RORLAMP Development

Just installed a new precise pangolin and thought of giving rbenv a try….

So collected this with a bit of googling….

rbenv is a new lightweight Ruby version management tool built by Sam Stephenson(of 37signals and Prototype.js fame).

The established leader in the Ruby version management scene is RVM but rbenv is an interesting alternative if you want or need something significantly lighter with fewer features. Think of it as a bit like Sinatra and Rails. It’s not about which is the best, it’s about which is better for you and your current requirements.
What’s rbenv?

Compared to RVM, rbenv is light. For example, it doesn’t include any mechanism to install Ruby implementations like RVM does. Its sole job is to manage multiple Ruby “environments” and it allows you to quickly switch between Ruby implementations either on a local directory or default ‘system-wide’ basis.

With rbenv, you install Ruby implementations manually or, if you prefer a little help, you can try ruby-build, another project of Sam’s that provides RVM esque recipes for installing seven popular Ruby implementation and version combos.

rbenv primarily works by creating ‘shim’ files in ~/.rbenv/shims which call up the correct version of files for each Ruby implementation behind the scenes. This means ~/.rbenv/shims will be in your path and there’s no threat of incompatibilities between libraries or systems like Bundler and rbenv.

The key thing to be aware of, however, is that if you install a gem that includes ‘binaries’ (or any generally available command line scripts), you need to run rbenv rehash so that rbenv can create the necessary shim files.
INSTALLATION

Firstly, it’s worth noting that by default rbenv is incompatible with RVM because RVM overrides the gem command with a function. This means to get the full rbenv experience you’ll need to do a rvm implode to wipe away your RVM installation or, at the least, remove/comment out the RVM loader line in your .bash_profile and/or .bashrc.

The installation instructions for rbenv are likely to change fast due to its youth, so I suggest the README. However, rbenv has just been made into a homebrew package on OS X, so if you’re a homebrew user , try:

brew update brew install rbenv rbenv rehash

And then add this line to your ~/.bash_profile or equivalent:

eval “$(rbenv init -)”

When you open a new shell now, you can run commands like rbenv and rbenv version to see what’s going on. rbenv versions should return nothing since you won’t have any rbenv-enabled Ruby installations yet, so move on to the next step..
Installing Implementations for rbenv

If you have ruby-build installed, getting, say, Ruby 1.9.2-p290 installed is easy:

ruby-build 1.9.2-p290 $HOME/.rbenv/versions/1.9.2-p290

If you prefer to download tarballs and do your own Ruby installs, however, you just need to set the directory prefix at the ./configure stage in most cases. For example:

./configure –prefix=$HOME/.rbenv/versions/1.9.2-p290

Once you’ve installed a new Ruby in this way, you need to run rbenv rehash in order for rbenv to create the ‘shim’ binaries necessary to make the correction version of Ruby available on the path at all times.
The RVM Splashback

In the interests of completeness, it’d be amiss to not mention the minor drama that kicked off on Twitter and Hacker News about rbenv’s release.rbenv made its way on to Hacker News where, surprisingly, many people railed against RVM. This, coupled with a slightly antagonistic tone taken by rbenv’s README (which has now been taken away), led RVM’s maintainer Wayne E Seguin to vent some pressure on Twitter:

Sam quickly clarified his position:

Nonetheless, Wayne took a little time off, and a campaign to encourage donations to Wayne for his work on RVM was kicked off on Twitter (by Ryan Bates, I believe). The campaign went well, taking RVM’s donations from $7468 to $11370 (at time of writing), a jump of almost $4000 in a few days.

Part of the complaint made in rbenv’s README was about RVM’s “obnoxious” redefinition of the “cd” shell builtin. Essentially, RVM would create a new function which called “cd” but also took into account any .rvmrc files present in each directory so that it could change Ruby version automatically. While there was some validity to this concern, Ben Atkin took some time to write a blog post correcting some of the misinformation on this point.

In the end, however, all seems to be well, and Wayne is already making regular commits to the RVM project again just days later. Hopefully the outpouring of support from the Ruby community for RVM over the past couple of days has shown Wayne that RVM still has a significant user base, most of who aren’t going anywhere new anytime soon. If you want to help out, of course, you can still donate to the RVM Pledgie.
Conclusion

If you’re happy with RVM, there’s not much in rbenv to really leap to. It’s just a lighter and more modular way to achieve the basic functionality that RVM provides while missing out on a lot more (although you can use rbenv-gemset to get some basic gemset-like features).

If, however, you want something “lighter” than RVM, rbenv is certainly worth a look. Its approach feels cleaner and more transparent at a certain level, and if this is of utmost importance to you, you may prefer it.

I personally switched back to rvm coz I am getting openssl error which is tricky(ofcourse mybad!) and not able to get over it…

It’s 5 in the morning and i am tired and its a possibility that i may be writing a long post, Last night i asked my self what is it that i have learned in the las t couple of months and out of nothingness i rememberd a VIDEO CHAT APPLICATION which my friend Viren and I worked on. I thought it might be useful for some of you.

