Rails action to send binary data

I have one old application where the attachment is store as an id in the filesystem. The customer wants to have the attachment with the right name. So I have made this small action which accepts the id of the requested object and send the file data.

  def send_bios
    redirect_to :action => 'bios' if params[:id].blank?
    @artist = Artist.find(params[:id]);
    contents = File.open(@artist.bios_path,"rb") {|io| io.read}
    send_data contents, :filename => "#{@artist.name}.pdf", :type => "application/pdf", :disposition => 'attachment'
  end

Here is how to make random images generation for your website.

First you must put your images in a folder /public/images/random_images or what ever.

Second you put images there and mark the filenames with a prefix, which image to which section will be visible on.

index_bottom_1.jpg -> for the index page on the bottom :)

index_bottom_2.jpg -> for the index page on the bottom

featured_art_1.jpg -> some panel.

featured_art_2.jpg -> some panel.

and so on…

Paste this method in your base controller. This method will be called to make list for a specific image folder and “filter” the images that are supposed to be showed in the different regions in @variables.

  before_filter :init_random_images
  protected # :) be carefull for this if you copy paste
  def init_random_images
    # collect some static images
    web_root = "images/imagestorage/random_images"

    all_images = Dir["#{RAILS_ROOT}/public/#{web_root}/*.jpg"]

    @random_head_images = []
    @random_indexbtm = []
    @random_featured = []
    @random_sales = []
    @random_services = []
    @random_framing = []
    @random_artistcollection = []
    all_images.each do |f|
      if File.stat(f).file?
        @random_head_images << ("/#{web_root}/" + File.basename(f)) if f =~ /head_images_/
        @random_indexbtm << ("/#{web_root}/" + File.basename(f)) if f =~ /indexbtm_/
        @random_featured << ("/#{web_root}/" + File.basename(f)) if f =~ /featured_/
        @random_sales << ("/#{web_root}/" + File.basename(f)) if f =~ /sales_/
        @random_services << ("/#{web_root}/" + File.basename(f)) if f =~ /services_/
        @random_framing << ("/#{web_root}/" + File.basename(f)) if f =~ /framing_/
        @random_artistcollection << ("/#{web_root}/" + File.basename(f)) if f =~ /artistcollection_/
      end
    end

Then paste this as a helper or in the base controller, to use it in your views. The method will give you from the images array, count number of images.

  helper_method :get_random_image
  def get_random_image(images, count)
    requested_images = []
    images_copy = images.clone
    [images_copy.size, count].min.times do
      index = rand(images_copy.size)
      requested_images << images_copy[index]
      images_copy.delete_at(index)
    end
    requested_images.flatten.compact
  end

here is an example how to use it.

<div id="static_logo" style="background:url(<%= get_random_image(@random_sales, 1) %>) no-repeat scroll left top;">
 

Future optimization

Put some caching, not to make

Dir["#{RAILS_ROOT}/public/#{web_root}/*.jpg"]
 

on every request.

10x Bl8cki to the nice code optimizations :)

I got this error when I have to upgrade one old project from rails 1.2.5 to rails 2.1 (the problem is not in rails)

ActionController::MethodNotAllowed

Only get, head, post, put, and delete requests are allowed.

The exception:

ActionController::MethodNotAllowed (Only get, head, post, put, and delete requests are allowed.):
    /usr/lib/ruby/gems/1.8/gems/actionpack-2.1.0/lib/action_controller/routing/recognition_optimisation.rb:65:in `recognize_path'
    /usr/lib/ruby/gems/1.8/gems/actionpack-2.1.0/lib/action_controller/routing/route_set.rb:384:in `recognize'

I got this error only when I access URL’s with param like

http://127.0.0.1:3000/dod/images/show_big_image/1639

I found that the problem was in the :id because without the :id the method was called correctly

This means that there is something with the routes.

Not working routes.rb: ….

  map.connect '', :controller => 'auth'

  # Install the default route as the lowest priority.
  map.connect ':controller/:action/:id'
  map.connect ':controller/:action/:sort_key/:sort_order'

it will work if you swap the last two lines….

  map.connect '', :controller => 'auth'

  # Install the default route as the lowest priority.
  map.connect ':controller/:action/:sort_key/:sort_order'
  map.connect ':controller/:action/:id'

It seems that it does reading the comments in the routes.rb is usefull. There is written:

# Install the default route as the lowest priority.

This error also occurs if you haven't restart your webserver. I know that there is no need to restart it but its true, try restarting and check.