Integrating turbolinks in your Rails application

We are all excited in a new addition to rails plugins family that is turbolinks.

If you have tried to include it in your application, you may have noticed that turbolinks doesn’t trigger your $.ready, because there is no full page reload. As a consequence your javascripts that are bound to $.ready won’t trigger. I will only hack the finished event that is “page:change” which occurs when the page is refreshed. You have other events and their descriptions on the turbolinks github page. Here is a fast hack that i came with. Some of the code is taken from turbolinks library.

First have your $.ready trigger the “page:change” event. This is done, so we can bind everything that is now bound to document.ready to “page:change”

$.ready ->
  triggerEvent "page:change"

triggerEvent = (name) ->
  event = document.createEvent 'Events'
  event.initEvent name, true, true
  document.dispatchEvent event

Now when we have $.ready calling “page:change” we can use it in our application like this

document.addEventListener "page:change", ->
  alert "I am called from $.ready and page:change"

Will Paginate in Rails using remote request

Have you ever wondered why is there no remote option for will_paginate gem? It’s too complex and data dependent to handle all possible situations. I have made a workaround that can help you implement simple ajax pagination for your rails application. I will be replacing the whole yield part here, but you can customize it whatever way you like.

Step 1. Extract your required view into a partial so you have
index.html.erb

<!-- app/views/posts/index.html.erb -->
< %= render "index" %>

_index.html.erb

<!-- app/views/posts/_index.html.erb -->
<h1>Listing posts</h1>
<table id="posts">
  <tr>
    <th>Title</th>
    <th>Body</th>
    <th></th>
    <th></th>
    <th></th>
  </tr>
 < %= render partial: 'post', collection: @posts %>
</table>
< %= will_paginate @posts, remote: true %>
<br />
< %= link_to 'New Post', new_post_path, remote: true %>

Note the remote: true part of the will_paginate call, we will bind the javascript to it in an instance.

2. Add a div surrounding your yield tag in your layout

<!-- app/views/layouts/application.html.erb -->
<div id="content>
  < %= yield %>
</div>

3. Create index.js.erb which will replace the contents of the div with paged table data.

// app/views/posts/index.js.erb
$("div#content").html('< %= escape_javascript(render "index") %>');

4. Bind the will_paginate link click to the rails remote call using coffeescript in

# app/assets/javascripts/posts.js.coffee
$('.pagination[remote=true] a').live 'click', ->
  window.history.pushState(null, 'hi', $(this).attr("href"))
  $.rails.handleRemote($(this))
  return false

We also change the address in the navigation bar with PushState, because it can happen someone will press F5 or something and reload with a different params[:page].

Update: As my coworker Oliver mentioned, i forgot to include responding to js in our controller for the index action

def index
  @posts = Post.paginate(per_page: 8, page: params[:page]
  respond_to do |format|
    format.html
    format.js
  end
end

Installing Rails Server on Ubuntu 12.04 with RVM, Nginx, Passenger and Oracle support

We have a new product ready and it is a Ruby on Rails webshop bundled with an ERP software written on Oracle Forms 6i. I will not go into the details of this work, maybe later i will make some posts of the process but as it is very linked to current software(only authentication is done with Devise, every other data and processing is done internally on Oracle database) there is no sense for me to explain it deeper. Off to the installation.

Server installation and configuration

First we need a clean install of Ubuntu server 12.04, x86 or x64 version will work all the same, but be careful later on when you download the Oracle instant client. On the installation, fill all the relevant data needed, and for installed services, choose only the ssh server, as you won’t be needing anything more. Another reminder: this will only be the webserver, assuming that you have the Oracle database installed somewhere in network reach.

After you login to your server for the first time, take your time to set up the ip address because it defaults to dhcp.
Edit the /etc/network/interfaces file and fill your address, gateway and dns servers(this is a new thing, i think starting in 12.04 /etc/resolv.conf gets updated whenever you restart networking, so everything you write there will get overwritten)


# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
    address 192.168.0.100
    netmask 255.255.255.0
    gateway 192.168.0.1
    dns-nameservers 8.8.8.8 8.8.4.4.

After the config is saved, restart the networking and do a full update/upgrade of the server to get the latest packages installed:


sudo /etc/init.d/networking restart
sudo apt-get update
sudo apt-get -y dist-upgrade

After all is done, reboot your server.

Installing RVM and latest Ruby version

After your server is updated you can proceed with installing RVM and the latest stable Ruby(as i’m writing this, the latest version is 1.9.3p194 so i will be using this version)

First we install RVM prerequisites:

# rvm requires curl and git to install, and you will probably need them on your server so go ahead and install them
apt-get -y install git-core curl

# Installing RVM as sudo, to get RVM ruby system wide
curl -L get.rvm.io | sudo bash -s stable

# sourcing rvm environment so you can use it untill you login again
source /etc/profile.d/rvm.sh

And that will install RVM and make it available for all users that belong to the rvm group(hint: edit /etc/groups and add rvm after the desired username). After installing RVM and adding our user to the  rvm group we are off to installing latest Ruby version

# install all requirements needed for YARV/MRI Ruby (you can easily get these by running 'rvm requirements' in the terminal)
sudo apt-get install build-essential openssl libreadline6 libreadline6-dev curl git-core zlib1g zlib1g-dev libssl-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt-dev autoconf libc6-dev ncurses-dev automake libtool bison subversion

