Caching in Rails

Rails has wonderful inbuilt caching methods. This is how i implemented caching for a particular action. 

 Requirement : Cache a page for 12 hours. After 12 hrs Caching must expire.

  before_filter :clear_cache
  caches_action :index, :layout => false

def index  
    #code
    # Write expiry time to cache (12 hours)
    Rails.cache.write('expiry_time', Time.now + 12.hours)
end


def clear_cache
    #Fetch time from cache and check with current time
    t = Rails.cache.fetch('expiry_time') || Time.now
    t = Time.parse(t) if t.is_a?(String)
    # Expire action if current time > Cached time
    expire_action :action => :index if Time.now > t
 end

Thanks!

Roles implemented with easy_roles plugin

Plugin git repo : https://github.com/platform45/easy_roles 

 

Step 1 : Install Plugin

script/plugin install git://github.com/platform45/easy_roles.git

Step 2 : Generate migration to create column called roles in user's table

rails g easy_roles user roles

Step 3 : Run. rake db:migrate to run the migration

Step 4 : Add this line to the user's model

class User < ActiveRecord::Base
  easy_roles :roles
end

Add users role, remove, check role as follows.

@user = User.first 

@user.add_role 'admin' 

@user.is_admin? 

=> true 

   

@user.has_role? 'admin' 

=> true 

 

@user.is_awesome? 

=> false 

 

@user.add_role 'awesome' 

 

@user.is_awesome? 

=> true 

 

@user.remove_role 'admin' 

 

@user.is_admin? 

=> false 

How to fix Unrecognized command line argument: 'package'

>> rvm package install zlib
ERROR: Unrecognized command line argument: 'package' ( see: 'rvm usage' )

The keyword 'package' is renamed to 'pkg'


Try,


>> rvm pkg install zlib


Njjoy :)

How to fix 'make' is not recognized as an internal or external command

Hi,

I have got this below error.

$ gem install rhodes-3.1.0.gem -l

Building native extensions.  This could take a while...

ERROR:  Error installing rhodes-3.1.0.gem:

        ERROR: Failed to build gem native extension.

c:/InstantRhodes/ruby/bin/ruby.exe extconf.rb

make

'make' is not recognized as an internal or external command,

operable program or batch file.

Gem files will remain installed in c:/InstantRhodes/ruby/lib/ruby/gems/1.8/gems/

rhodes-3.1.0 for inspection.

Results logged to c:/InstantRhodes/ruby/lib/ruby/gems/1.8/gems/rhodes-3.1.0/ext/

gem_make.out

Here is the Fix:
install Devkit for windows by following the steps,
https://github.com/oneclick/rubyinstaller/wiki/development-kit

--
Srikanth

Rhodes + Blackberry + Fixing error + No such file or directory Simulator

 Hi,

I have got this error No such file or directory 'Simulator'

ltadmin@LT008029 ~/projects/SocialTango_Mobile (master)

$ rake run:bb

rake/rdoctask is deprecated.  Use rdoc/task instead (in RDoc 2.4.2+)

$use_sqlite : false

rake aborted!

No such file or directory - C:/bb/5.0.0.621_9650/simulator

This is how to Fix this,

Fix 1. Check if you have installed the Blackberry JDE. If you have installed Blackberry JDE there will be a simulator folder and MDS folder inside the installed directory. (In case if you have not installed JDE, here is where you need to download http://us.blackberry.com/developers/javaappdev/javadevenv.jsp)

Fix 2. If you have installed JDE and got the error. Go to Rhodes installation path and find the rhobuild.yml. In my system the path is,

C:\InstantRhodes\ruby\lib\ruby\gems\1.8\gems\rhodes-3.0.2\rhobuild.yml 

check if this paths are correct in rhobuild.yml:

    6.0:
      jde: C:/Program Files/Research In Motion/BlackBerry JDE 6.0
      mds: C:/Program Files/Research In Motion/BlackBerry JDE 6.0/MDS
      sim: 9800

Installing Rhodes, Running app in Blackberry Simulator in windows

1. Download the Instant Rhodes installer from http://docs.rhomobile.com/rhodes/install#install-on-windows and install it.  This will install Ruby, Rhodes.

2.  Download the Blackberry JDE from http://us.blackberry.com/developers/javaappdev/javadevenv.jsp

 Note :  For this you will need to create account and login to the blackberry website.

3. Create a sample rhodes app. 

rhodes app myspace

4. Go to build.yml in the app, and change the version for blackberry,. 

bbver: 6.0

5. do 'rhodes-setup' for adding Java path  

$ rhodes-setup
We will ask you a few questions below about your dev environment.
JDK path (required) (C:/Program Files/Java/jdk1.6.0_21): C:/Program Files/Java/j
dk1.6.0_21

for other paths just skip. 

6. Go to Rhodes installation path and find the rhobuild.yml. In my system the path is,

C:\InstantRhodes\ruby\lib\ruby\gems\1.8\gems\rhodes-3.0.2\rhobuild.yml

add this lines in rhobuild.yml for blackberry version 6.0

    6.0:
      jde: C:/Program Files/Research In Motion/BlackBerry JDE 6.0
      mds: C:/Program Files/Research In Motion/BlackBerry JDE 6.0/MDS
      sim: 9800

7. Run the app., rake run:bb

This opens blackberry simulator. Now find your app in the apps menu.

Cheers!

Rhodes + Setup Android in windows + problems

Error 1 :

invalid command-line parameter: Files\Android\android-sdk\tools/emulator-arm.exe.
Hint: use '@foo' to launch a virtual device named 'foo'.
please use -help for more information

Fix: 
This problem is when you install Rhodes in the path "c:/Program Files/Android/android-sdk"  as there is a space in the word "Program Files". Try reinstalling to path "c:/Android/android-sdk"

Error 2 : 
sh.exe": /c/InstantRhodes/ruby/bin/rake: C:/RhoSync/ruby/bin/ruby.exe^M: bad interpreter: No such file or directory

Fix : reinstall the rake gem.

1. gem uninstall rake
2. gem install rake

This will update the rake Gem


Error 3 : Cannot find your Rhodes gem or source path.

 Fix :  run this in terminal. this will set up the rhodes path

$ set-rhodes-sdk
c:/InstantRhodes/ruby/lib/ruby/gems/1.8/gems/rhodes-3.0.2/bin