. I just need to refactor this code because it doesn't explicitly unlink the created temporary file. Best practice is to explicitly unlink temporary files.