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.

It is very easy to handle ajax pagination as described on this post here.

I want to give one full example.

Here is how my form looks:

<% form_remote_tag :url => {
                      :action => 'handle_urls',
                      :script_id => @script,
                      :page => params[:page],
                    },
  :html => {:id => 'f'},
  :update => "filtered_articles_pane" do %>

Here is how my will_paginate helper looks:

<%= will_paginate @filtered_urls,
  :renderer => 'RemoteLinkRenderer',
  :remote => { :with => "'script_id=#{@script.id}&approved_flag='+$(\'approved_flag\')",
  :update => 'filtered_articles_pane'} %>

I have used the improved version of the will_paginate:

# Use it like so…
# will_paginate :collection, :remote => {:with => 'value', :update => 'some_div'} 

class RemoteLinkRenderer < WillPaginate::LinkRenderer
  def initialize(collection, options, template)
    @remote = options.delete(:remote)
    super
  end

  def page_link_or_span(page, span_class = 'current', text = nil)
    text ||= page.to_s
    if page and page != current_page
      @template.link_to_remote(text, {:url => url_options(page), :method => :get}.merge(@remote))
    else
      @template.content_tag :span, text, :class => span_class
    end
  end
end

Update for will_paginate 2.3.x

# app/helpers/remote_link_renderer.rb

class RemoteLinkRenderer < WillPaginate::LinkRenderer
  def prepare(collection, options, template)
    @remote = options.delete(:remote) || {}
    super
  end

protected
  def page_link(page, text, attributes = {})
    @template.link_to_remote(text, {:url => url_for(page), :method => :get}.merge(@remote))
  end
end

The most valuable usage for scaffolding is when you use it in the administration part of the site. The administration is usually separated in separate module/folder.

The new rails scaffolding is not good because:

• It is time taking to setup nested scaffold
• I have tons of uselss source code in the scaffolding like respond_to ... that is usable very rare or never.
• The HTML that is generated is ugly and not usable for CSS skin
• Not using the nice ruby style iterations .each instead of for's
• Code repetition, the “new” and the “edit” views has the same form elements
• Not easy to find documentation

I find Akita article for scaffolding. It is is great that he has covered some real cases. It is a lot of reading and I must read/copy/paste every time I need to make a scaffold. Here is step by step on making scaffold for administration.

• ruby script/generate scaffold admin::BadArticle NOT PLURAL!
  • user:references
  • description:text,string
  • fixed:boolean
  • timestamps are automaticaly added
• Add in routes.rb

  • map.namespace :admin do |admin|
      admin.resources :bad_articles
    end

• Model
  • Rename admin::BadArticles -> BadArticle,
  • move it to the model directory
  • rename the file
• Fix the migration file:
  • remove the prefix from the migration class,
  • remove the prefix from table name
  • rename the file
• URL references
  • admin_bad_articles_url
  • redirect_to([:admin, bad_article])
• Controller
  • rename all Admin::BadArticles -> BadArticle except in the controller name
  • Probably you will want to make your scaffold inhired your base admin controller

  • def create
       ...
       format.html { redirect_to([:admin, @filtered_url]) }
       ...
    end

  • def update
        ...
            format.html { redirect_to([:admin, @filtered_url]) }
        ...
    end

  • class Admin::BadArticlesController < ApplicationController

    class Admin::BadArticlesController < Admin::AuthController
      layout 'admin'
     (in case that you don't have it in the base controller)

  • def index
      @admin_bad_articles = BadArticle.find(:all)
      respond_to do |format|
        format.html # index.html.erb
        format.xml  { render :xml => @admin_bad_articles }
      end
    end

• Index.rhtml.erb

  • <td><%= link_to 'Edit', edit_admin_bad_article_path(bad_articles) %></td>

  • <%= link_to 'New bad_articles', new_admin_bad_articles_path %>

• edit.rhtm

  • <%= link_to 'Show', @bad_article %> |
    <%= link_to 'Back',bad_articles_path %><%= link_to 'Show', [:admin, @bad_article_url] %> |
    <%= link_to 'Back', admin_bad_articles_path %>

• show.html.erb

  • <%= link_to 'Edit', edit_filtered_url_path(@filtered_url) %> |
    <%= link_to 'Back', filtered_urls_path %>

• new.rhtml

  • <% form_for(@bad_article) do |f| %><% form_for([:admin, @bad_article]) do |f| %>

  • <%= link_to 'Back', bad_articles_path %><%= link_to 'Back', admin_bad_articles_path %>

Traps:

The order of the routes in routes.rb does matter! In order to make the REST work you must have this block at the bottom of your routes.rb like this:

map.namespace :admin do |admin|
  admin.resources :bad_articles
end

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


Remove simply_helpful plugin if you get the error:

undefined method `new_record?' for #Array:0x532a3e8

Debuging tools:

rake routes

Tips:

How to add custom actions to the REST

map.namespace :admin do |admin|
  admin..esources :bad_articles, :member => {:toggle => :get}
  admin.resources :orders, :member => { :resend => :post }
  admin.resources :users,  :collection => { :filter => :any }
end

Then in the controller:

def toggle
  @bad_article = BadArticle.find(params[:id])
  @bad_article.fixed = ! @bad_article.fixed
  @bad_article.save
  redirect_to  admin_bad_articles_url
end

And in the view:

<%= toggle_admin_bad_article_url(filtered_url) %>

More reading here

Resources:

• restful_rails_en
• Akita article
• http://frozenplague.net/2008/01/06/restful-routing-an-overview/

auto_scope

source: http://blog.teksol.info/archives/2007/3

class Contact < ActiveRecord::Base
auto_scope \
:old => {:find => {:conditions => [“born_on < ?“, 30.years.ago]}},
:young => {:find => {:conditions => [“born_on > ?“, 1.year.ago]}}
end

class Testimonial < ActiveRecord::Base
auto_scope \
:approved => {
:find => {:conditions => [“approved_at < ?“, proc {Time.now}]},
:create => {:approved_at => proc {Time.now}}},
:unapproved => {
:find => {:conditions => “approved_at IS NULL“},
:create => {:approved_at => nil}}
end

Rails internals!?

http://localhost:3000/rails/info/properties

Threads

• nice post on custom thread handling
• spawn plugin
• the api