When we started, we didnt have enough knowledge where to begin with and had time constraints to meet. We came across solutions like Red5,ErlyVideo. Now our problem was that our client had to be in flash or java applet. So we tried working around many solutions. HTML5 was months away from its release.

we are looking into other HTML5 Features and we get awesome HTML5 web socket support so we thought let’s get some hands on it.

So we think let’s build pubsub chat application, after Googling we got couple of solution.but we want to build own i have choice between nodejs and EventMachine.we have choose EM to quick start.

So we are ready,
We go through HTML5 Web Socket API,and tutorial so basically it’s a technique for two-way communication over one (TCP) socket, a type of PUSH technology.
So it has mainly three events

1. onopen: When a socket has opened
2. onmessage: When a message has been received
3. onclose: When a socket has been closed

More info regarding HTML5 Web Socket you can visit Nettuts, HTML5Demo.
lya Grigorik has written awesome library,and article on it so i don’t go in much detail.

Steps we are following

• When User is connected onopen event is fired and  we create one default connection and add to pool of channels,it’s used for mainly notification purpose

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Hey all,
In Previous article i have given short bio of ruby daemon using daemon kit.
In this post i am writing about how to manage daemon,how to start/stop a daemon from any directory.

We can start a daemon using following way.
Go to the directory and give the command.

./bin/mydaemon

or

./bin/mydaemon start

(You know the difference right; To run it in foreground or background respectively.)

But consider this possibility, what if you didn’t want to go to the directory where the daemon is located and start it.

/home/mysystem/mydaemon/bin/mydaemon

or

/home/mysystem/mydaemon/bin/mydaemon start

Now you might be thinking why you will want to do that, let me say such conditions does arise (when you want monit to watch over it and restart it when it goes down.)

Usually this would work with ease if you are not using a bundler, however if you are using it then this would be something that you would get to see.

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gem install daemon-kit

daemon-kit -h

daemon-kit mydaemon

daemon-kit mydaemon -i amqp</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">daemon-kit mydaemon -i cron

cd mydaemon</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">./bin/mydaemon

./bin/mydaemon start

./bin/mydaemon stop

</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">my_cron_daemon</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">├── bin</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   └── my_cron_daemon</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">├── config</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   ├── arguments.rb</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   ├── boot.rb</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   ├── environment.rb</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   ├── environments</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   │   ├── development.rb</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   │   ├── production.rb</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   │   └── test.rb</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   ├── post-daemonize</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   │   └── readme</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   └── pre-daemonize</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│       ├── cron.rb</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│       ├── readme</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│       └── safely.rb</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">├── Gemfile</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">├── lib</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   └── my_cron_daemon.rb</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">├── libexec</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   └── my_cron_daemon-daemon.rb</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">├── log</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">├── Rakefile</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">├── README</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">├── script</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   ├── console</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   ├── destroy</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   └── generate</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">├── spec</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   ├── my_cron_daemon_spec.rb</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   ├── spec_helper.rb</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   └── spec.opts</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">├── tasks</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">│   └── rspec.rake</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">├── tmp</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">└── vendor</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

excluded_files = [File.join(DaemonKit.root, 'lib', "my_cron_daemon.rb")]</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">(Dir.glob(File.join(DaemonKit.root, "lib", "*.rb")) - excluded_files.flatten).each{|f| require f}

CONFIG = DaemonKit::Config.load("config.yml")

ActiveRecord::Base.configurations = CONFIG[:database_configuration]</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">ActiveRecord::Base.establish_connection(CONFIG[:database_configuration])

DaemonKit.logger.info "I am the DaemonKit logger info"

Hey all,

Many of us knows what daemons are in linux. These are processes or programs that run in background with little or no user intervention.

Now we can write daemons in ruby too. And for doing so we can use Daemon-Kit.

Now the daemon can do the task continuously or do it at particular interval of time or do it depending on a particular event.

Daemon-Kit provides a skeleton to write these different types of daemons with the help of differnt types of generators.(XMPP bot,AMQP client,Nanite agent,Cron-style,ruote remote participants). Of these XMPP and AMQP are event based and amqp is specifically based on queuing system, and Nanite agent gives a nanite structured daemon while Cron-style is used to write daemons that perform certain task at particular interval amount of time.

First install the gem daemon-kit

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Just quick post how to use acts_as_flying_saucer with rails 3.1 and Heroku.

I was testing acts_as_flying_saucer with rails 3.1.It is working fine so far,but when i have added external style sheet it was hanging on dev mode rails is hanging

After litte bit of googling  i figure out it is external style sheet causing an issue because of asset pipeline and thread issue for serving static file mainly in dev mode.

So i simply pre complied css or we can manually (actual full path) or manipulate asset path .after this PDF is generated properly.

