Saturday, April 25, 2009

No More Updating this blog

Hey all

I have shifted by blog on So for latest information that you dont find here.. Please visit my new blog where you will get much more information.

We have started a new Social Stock Market Portal to help investors take informed decision before buying and selling a stock.


Dhaval Parikh
Software Engineer
Ruby on Rails

Wednesday, December 10, 2008

Spam filtering in rails using Akismet

SPAM!!!! is a very big problem for all big applications. If you are having a site which allows users to comment on ur posts and so on then you might get affected by spamming.

Akismet is something which is helping us to avoid spamming on our sites.

There is a rails plugin available at

You can download this and configure akismet in your rails app. more information is provided in read me file of the plugin.

IF you want to see the actual implementation you can watch a screencast on

Hope this is some useful information for you.

Tuesday, December 9, 2008

Counter Cache in rails 2.1

Counter cache is really an important feature in rails 2.1 . This method is really helpful when u want to keep a count on something and avoid firing sql query every time which results in more processing times.

Here it goes

To activate this feature, you need to take two simple steps. First, add the
option :counter_cache to the belongs_to declaration in the child table.

class LineItem < counter_cache =""> true

Second, in the definition of the parent table (products in this example) you
need to add an integer column whose name is the name of the child table with
_count appended.

create_table :products, :force => true do |t|
t.column :title, :string
t.column :description, :text
# ...
t.column :line_items_count, :integer, :default => 0

Thats it .. Counter cache is enabled now.

Thursday, November 20, 2008

Memcached with nginx on rails

As promised in my last article i m posting the way to configure memcached with nginx. Nothing much to do again

Download memcached from you might also require a memcache lib available on install both of them and the memcached command will be available to you

just type in this on the terminal

memcached -p 11211
Thats memcache is on. Just few more changes in the nginx.conf file and you r ready to zoom your rails app

you just need to write this

location /dynamic_request {
# append an extenstion for proper MIME type detection
if ($args ~* format=json) { rewrite ^/dynamic_request/?(.*)$ /dynamic_request.js$1 break; }
if ($args ~* format=xml) { rewrite ^/dynamic_request/?(.*)$ /dynamic_request.xml$1 break; }


error_page 404 = @dynamic_request;


Also you might require to set the uri so do this

set $memcached_key $uri;

Ok thats done no restart nginx service and your memcache + mongrel cluster with gzip on will be running and ur rails app will be zoooooooooooooming


Wednesday, November 19, 2008

Nginx configuration, expiry headers and gzip component with rails - nginx.conf

Just configured nginx server with rails and here is the nginx.conf file. It also includes gzip component and header expiry which is advisable as per the yslow tool.

# user and group to run as

# number of nginx workers
worker_processes 4;

# pid of nginx master process
#pid /var/run/;

# Number of worker connections. 1024 is a good default
events {
worker_connections 1024;

# start the http module where we config http access.
http {
# pull in mime-types. You can break out your config
# into as many include's as you want to make it cleaner
include mime.types;

# set a default type for the rare situation that
# nothing matches from the mimie-type include
default_type application/octet-stream;

# configure log format
log_format main '$remote_addr - $remote_user [$time_local] '
'"$request" $status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';

# main access log
access_log /var/log/nginx_access.log main;

# main error log
error_log /var/log/nginx_error.log debug;

# no sendfile on OSX
sendfile on;

# These are good default values.
tcp_nopush on;
tcp_nodelay off;
# output compression saves bandwidth
gzip on;
gzip_buffers 16 8k;
gzip_http_version 1.0;
gzip_comp_level 9;
gzip_proxied any;
gzip_types text/plain text/css application/x-javascript text/xml application/xml application/xml+rss text/javascript application/javascript application/css;

# this is where you define your mongrel clusters.
# you need one of these blocks for each cluster
# and each one needs its own name to refer to it later.
upstream mongrel {

# the server directive is nginx's virtual host directive.
server {
# port to listen on. Can also be set to an IP:PORT
listen 80;

# Set the max size for file uploads to 50Mb
client_max_body_size 50M;

# sets the domain[s] that this vhost server requests for

# doc root
root /sites/sitename/public;

# vhost specific access log
access_log /var/log/nginx.vhost.access.

log main;

# this rewrites all the requests to the maintenance.html
# page if it exists in the doc root. This is for capistrano's
# disable web task
# if (-f $document_root/system/maintenance.html) {
# rewrite ^(.*)$ /system/maintenance.html last;
# break;
# }

location / {
# needed to forward user's IP address to rails
proxy_set_header X-Real-IP $remote_addr;

# needed for HTTPS
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_redirect false;
proxy_max_temp_file_size 0;

if (-f $request_filename) {
expires max;

# If the file exists as a static file serve it directly without
# running all the other rewite tests on it
if (-f $request_filename) {

# check for index.html for directory index
# if its there on the filesystem then rewite
# the url to add /index.html to the end of it
# and then break to send it to the next config rules.
if (-f $request_filename/index.html) {
rewrite (.*) $1/index.html break;

# this is the meat of the rails page caching config
# it adds .html to the end of the url and then checks
# the filesystem for that file. If it exists, then we
# rewite the url to have explicit .html on the end
# and then send it on its way to the next config rule.
# if there is no file on the fs then it sets all the
# necessary headers and proxies to our upstream mongrels
if (-f $request_filename.html) {
rewrite (.*) $1.html break;

if (!-f $request_filename) {
proxy_pass http://mongrel;



error_page 500 502 503 504 /500.html;
location = /500.html {
root /sites/sitename/public;


In my next article i will also post how to configure memcache with rails and nginx

Monday, November 17, 2008

Load Balancing with pound and Mongrel Clustering

In my previous post I have written about mongrel clustering..

