Accessing windows Files from Ubuntu

Go to Home Folder >> File System >> host >> Users

Rails 3 jquery_ujs - link_to :remote triggers two ajax calls on click

Issue:  link_to :remote triggers two ajax calls on click in rails 3+

Solution: Make sure you have not included //= require jquery_ujs in the application.js file in assets since jquery-rails already handles this in rails 3.1

courtesy: link

Rails 3 - Installing pg with native extensions

Installing pg (0.13.2) with native extensions
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

Solution:
sudo apt-get install libpq-dev

Invalid CSS issue on RAILS_ENV=production bundle exec rake --trace assets:precompile

1)Remove all the requires in app/assets/application.css file

2)Now add config.assets.precompile = ['*.css'] in application.rb file

3)Now run RAILS_ENV=production bundle exec rake --trace assets:precompile which will help to trace the exact files where the css issue exist and then fix all the issues mentioned in the css files

4) When all the css issues are fixed then remove config.assets.precompile = ['*.css'] and then revert any requires in your application.css which was present earlier and run the RAILS_ENV=production bundle exec rake --trace assets:precompile again. This should fix the issue.

Connecting datacard on Ubuntu 11

1) Go to -Dash home >> Network Connections
2) Select Mobile Broadband and click on "Add"
3) Select your mobile connection  in dropdown >> "Continue"
4) Select your country and click on "Continue"
4) Select your service provide and click on "Continue"
5) Select your plan and click on "Apply" >> "Save"

Using bundle exec in Rails 3

1)bundle exec executes a command in the context of your bundle.
That means it uses the gems specified in your Gemfile. Much of the time, running bundle exec rake foo has the same results as if you just ran rake foo, especially if you have the same gems installed systemwide as in your Gemfile. However, some applications may specify different versions of gems than the ones you have installed systemwide, and may want those exact gems and versions to be able to run correctly. If you just run without bundle exec, you may get some weird errors.
Using bundle exec guarantees that the program is run with the environment specified in the gemfile, which hopefully means it is the environment that the creators of the program want it to be run in, which hopefully means it should run correctly no matter what weird setup you have on your computer.
It basically standardizes the environment under which the program is run. This helps avoid version hell and makes life much easier.
See http://gembundler.com/man/bundle-exec.1.html for more info.

Installing Chrome on Ubuntu

Run the following commands in terminal:

1) wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add -

2) sudo sh -c 'echo "deb http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google.list'

3) sudo apt-get update

4) sudo apt-get install google-chrome-stable

Rails 3 Ubuntu 11.10 Installing nokogiri (1.5.2) with native extensions

Issue:
Using bundler (1.1.3)
Installing nokogiri (1.5.2) with native extensions
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

        /home/user/.rvm/rubies/ruby-1.9.2-p318/bin/ruby extconf.rb
checking for libxml/parser.h... yes
checking for libxslt/xslt.h... no
-----
libxslt is missing.  please visit http://nokogiri.org/tutorials/installing_nokogiri.html for help with installing dependencies.
-----
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
    --with-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/home/ganesh/.rvm/rubies/ruby-1.9.2-p318/bin/ruby
    --with-zlib-dir
    --without-zlib-dir
    --with-zlib-include
    --without-zlib-include=${zlib-dir}/include
    --with-zlib-lib
    --without-zlib-lib=${zlib-dir}/lib
    --with-iconv-dir
    --without-iconv-dir
    --with-iconv-include
    --without-iconv-include=${iconv-dir}/include
    --with-iconv-lib
    --without-iconv-lib=${iconv-dir}/lib
    --with-xml2-dir
    --without-xml2-dir
    --with-xml2-include
    --without-xml2-include=${xml2-dir}/include
    --with-xml2-lib
    --without-xml2-lib=${xml2-dir}/lib
    --with-xslt-dir
    --without-xslt-dir
    --with-xslt-include
    --without-xslt-include=${xslt-dir}/include
    --with-xslt-lib
    --without-xslt-lib=${xslt-dir}/lib

Fix:
Do the following:
1) sudo apt-get install libxml2-dev
2) sudo apt-get install libxslt1-dev
and then
bundle install

Update DelayedJob run_at to change daily emails send time

Below is just a sample code.
1) Create a table to track delayed jobs

class CreateTrackDelayedJobs < ActiveRecord::Migration
  def self.up
    create_table :track_delayed_jobs do |t|
      t.integer :delayed_job_id
      t.integer :user_id
      t.integer :item_id

      t.timestamps
    end
  end

  def self.down
    drop_table :track_delayed_jobs
  end
end




2)Sample code to send daily news letters

a) Add a rake task which can be run everyday

task :send_news_letters => :environment do
        items = Item.all
        items.each do |current_item|
          
            send_time = Time.zone.local(Date.today.year, Date.today.month, Date.today.day, hours, minutes)
            NewsLetter.send_at(send_time, :send_digest, curent_item.id)
        end

b)

class NewsLetter

 def self.send_in(time, method, *args)
        send_at time.from_now, method, *args
    end

    def self.send_at(time, method, *args)
        dj = Delayed::Job.enqueue Delayed::PerformableMethod.new(self, method.to_sym, args), 0, time
        track_dj = TrackDelayedJob.where("item_id = ?",args[0]).first
        if track_dj.nil?
            TrackDelayedJob.create(:delayed_job_id => dj.id, :item_id => args[0])
        else
            old_dj = Delayed::Job.find_by_id(track_dj.delayed_job_id)
            old_dj.destroy unless old_dj.nil?
            track_dj.update_attribute(:delayed_job_id, dj.id)
        end
    end

def self.send_digest(item_id)
#write your code to send digest.
end

end

c) When you want to update already set delayed job then

NewsLetter.update_delayed_job_time(item_id, time)

add this in NewsLetter class
def self.set_delayed_job_time(item_id, time)
   
        track_dj = TrackDelayedJob.where("item_id = ?", item_id).first
        dj = Delayed::Job.find_by_id(track_dj.delayed_job_id) unless track_dj.nil?
        unless dj.nil?
            #below code is required in case you want to convert hours and minutes
            #   time = "#{Date.today} #{hours}:#{minutes}".to_time           
            dj.run_at = time
            dj.save
        end
    end

end

Rails - Install and starting memcached on windows

1) Download Memcached for windows and extract it.

