Capture requests for image in assets - ruby-on-rails

Question

I want to store an image in my Rails app, hand out the direct URL for it and capture the requests for it.
I have a created a controller/action images_controller#show, a layout file with only yield and a view file with one single image_tag.
The rendered direct link to the image: https://example.com/assets/a-3883fc3a19a59c2cac8e30c827e81ec6f67538dd0213393d08a425bc800a06a3.jpg
How would I capture requests for this image as they don't pass the controller? My server logs only shows
Started GET "/assets/a-3883fc3a19a59c2cac8e30c827e81ec6f67538dd0213393d08a425bc800a06a3.jpg"

Answer 1

Since the "static" assets are placed in the web root of the web server they are served without Rails intervening in production.
In development config.serve_static_assets = true is used to get rails to serve assets so that the are compiled on demand. However that would be prohibitively slow in production.
There are two basic alternatives here and which to use depends on your use case:
1. Do it on the web server:
This is mostly applicable if uploading the images is a developer concern and you want metrics for technical or marketing reasons.
Both NGinx and Apache can generate metrics for the number of unique visits on a URI. Exactly how to do this depends on your web server / sass provider and the rest of infrastructure in place.
If you decide to go down this route I recommend you start a new question with the details of your setup.
https://www.digitalocean.com/community/tutorials/how-to-target-your-users-with-nginx-analytics-and-a-b-testing
https://devcenter.heroku.com/articles/shogun
2. Handle images as any other resource
If you intend have users upload images you and want tracking or any form of access control you would have the user upload images into a non public directory and serve them through a run of the mill rails controller.
Gems like paperclip or carrierwave can make this far easier.
# config/routes.rb
resources :images
# app/models/image.rb
class Image < ActiveRecord::Base
belongs_to :user
validates_presence_of :file
end
# app/controllers/images_controller.rb
class ImagesController < ApplicationController
def new
#image = Image.new
end
def create
#image = Image.new(image_params)
#image.save
respond_with(#image)
end
def index
#images = Image.all
end
def show
#images = Image.find(params[:id])
respond_to do |f|
format.html {}
format.jpg { send_file #image.file , type: 'image/jpeg', disposition: 'inline' }
end
end
# ...
end