# install requirements needed for Oracle Instant client
sudo apt-get install libaio1

# install latest stable 1.9.3 and set it as default ruby version
rvmsudo rvm install 1.9.3 --default

# disable installation of RDoc and RI when installing gems
echo 'gem: --no-ri --no-rdoc'  >> ~/.gemrc

# install bundler gem, as you will later need for deployment
rvmsudo gem install bundler

 Installing Passenger and Nginx web server

After you have ruby and everything needed installer go and install passenger gem and nginx web server with it

# install  passenger gem
rvmsudo gem install passenger

# install passenger nginx module (and nginx if you haven't installed it yet), choose first option(Yes: download, compile and install Nginx for me) when it asks you what to do
# if there are more requirements the script will tell you and after you install them rerun the command
rvmsudo passenger-install-nginx-module

The installation will set up the nginx.conf file for you and show you how you can enable a rails site on your server. But i will include a sample config later on.
Just for convenience, symlink nginx conf folder that is in /opt/nginx/conf to /etc/nginx and download linode nginx startup/shutdown script

# symlink nginx conf folder to /etc/nginx
sudo ln -s /opt/nginx/conf /etc/nginx

# download linode nginx init script and create the service
wget -O init-deb.sh http://library.linode.com/assets/660-init-deb.sh
sudo mv init-deb.sh /etc/init.d/nginx
sudo chmod +x /etc/init.d/nginx
sudo /usr/sbin/update-rc.d -f nginx defaults

Installing Oracle instant client

To connect your Rails application to Oracle database, you will have to install Oracle client, either full or instant one. As installing full client requires alien and converting .rpm packages to .deb it’s a bit of a hassle. Also, it will consume more space on your drive, and all that is unnecessary, we are trying to keep it small here.

First you should download zip files from Oracle site depending what architecture you are running:
Oracle Instant Client 11.2 for linux:  X86X64

Download only instantclient-basic, instantclient-sqlplus and instantclient-sdk zip archives and unzip them all into the same instantclient_11_2 folder. Now as sudo move that folder so the path is /opt/oracle/instantclient_11_2

After that you only have to add two environment variables to be able to install ruby-oci8 gem, which is prerequisite for running Ruby applications on Oracle database. Add the following lines to /etc/enviroment file

LD_LIBRARY_PATH=/opt/oracle/instantclient_11_2

# as i am from Croatia, and we use our national date and money preferences, my NLS_LANG is this one, yours will maybe be different
NLS_LANG=CROATIAN_CROATIA.AL32UTF8

After you reboot you have to symlink the oracle library so it will function properly(i don’t know why they don’t do this themselves).

ln -s /opt/oracle/instantclient_11_2/libclntsh.so.11.1 /opt/oracle/instantclient_11_2/libclntsh.so

After that try and install ruby-oci8 gem.

rvmsudo gem install ruby-oci8

If there are no errors, and there should not be if you followed the guide, you are set to deploy your application on the server you just installed. In the next post, i plan to write something about tips, tricks and caveats of developing Rails applications on Oracle database.

Useful links to get and learn about all the stuff i have mentioned in the post:

Ruby Version Manager(RVM): https://rvm.io
Ruby: http://ruby-lang.org
Oracle Instant Client 11.2 for linux:  X86, X64
Passenger server: http://www.modrails.com/

Speaking at a conference with no time to prepare

I was surprised to know that i am presenting a product this week at the oracle user conference HROUG.hr

A colleague and me were supposed to hold a talk about creating our latest web app, a nursery management app created using Ruby on Rails and Oracle XE. As we thought, the talk was canceled and we were free of all obligation. But no, this saturday, 5 days before the talk, i was reviewing the agenda and found out the talk is on. So what can i do?

I will walk you through the steps, though they shouldn’t be used unless you are in a crunch, and it is not longer than an hour, luckily my talk is only half an hour.

1. Gather as much irrelevant info about the company and the client(our somewhat of a manager sorted that out)

2. If you are the developer, try to talk as much as you can about the technology and its integration( I love Rails so that is no problem )

3. Scrape out the basic workflow of the application you are presenting, user experience and why is something done in that way.

4. Take as much screenshots as it takes

5. Talk about details in the application, and finally leave at least 5 minutes for the audience to ask questions.

I managed to cramp all that into 30 minutes, i will update this post after i’m done thursday morning, to write how the talk went.

Lesson for everyone: Know your talking schedule at least one month before you are doing a talk, this way you can prepare and practice.

Update: The talk went surprisingly well, the hall was almost full, with 24 people listening. I haven’t got my reviews yet, but i feel they will be great for my first conference talk.

Rails 3.1 beta on Ubuntu

As i have written before, i use Ubuntu for my rails development, and have been using it as my main OS last 10 months. I have been trying all the rails 3.1 beta hype and encountered a problem running 3.1 apps on my machine.

The main problem is with CoffeScript and its compiling into “real” JavaScript. So here is an easy way to enable your machine for rails 3.1. You have to install Node.js on your machine( i have tried all other Javascript runtimes with no luck). All the instructions for other platforms are listed on the project’s GitHub page, i will include only the ubuntu procedure here.


sudo apt-get install python-software-properties

sudo add-apt-repository ppa:jerome-etienne/neoip

sudo apt-get update

sudo apt-get install nodejs

And that is all, hope i have made your life easier at least a bit.