Intridea

I am excited to join forces with my friends in DC and work on some kick-ass Rails projects. Intridea has grown very fast in less than a year. Almost 15 Rails developers now.

I just ordered 30 inch Mac Cinema Display. I will be working from home, which will be fun and much more productive than going to an office. Finally no distractions and stupid meetings!!!

swf chart vs gruff

Need to evaluate them when I get some time. Requested Geoff to produce a screencast on Selenium on Rails. He responded back after a few days saying he has to learn it and has included it in this todo list.

Ruby Idioms Presentation

Here is the link to the presentation. Thanks to Pelle for his review on his website.

How to use Will Paginate 2.0 Rails plugin

Step 1: In the controller:
@users = User.paginate(:order => 'created_at DESC'
:conditions => ["active = ?", 1]
:per_page => 10,
:page => params[:page])

Step 2: In the view:
<%= will_paginate @users, :inner_window => 10, :outer_window => 10 %>

This will create page links from 1 to 10 then dots followed by numbered links for last 10 pages.

Step 3: To make the pagination links sexy, copy the following CSS (Digg style):

div.pagination {
padding: 3px;
margin: 3px;
}

div.pagination a {
padding: 2px 5px 2px 5px;
margin: 2px;
border: 1px solid #AAAADD;

text-decoration: none; /* no underline */
color: #000099;
}
div.pagination a:hover, div.pagination a:active {
border: 1px solid #000099;

color: #000;
}
div.pagination span.current {
padding: 2px 5px 2px 5px;
margin: 2px;
border: 1px solid #000099;

font-weight: bold;
background-color: #000099;
color: #FFF;
}
div.pagination span.disabled {
padding: 2px 5px 2px 5px;
margin: 2px;
border: 1px solid #EEE;

color: #DDD;
}

Reference: Err the blog.

San Francisco Ruby Meetup

I presented my Ruby Idioms today at the San Francisco Ruby Meetup. It was my first presentation and I was very excited. It was full of examples and practical tips. Some of the idioms were described in the context of Rails applications. Soon I will be posting the link to the actual presentation in pdf format. Enjoy!

Rails Performance Notes

Static Caching

- Cache on demand through Rails
- Cron sweeper (minute.rb?)
- JS + cookie for username
- Caching functional test
- ngnix config (run it locally for testing?)
- deploying cron job


Performance

1. Query optimization - query analysis (doing n queries instead of joins)
2. Rails static page caching
3. Asset packager - Firebug Net tab (Page lead times, "apparent" performance)
4. Number of optimal Mongrels ( Topfunky screencast )
5. Rails log - Page load times, Query times
6. Unix diagnostics
- Top
- Vmstat
- MySQL tools
- tail / grep etc
7. Periodic reporting
8. Benchmarks

PostgreSQL on Mac OS

MySQL suddenly stopped working and I was not able to run it. I got frustrated with MySQL error messages like no /tmp/mysql.sock found and -bash: /usr/local/mysql/bin/mysql: Bad CPU type in executable

22:04:59:/usr/local/src > mkdir postgres
22:05:24:/usr/local/src > cd postgres/
22:05:27:/usr/local/src/postgres > ls -l
22:05:29:/usr/local/src/postgres > curl -O ftp://ftp5.us.postgresql.org/pub/PostgreSQL/source/v8.2.4/postgresql-8.2.4.tar.gz
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 14.8M 100 14.8M 0 0 48521 0 0:05:21 0:05:21 --:--:-- 77126
22:12:19:/usr/local/src/postgres > tar -xzvf postgresql-8.2.4.tar.gz
postgresql-8.2.4

22:31:26:/usr/local/src/postgres > cd postgresql-8.2.4
22:31:30:/usr/local/src/postgres/postgresql-8.2.4 > ./configure --with-includes=/sw/include/ --with-libraries=/sw/lib
checking build system type... powerpc-apple-darwin8.10.0

22:33:12:/usr/local/src/postgres/postgresql-8.2.4 > make
22:41:07:/usr/local/src/postgres/postgresql-8.2.4 > sudo make install
23:25:46:/usr/local/src/postgres/postgresql-8.2.4 > /usr/local/pgsql/bin/initdb -D /usr/local/pgsql/data

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the -A option the
next time you run initdb.

Success. You can now start the database server using:

/usr/local/pgsql/bin/postgres -D /usr/local/pgsql/data
or
/usr/local/pgsql/bin/pg_ctl -D /usr/local/pgsql/data -l logfile start

23:29:07:/usr/local/src/postgres/postgresql-8.2.4 > /usr/local/pgsql/bin/postgres -D /usr/local/pgsql/data
LOG: database system was shut down at 2007-08-16 23:26:25 PDT
LOG: checkpoint record is at 0/42BEB8
LOG: redo record is at 0/42BEB8; undo record is at 0/0; shutdown TRUE
LOG: next transaction ID: 0/593; next OID: 10820
LOG: next MultiXactId: 1; next MultiXactOffset: 0
LOG: database system is ready

23:35:06:~ > /usr/local/pgsql/bin/createdb
CREATE DATABASE
23:35:33:~ > /usr/local/pgsql/bin/createdb mytestdb
CREATE DATABASE
23:35:45:~ > /usr/local/pgsql/bin/psql mytestdb
Welcome to psql 8.2.4, the PostgreSQL interactive terminal.

