Take a Looksee at how a Ruby Object got its Methods

Monday, July 27, 2009

One property of the Ruby object model and object oriented programming in general is that a subclass of an object automatically inherits all of the methods of its superclass. Classes can further expand the number of methods available by mixing in a Module, or several.

Because of mixins and subclassing even a class that has declared just a few methods can actually have hundreds of methods on it. In Ruby, all classes subclass Object by default which declares a hefty 45 methods, guaranteeing you to have at least that many. Out of the box in 1.8.7, a Ruby String object has 176 instance methods. If you are programming on top of the Rails framework, ActiveSupport adds 98 methods bringing the total to 274!

On numerous occasions I have needed to see what methods are available on an object I am working with I will type the following in irb.

myobject.methods - Object.instance_methods

This prints out a large array of instance methods with the methods inherited from Object removed from the list. This is useful but what if the object I am working with mixed in several modules and I am left with a list of over a hundred methods? It would be great to view which Class or Module each method came from. Well, actually there’s a gem for that.™

Looksee

Looksee is a new gem by George Ogata that examines the method lookup path of any object. To use it add require 'looksee/shortcuts' to your ~/.irbrc. This will add a lp (”lookup path”) method to your irb environment. When passed an object lp prints out a colored display showing where each of an object’s methods lives.

looksee output for a string object

public methods are show in green
protected methods are show in yellow
private methods are show in red
overwritten methods are show in gray

Go ahead and install Looksee and play around with it for a moment. Run lp on a String in vanilla irb and then open script/console in a Rails project and do the same thing. It is quite eye-opening to see the additions that the Rails framework makes.

Standup 07/24/2009: Corrupt Fixture Files

Pivotal Labs

Friday, July 24, 2009

Ask for Help

“We are attempting to upgrade one of our projects using Fixture Scenarios to Rails 2.3.2. When we attempt to run our tests we get errors about a corrupt fixture file. Is anyone successfully using Fixture Scenarios with Rails 2.3?”

Interesting Things

It is really easy to declare an additional route just for use in a controller test. All that is needed is to recall ActionController::Routing::Routes.draw at the top of your spec file. One situation in which this can be useful is if you are creating a new controller just for testing purposes.

class DummiesController < ApplicationController
  before_filter :require_profile

  def index
  end
end

ActionController::Routing::Routes.draw do |map|
  map.resources :dummies
end

describe DummiesController do
  ...
end

Standup 07/23/2009: Timeouts with AWS-S3

Pivotal Labs

Thursday, July 23, 2009

Ask for Help

“When attempting to upload files with the aws-s3 gem I am receiving a lot of timeouts. This seems to happen with both small and large files. Has anyone run into this before?”

It was hypothesized that this could be the result of a slow internet connection and saturating the upload stream. Does anyone know of a fix for s3 timeouts?

Standup 07/22/2009: Temporarily Redefine a Method

Pivotal Labs

Wednesday, July 22, 2009

Ask for Help

“Is there a good way to temporarily redefine a method on a controller during a functional test?”

Reopening a controller and overriding a method affects all tests in a suite. Is there a good way to redefine a controller method for a single test?

Need a Job? Come Work With Pivotal Clients

Parker Thompson

Wednesday, July 22, 2009

At Pivotal Labs, one of the services we provide is bootstrapping startups, including helping them interview and hire. We currently have clients looking for skilled engineers to build their development teams. This is an excellent opportunity to learn Extreme Programming by working side-by-side with Pivotal’s talented and experienced developers while at the same time getting in on the ground floor of a small and dynamic product team.

Pivotal Labs and our clients place a strong emphasis on Agile development and its many aspects: Pair Programming, Test-Driven Development, rapid iterations, and frequent refactoring. General technical requirements include serious web development experience, and a significant subset of Ruby, Rails, CSS, JavaScript, or MySQL.