2) Open the command prompt as administrator and then run the command (assuming
your memcached is in c:\memcached)

c:\memcached\memcached.exe -d install

(Incase you get the below error:
C:\Windows\System32>c:\memcached\memcached.exe -d install
failed to install service or service already installed
Please make sure your are running the command prompt as administrator
start>command prompt> right click it and run as administrator.)

3) Start the server by:
C:\Windows\system32>net start "memcached Server"
The memcached Server service is starting.
The memcached Server service was started successfully.

Rails Resque + RuntimeError at /resque/overview ERR unknown command 'server' issue

Issue: RuntimeError at /resque/overview ERR unknown command 'server' on windows at localhost:3000/overview


Fix: Just do a 'gem cleanup resque' to remove older versions of resque and then 'bundle update'.

Rails 3 Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes.

Issue:
Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes.
/home/user/.rvm/gems/ruby-1.9.2-head/gems/execjs-1.2.6/lib/execjs/runtimes.rb:46:in `autodetect'
/home/user/.rvm/gems/ruby-1.9.2-head/gems/execjs-1.2.6/lib/execjs.rb:5:in `'
/home/user/.rvm/gems/ruby-1.9.2-head/gems/execjs-1.2.6/lib/execjs.rb:4:in `'
/home/user/.rvm/gems/ruby-1.9.2-head/gems/coffee-script-2.2.0/lib/coffee_script.rb:1:in `require'

Fix:

Add gem ‘therubyracer’ into Gemfile and then do a 'bundle install'

Running a specific migration file

1) Incase you want to run migration from a particular file then 

rails console>> require "db/migrate/20110210070832_create_companies.rb"
>> CreateCompanies.up

other ways:

rake db:migrate:up VERSION=my_version

rake db:migrate:down VERSION=my_version

Installing mysql2 gem on Ubuntu

Issue:
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

        /home/user/.rvm/rubies/ruby-1.9.2-head/bin/ruby extconf.rb
checking for rb_thread_blocking_region()... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lm... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lz... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lsocket... no
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lnsl... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lmygcc... no
checking for mysql_query() in -lmysqlclient... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
    --with-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/home/user/.rvm/rubies/ruby-1.9.2-head/bin/ruby
    --with-mysql-config
    --without-mysql-config
    --with-mysql-dir
    --without-mysql-dir
    --with-mysql-include
    --without-mysql-include=${mysql-dir}/include
    --with-mysql-lib
    --without-mysql-lib=${mysql-dir}/lib
    --with-mysqlclientlib
    --without-mysqlclientlib
    --with-mlib
    --without-mlib
    --with-mysqlclientlib
    --without-mysqlclientlib
    --with-zlib
    --without-zlib
    --with-mysqlclientlib
    --without-mysqlclientlib
    --with-socketlib
    --without-socketlib
    --with-mysqlclientlib
    --without-mysqlclientlib
    --with-nsllib
    --without-nsllib
    --with-mysqlclientlib
    --without-mysqlclientlib
    --with-mygcclib
    --without-mygcclib
    --with-mysqlclientlib
    --without-mysqlclientlib


Gem files will remain installed in /home/user/.rvm/gems/ruby-1.9.2-head/gems/mysql2-0.3.7 for inspection.
Results logged to /home/user/.rvm/gems/ruby-1.9.2-head/gems/mysql2-0.3.7/ext/mysql2/gem_make.out
An error occured while installing mysql2 (0.3.7), and Bundler cannot continue.
Make sure that `gem install mysql2 -v '0.3.7'` succeeds before bundling.

Fix:

sudo apt-get install libmysqlclient-dev

rvm 1.9.2-head gem install mysql2

Sunspot issue - You need a Java Runtime Environment to run the Solr server

C:\Users\project1>rake sunspot:solr:run --trace
DEPRECATED! (configure_from_yaml) Please stop using YAML and use Ruby instead. T
his method will be removed in 2.9.
** Invoke sunspot:solr:run (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute sunspot:solr:run
The syntax of the command is incorrect.
rake aborted!
You need a Java Runtime Environment to run the Solr server

Fix:
Modify C:\Ruby192\lib\ruby\gems\1.9.1\gems\sunspot_solr-1.3.0\lib\sunspot\solr\java.rb file with

module Sunspot
  module Solr
    module Java
      def self.installed?
          true
      end
    end
  end
end

Also make sure your gemfile has:

gem 'sunspot_rails'
# This is an optional packaged Solr:
group :test, :development do
  gem 'sunspot_solr'
end

Reference Links:
https://github.com/sunspot/sunspot/issues/147

Useful links to install redis on windows

Download and install:
https://github.com/rgl/redis/downloads
References:
https://github.com/dmajkic/redis http://redis.io/documentation
You may need this as well:
http://www.mingw.org/wiki/Getting_Started http://sourceforge.net/projects/mingw/files/Installer/mingw-get-inst/mingw-get-inst-20111118/