Programming in Ruby On Rails

This is a powerful feature of rails to communicate between two models in two different application running in two different server. ActiveResource:Base is the main class for mapping RESTful resources as models in a Rails application. Active Resource objects represent your RESTful resources as manipulatable Ruby objects. To map resources to Ruby objects, Active Resource  only needs a class name that corresponds to the resource name (e.g., the class User maps to the resources Products, very similarly to Active Record) and a site value, which holds the URI of the resources. class User < ActiveResource::Base   self.site = "http://api.products.com:3000/" end In order to access products.com controller you need to send the json response like i am going to call the index action so we need to write :- def index @products = Product.all respond_to do |format| format.json { render :json => @products} end end Now the User class is mapped to RESTful resources located

Sending emails in a rails application is very easy and quite handy using action mailer. First we will go through the basic setup of action mailer then we will go in details how it works. Step 1   We can setup a mailer class using rails generator   rails generate mailer UserMailer Step 2   Then we can create any instance method inside it.     def welcome_email(user)       @user = user       @url  = 'http://example.com/login'       mail(to: @user.email, subject: 'Welcome')     end Step 3   We can call this method form model or controller or any kind of callbacks using    Like     UserMailer.welcome_email(@user).deliver Step 4   You can set up a view template for the welcome_email in side the views/mailer directory   Like   welcome_email.html.erb   and you can specify the layout format here and can also access the instance variables defined in the       welcome_email(user) method Step 5   Additionally we can set up the smtp configuration inside

1) tail cannot watch no space left on device.    Solutions   a)  echo 900000 | sudo tee /proc/sys/fs/inotify/max_user_watches      Or Place   b) "fs.inotify.max_user_watches=16384" in /etc/sysctl.conf 2)  How to remove all files and sub-directories in a directory WITHOUT deleting the directory in bash? Solutions rm -rfv dontDeleteMe/*

If you want to upload bulk file in rails application just follow the following steps 1) create a rails application     rails new bulk_upload 2) Add passenger in your gem file     gem 'passenger' Now try to start with your rails application with the command   passenger start by default it will run on port number 3000 Now if you try to upload bulk files lets just say more than 500 mb or 800 mb you will get an error in the time of uploading like [ error] 4840#0: *557 client intended to send too large body: 94672000 bytes, client: 127.0.0.1, server: _, request: "POST /XXX HTTP/1.1", host: "localhost:3000" so this not error of you application this is the error thrown by passenger and ngnix which is responsible to run passenger First uninstall using purge to remove even configuration files and records:   apt-get purge nginx nginx-common nginx-full Then reinstall it  apt-get install nginx If above doesn't work for you you can also

To upgrade your rails version to rails 4 is pretty easy just follow the below steps. - I assume you have already rails installed in your system and also you are using rvm and ruby. - If you are not using rvm i recomend you to use rvm. please check the link for rvm ( http://rvm.io/ ) open a terminal and follow the steps. Step 1:  rvm get head (to get the latest version of rvm) Step 2:  rvm install 2.0.0 (to install ruby) Step 3:  rvm use 2.0.0 Step 4:  rvm gemset create rails4 Step 5:  gem install rails That's it to upgrade your rails version to rails 4 and ruby 2 in ubantu 12.04. Now if you run rails new new_app it will automatically create your rails application in rails 4 simple :) Further if you want to use both rails 3 and and rails 4 you can create a .rvmrc file in your application and mention the gem set in that file. echo "rvm ruby-1.8.7-p352@gemset" > .rvmrc And inside the file mentioned your gem set. like rvm use 2.0.0 rvm gem

Now its very easy to integrate solar search using sunspot_rails gem in rails 3 for fast searching.  Please follow the below steps to use solar search. 1) first install the gem    gem 'sunspot_rails'    gem 'sunspot_solr'   # optional pre-packaged Solr distribution for use in development 2) Run the bundle command to install the gems. 3) Run      rails generate sunspot_rails:install      to create the configuration file for the solar search. 4) Now you need to start the solar server     bundle exec rake sunspot:solr:start 5) If you have some exiting data in the data base please execute the command     rake sunspot:reindex 6) Now we are done with our setup.we need to configure our model so that search will work.    let say we have one event model in our application like    class Event < ActiveRecord::Base       attr_accessible  :content, :title     end Now if we want a full text search on the Event model. We just need to add one block in t

mongo.js:L112 Error: couldn't connect to server 127.0.0.1:27017 at src/mongo/shell/mongo.js:L112 Stop mongodb service sudo service mongodb stop Remove mongodb lock file sudo rm /var/lib/mongodb/mongod.lock Change ownership from root to mongodb path sudo chown -R mongodb:mongodb /var/lib/mongodb/ Start mongodb service sudo service mongodb start Test mongo app mongo Then you will be able to execute successfully (i hope).