Now it is time to test on Heroku.I am using cedar stack and ruby 1.9.2 after pre complied step.

Now point tmp directory to application tmp directory.

ActsAsFlyingSaucer::Config.options = {:tmp_path => "./tmp"}

It’s about more than 6 months i haven’t written any post Why ?

because recently join new organization, and can’t get much more time , we are working almost more than 10 to 12 hr day with messy code.So we are spending more time to  refactoring and optimizing code,and scaling application.

In my current organization we are generating various PDF report.We are using prawn but now we are switching to acts_as_flying_saucer.

So there are couple of challenges i have faced

1. XHTML code is not proper
2. Special character in html

Solution: Cleanup Html code

Continue reading »

Well long break,Let me guess It over 3 month since I wrote my last post. I’ve been kind of  busy lately not manage to dedicate much time to thing that I do.

Rails 3.1.0 is been in picture for a quite a while a now and major feature that been included in Rails 3.1.0 is asset pipeline and pre-processor.

For those is who aren’t aware of Rails 3.1.0 asset pipeline and pre-processor there is a very good article on rails guide and recently Ryan Bates introduce a screencast on Rails 3.1.0 asset pipeline.

I’m not here to talk about asset pipeline you can get it all if you just googled it.

So what I’m here upto then ?

Well ever since I was made aware of what asset pipeline  and pre-processor more importantly pre-processor ,it always trilled me of using a custom pre-processor .

As you all know that Rails 3.1.0.rc1 is bundle with coffee-script and sass support. In your asset folder you may find js and css file that look something like this “*.js.coffee” , “*.css.scss“. Now you can add a chain of pre-processor that just look like this “*.js.coffee.erb” , “*.css.scss.erb”

The post is all about chaining your own pre-processor just as above something like “*.js.coffee.mustache”

Mustache (Mustache is taken just for example here you can use your own) because I been in love with it ever since I explored it . So how to accomplish this .

Stay with me as I will show how ?

Firstly you need to be aware of Sprockets and Tilt library

First the code

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There are various library for manipulating image,one of them is GD library.
In this post i quickly show how to resize an image or generate thumbnail of image using GD2.

Basic steps as follows

1. First import image
2. Resize an import image to desired size
3. Export Image to desired file

above code is extracted from rchart.

I have to admit this . I always fall in love with RAILS each day as I explore it to know how a complex problem can be handle with great ease and with minimum amount of code.

That what made me write this post on " Conditional Get Request."
For those who aren’t aware of it let me give them some insight in it.

Conditional GETs are a feature of the HTTP specification that provide a way for web servers to tell browsers that the response to a GET request hasn’t changed since the last request and can be safely pulled from the browser cache.

They work by using the HTTP_IF_NONE_MATCH and HTTP_IF_MODIFIED_SINCE headers to pass back and forth both a unique content identifier and thetimestamp of when the content was last changed. If the browser makes a request where the content identifier (etag) or last modified since timestamp matches the server’s version then the server only needs to send back an empty response with a not modified status.

Enough of talk now its  time for the action (Way to achieve it in Rails)

class UsersController < ApplicationController
 def show
   @user = User.find(params[:id])
    fresh_when :last_modified => @user.last_updated_at ,:etag => @user
 end
end

That it done

Now let check the logs to find, does it actually asking browser to read from its cache.

First time the page will completely render but any subsequent query for the same page will ask the browser to display from its cache(browser cache) (until modified).

Here my log :-

Other way to achieve the same is.

 def show
   @user = User.find(param[:id])
    if stale?(:last_modified_at => @user.updated_at,:etag => @user)
      repsond_to do |format|
        format.html
      end
    end
end

 def show
   @user = User.find(params[:id])
    response.last_modified = @user.updated_at
    response.etag = @user
    if request.fresh?(response)
      head :not_modified
    else
      respond_to do |format|
        format.html
      end
    end
 end

The Following Code should give you same result as above

That it , thats all it take to get " Conditional GET " working in Rails. Wasn’t I right when I said that I fall in love with Rails each day.

Usage :-

Now most of you  might be wondering where can they employ this technique or when should they use it

My Answer to them is think of Conditional Get a kind of Caching Mechanism ( after that what browser is doing for you)

Now suppose you have a method in controller that make large number of Database queries or ERB template that render a lot of contents on per requests .Wrapping the same with " Conditional GET " can simply do a lot of good.

That it enough on " Conditional GET " . Hope the post help you in some way or other.

Thank You .

In my recent work i have face some difficulties for generating different report for different organization or client using same application,because every client have their own reporting format.

Like SAAS based application if it is generate some MIS report and if client require some more or less information depending upon his requirement we can give some editable facilities to edit and generate report.

So to fulfill this kind of requirement user editable report which contains Markup + ruby code for reporting purpose.
I am using liquid ,acts_as_flying_saucer,rchart,textile/Html for generating report.

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