Type: \copyright for distribution terms
\h for help with SQL commands
\? for help with psql commands
\g or terminate with semicolon to execute query
\q to quit

mytestdb=# create table foo(name varchar primary key, foo_id serial);
NOTICE: CREATE TABLE will create implicit sequence "foo_foo_id_seq" for serial column "foo.foo_id"
NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "foo_pkey" for table "foo"
CREATE TABLE
mytestdb=# insert into foo(name) values ('Liz');
INSERT 0 1
mytestdb=# insert into foo(name) values ('Bunny');
INSERT 0 1
mytestdb=# select * from foo;
name | foo_id
-------+--------
Liz | 1
Bunny | 2
(2 rows)

Acts as Billable Installation

1. script/plugin install http://source.collectiveidea.com/public/acts_as
_billable/trunk/

2. script/plugin install http://activemerchant.googlecode.com/svn/trunk/
active_merchant

3. sudo gem install --source http://dist.leetsoft.com money

4. script/plugin install http://source.collectiveidea.com/public/rails/p
lugins/acts_as_money

Generating Excel files in Rails

1) Nice post on how to export data as a Excel files.

How to add Rails plugin files to SVN during install

use -x flag. Example:

script/plugin install -x http://svn.techno-weenie.net/projects/plugi
ns/restful_authentication/

Recurring Billing in Rails

Research notes:

Dealing with subscriptions payment
Follow-up to subscriptions
Recharging to the Same Credit Card

Sample test case:

def test_reference_purchase
assert response = @gateway.purchase(Money.new(10000), @creditcard, @options)
assert_equal "Approved", response.message
assert response.success?
assert response.test?
assert_not_nil pn_ref = response.authorization

# now another purchase, by reference
assert response = @gateway.purchase(Money.new(10000), pn_ref)
assert_equal "Approved", response.message
assert response.success?
assert response.test?
end

Acts As Billable Plugin

script/plugin install http://source.collectiveidea.com/public/acts_as_billable/trunk/
There’s a start of a sample app (that uses rspec) that goes with it at http://source.collectiveidea.com/public/acts_as_billable/samples/depot

Authorize.Net Automated Recurring Billing (ARB) Example Code

ARG Guide

Boyer-Moore string search algorithm in ruby

Fast search of a specific search string.

Help in writing tests in Rails

script/console test

It will load the console in the test environment. Very useful to experiment with the code and write tests.

Railscookbook example error

NameError in User#list_perms

Showing app/views/user/list_perms.rhtml where line #22 raised:

uninitialized constant UserHelper::Permission

create the permission model without migration.

Also the migration for permissions table does not have a id column. This results in a bug where the update does not work for some cases. So I had to add a primary key column to the permissions table. This fixed the buggy update problem.

How to skip migration in Rails

use --skip-migration switch: Ex: script/generate model user --skip-migration

How to format mysql output

select * from table_name limit 1 \G;

How to suppress rendering of layout while generating xml in Rails

def my_xml_method
@foo = Foo.find(:all)
render :layout => false
end

If you have render and respond_to in the same method, you will get the dreaded double render error.

How to install RubyInline in Mac OS

$ sudo gem install rubyinline
Successfully installed RubyInline-3.6.3
Installing ri documentation for RubyInline-3.6.3...
Installing RDoc documentation for RubyInline-3.6.3...

Port install did not work:

sudo port install rb-rubyinline
---> Fetching autoconf
---> Attempting to fetch autoconf-2.61.tar.bz2 from http://ftp.gnu.org/gnu/autoconf
---> Verifying checksum(s) for autoconf
---> Extracting autoconf
---> Configuring autoconf
---> Building autoconf with target all
---> Staging autoconf into destroot
---> Installing autoconf 2.61_0
---> Activating autoconf 2.61_0
---> Cleaning autoconf
---> Fetching rb-rubygems
---> Attempting to fetch rubygems-0.9.4.tgz from http://rubyforge.org/frs/download.php/20989/
---> Verifying checksum(s) for rb-rubygems
---> Extracting rb-rubygems
---> Configuring rb-rubygems
Error: Target com.apple.configure returned: configure failure: shell command " cd "/opt/local/var/db/dports/build/_opt_local_var_db_dports_sources_rsync.rsync.darwinports.org_dpupdate_dports_ruby_rb-rubygems/work/rubygems-0.9.4" && /opt/local/bin/ruby -rvendor-specific setup.rb config " returned error 127
Command output: sh: line 1: /opt/local/bin/ruby: No such file or directory

Error: The following dependencies failed to build: rb-hoe rb-rake rb-rubygems rb-rubyforge
Error: Status 1 encountered during processing.

How to use select_tag to create drop down menus in Rails

<%=
select_tag :size, options_for_select(["Small", "Medium", "Large"])
%>

This will create a drop down with the values in the array. You can either declare a constant array in the model and use that like: MyModel::SHIRT_SIZES instead of hard coding it. If it is database driven, write a helper that will return an array of options.

How to find the helper methods for RESTful nested routes in Rails

1) script/console
2) >> irb ActionController::Routing::Routes
3) rs = ActionController::Routing::Routes
4) rs.named_routes.each {|name, route| puts( name, route) }; 1
5) Just copy the list of helper methods show in the output of step 4 and append path to that name. You must also provide the required ids shown in the output. For example take the output:

user
GET /users/:id/ {:action=>"show", :controller=>"users"}

and in the console, type:

>> user_path 1
=> "/users/1"

The same process can be used for nested routes.

Reference: Rails Routing by David A Black. This book gave me a solid understanding of routes.