Here’s a short description of ekoVenture, oneforty, Honk, and Mavenlink, Pivotal Labs clients currently looking for developers. Their full job postings follow at the end of this post.

ekoVenture is the world’s first social marketplace for adventure, experiential and active travel, a $250 billion market. Utilizing the best social networking
technology on the web, we allow users to share their travel experiences, meet
other travelers, and book trips online in real-time. Our revolutionary marketplace
also features a comprehensive inventory management backend platform for tour
suppliers, enabling them to manage their entire business and sell trips or drive
leads directly online – this is already implemented across 500 tour
suppliers…and adding several each day.

oneforty is a Twitter ecosystem/API venture with considerable traction. oneforty comes with all the excitement and opportunity of a Techstars startup backed by talented and successful investors/advisers who have built some of the best known companies on the web. The founder authored Twitter for Dummies and does tons of press and public speaking and the investors and advisors include Guy Kawasaki, Laura Rippy, Jeff Bennett and many others. oneforty has closed their angel round and is looking for RoR developers fired up about building something that will be highly visible and well-promoted.

Mavenlink is a funded startup that is changing the way people find experts who can help them and is providing the necessary tools to get their work done online. We are founded on the principle that virtually everybody needs qualified professional services that are readily accessible, affordable, and there when they need them. We’ve been working with Pivotal Labs to get our product launched, so we’re serious about being agile and we’ve got the right engineering process in place. This is a unique opportunity to join the Mavenlink team and contribute significantly to the direction of the company. We’re looking for someone who is not only passionate about development, but also shares our vision for the tools and capabilities necessary for making remote work better than working in person for both the client and the maven.

Honk.com is a new online automotive website that will make car shopping fun and social. We will enable consumers to experience a new way to explore new cars. We have partnered with a top social website to deliver this new way of car shopping and are funded by one of the largest media companies in the world. Our small team is made up of an experienced group of humble, efficient, and hyper-passionate individuals who are veterans of the automotive industry and social media space. We are proud of our ego-less culture, one that promotes team thinking, not individual accolades. If you’re interested in helping prove that social media and car buying go hand in hand, social networks serve a bigger purpose than keeping up with one’s day, and a small team can outdo the work of an army – then we may have a seat waiting for you.

If you are interested or for more information please contact each company directly. This is an exclusive service provided to our clients, no external companies or recruiters please.

Full job postings follow.

EkoVenture

We are changing the way people interact with our category of travel and we are
looking for passionate people to join the ekoVenture team. We are a dedicated
team of highly talented and spirited individuals who enjoy an open work
atmosphere. There are no offices, which helps fuel our culture of innovation. At
this stage, we work very long hours and make sacrifices, but all employees have
a stake in the company’s success and the perks are very cool. While the
company is established, this is an early stage opportunity to join a team that is
growing rapidly. Our back-end is fully developed and our consumer website is in
beta.

What we offer:
• Great compensation based upon experience
• Full benefits including 401K
• Paid-time off
• 10 paid holidays a year (in addition to PTO)
• Employee stock option plan

Cool perks, such as:
• Company iPhones, mobile service, and 3G internet connection on laptop
• Required sabbatical time (in addition to paid time off)
• Free adventure vacations anywhere in the world through our suppliers’
complementary employee programs
• A global headquarters with a great view, located in the coolest building in the
city of San Francisco, the Transamerica Pyramid
• Discounted/reimbursed health club memberships at the city’s best facilities
• Quarterly company-sponsored adventure outings
• And much more….

Our platform is built using RoR and is 100% scalable. A lot of companies claim
to deploy Agile software development – but we actually do it. We use a method
that is hard-core Agile, a.k.a. extreme programming, with pair programming,
test-driven development, aggressive re-factoring, daily releases, etc. Our code
base contains thousands of tests and this test coverage is an integral part of our
current and future success. If you already have first-hand experience with Agile,
or are interested in learning Agile through our immersive boot camp, then
ekoVenture is the place for you!

Only those who meet the below criteria need apply to ekojobs@gmail.com

About you:
• Well-versed in RoR with a minimum of one year of experience
• MySQL 5, and Linux or OpenSolaris (preferred)
• JavaScript, CSS, Git, Solr, rspec, Cucumber, Selenium, JsUnit
• BS/CS or equivalent experience
• Experience engineering high-volume, transaction-oriented, consumer-facing
web sites
• Self-motivated, takes initiative, innovative and looking to make an impact
• Pairing experience or open to working in a pairing environment
• Not afraid to work long hours, nights, and the occasional weekend
• Broad technical competence
• The ability to understand the business impact of technical decisions
• Extraordinary communication skills

oneforty

oneforty is your opportunity to join highly motivated team to build a high profile, already funded startup and participate in TechStars Boston. Your RoR (and other) engineering skills, intelligence, passion and experience building consumer web startups is your ticket. You will meet amazing people, learn Pivotal Labs-style XP/agile development and build something great that other developers need. oneforty comes with all the excitement and opportunity of a Techstars startup backed by talented and successful investors/advisers who have built some of the best known companies on the web.