Now if you want to add the load balancing feature to it you may use pound. Pound is a software HTTP Load Balancer and Reverse Proxy.

These are the steps how you can configure pound with mongrel cluster. First configure mongrel cluster as per the previous post.

Then download and install pound from

Now the configuration step

Pound.cfg needs to be configured which will reside in /etc/pound/pound.cfg

also a symlink is required to be made

$ sudo ln -s /etc/pound/pound.cfg /usr/local/etc/pound.cfg

A basic version of pound.cfg will look something like this

User "www-data"
Group "www-data"
LogLevel 2
Alive 30

Port 80

HeadRequire "Host:.**"
Port 8080
TTL 300

URL ".*.mov"
Port 8081
TTL 300

# Catch All
Port 9000
Port 9001
TTL 300

Then start pound with the following command

$ sudo /etc/init.d/pound start

finally you will have mongrel cluster setup done so start mongrel cluster

sudo mongrel_rails cluster::start

Thats it you mongrel cluster with pound configuration is done..
njoi the power of load balancing

Saturday, November 8, 2008

Mongrel Clustering with Rails

Hey every one wants to make their site run faster..and there are many ways like caching (page caching, fragment caching, method caching) so on. One other way is using mongrel cluster which will run multiple instance of mongrel on you server which will help to improve website speed to a huge extent.

Let me tell you the steps for doing mongrel clustering .. its really easy..

Step 1 : - Install mongrel cluster gem

sudo gem install mongrel_cluster

Step 2 : - configure cluster and run the config file which will reside in config/mongrel_cluster.yml

mongrel_rails cluster::configure -p 8000 -e production -a

Well thats it now here you go

Start the cluster:
mongrel_rails cluster::start

Restart the cluster:
mongrel_rails cluster::restart

Stop the cluster:

mongrel_rails cluster::stop

Well just try these steps and if you are not able to configure it just post a
comment and i will get back to you.

Enjoy better speed :)

Wednesday, September 17, 2008

Page Screenshot in Rails

Have you ever been through a situation where you need to embed a Flash object or some other element in a pdf file which cant be done directly? There is gr8 solution for it

with the help or combination of RMagick + Image Magick + win32Screenshot gem you can take the screenshot of the desktop or webpage and generate an image from it and eventually embed it in your pdf file

Here is the code for it

require 'win32screenshot'
require 'RMagick'    
def screenCapture     
  width, height, bitmap = Win32::Screenshot.desktop     
  img_lst =     

If you are stuck any where just write to me or post a comment here
I would be pleased to solve your error

Sunday, August 31, 2008

Flex On rails

Hi all

With the increasing number of sites being made in RIA - Rich Internet Applications many people have adopted Rails + Flex for make a Rich Internet Application.

There is a very gr8 plugin or code available on known as ruby on rails ria sdk by adobe. Here is the url for it

The Ruby on Rails RIA SDK by Adobe provides developers with samples and code to help develop solutions with Ruby and Adobe technologies. The SDK includes open source code created by third parties as well as samples and demos that have been created by project members.

You can download an initial .zip file containing all the files using the Download link on the right hand side, or you can check out the code via SVN by clicking on the 'Source' tab on the top of the page.

This will help you to get things going and working with Rails + Adobe technology.

Hope this helps


Dhaval Parikh
Software Engineer
Ruby on Rails

Wednesday, August 20, 2008

Latest RoR plugins

Hi all

I am creating this post for all those who wants to get updated regarding whats demanding in RoR and which are the new plugins which will eventually make their coding easier and faster...

So as and when i will come across such link or sites or plugins I will be updating so keep visiting this page...

Also I might have implemented these plugins and would be if you have any problem in implementing them do write a mail to me.

1) Dynamic Tags with RoR :- Tagging for faster search and

2) Open id integration with Rails :- A plugin that makes openid super simple.

3) Google Sitemap :- A google sitemap plugin for rails websites. It generates dynamic sitemaps based on your models and named routes. It has a full mvc stack that you can configure.

4) attachment_fu_app_engine : - Extension for AttachmentFu ( which uses the Google App Engine for storage and image resizing. Allows you to add or change thumbnail sizes without migrating previous data and removes the need to install ImageMagick.

Here are few new additions which I found useful have a look @ them

1) RQuote :- Gets realtime stock quotes from Yahoo Finance. download and njoi very easy to implement

2) Mobile_fu :- If Want to automatically detect mobile devices that access your Rails application? Mobile Fu allows you to do just that. People can access your site from a Palm, Blackberry, iPhone, Nokia, etc. and it will automatically adjust the format of the request from :html to :mobile.

script/plugin install git://

3) Act As nice url :- This acts_as extension provides the
capabilities for creating a nice url based on an attribute of the current object.
You can set / unset the object id in front of the URL and choose the object
attribute to use to generate the URL.
more to go.. Even you can post good plugins which are new by commenting on this post


Dhaval Parikh
Software Engineer
Ruby on Rails