oneforty inc. is a Twitter ecosystem/API venture with considerable traction…
* founder authored Twitter for Dummies and does tons of press and public speaking
* selected to participate in the acclaimed TechStars program
* closed our angel round
* starting with the best in the business — Pivotal Labs
* investors and advisors that include Guy Kawasaki, VCs, Laura Rippy, Jeff Bennett and many others.

We’re looking to hire YOU, if…

You have a proven track record working in a fast paced start up that created and managed a highly scalable web platform
You want to build a thriving community and serve other developers
You get things done and are fired up about building something that will be highly visible and well-promoted
You understand the range of related technologies well enough to identify the right tools for the job AND to roll up your sleeves and code well
You have the vision and drive to direct technology decisions and the technical team

Show us your stuff! Tell us what you’ve built and what really gets you fired up.

You will meet and work with name brands in the tech industry. You will build tools and systems that hook up other developers. Your work will provide them with a place to get rewarded by their users and make their stuff shine. Longer-term you could get to build serious tools that serve developers in many API communities.

If this is you, find more details and an online application here or contact laura@oneforty.com. Let us know what you’ve built and how you keep projects organized, well managed and iterating swiftly. Please send us your links: blog, projects, Twitter ID, social media profiles, resume, or anything else you’d like to share.

Mavenlink

We are looking for a Ruby on Rails developer to join our team. We’ve been working with Pivotal Labs to get our product launched, so we’re serious about being agile and we’ve got the right engineering process in place. This is a unique opportunity to join the Mavenlink team and contribute significantly to the direction of the company. We’re looking for someone who is not only passionate about development, but also shares our vision for the tools and capabilities necessary for making remote work better than working in person for both the client and the maven.

Job Description:

Developing Mavenlink’s Ruby on Rails application
Test Driven Development
Pair Programming
Aggressive Refactoring
Using Pivotal Tracker to estimate and knock down stories
Participating in stand-ups and retrospectives to improve

Mavenlink’s product, process, and culture

Additional Skills desired:

HTML/CSS
Javascript & jQuery experience
Experience with rSpec, Webrat, and other testing frameworks
Rails application deployment experience
SQL

Compensation and benefits:

Competitive salary
Equity stake
Full medical and dental

Interested? Send your resume to jobs@mavenlink.com

Honk

Honk.com is a new online automotive website that will make car shopping fun and social. We will enable consumers to experience a new way to explore new cars, focusing on what other real people actually think, not product specifications or biased editorial. Our site will be 100% consumer driven with no journalists or former race car drivers telling you what minivan or sedan you should purchase. Instead, users will find real people like yourself sharing their opinions and experiences. We have partnered with a top social website to deliver this new way of car shopping and are funded by one of the largest media companies in the world. Thankfully, our partners allow (and encourage) us to remain financially independent, unpolitical, and fast-moving… a true start up.

Our small team is made up of an experienced group of humble, efficient, and hyper-passionate individuals who are veterans of the automotive industry and social media space. We are proud of our ego-less culture, one that promotes team thinking, not individual accolades. If you’re interested in helping prove that social media and car buying go hand in hand, social networks serve a bigger purpose than keeping up with one’s day, and a small team can outdo the work of an army – then we may have a seat waiting for you.

Honk is developing a platform of distributed applications and a destination website that will engage consumers’ existing social networks. To be clear, we are not building yet another community or social network. Many of our social applications will reside on our partners’ sites with the intent to drive users to honk.com for a richer experience, including unique content, interaction, and transaction-oriented tools. Our integration with our core partner is currently underway and our beta launch is scheduled for 5/27. We will continue to expand our product over the next twelve months. In addition to deep knowledge of Ruby on Rails and Agile / Test-Driven Development precepts, we hope you have a thorough understanding / are comfortable with:

Amazon S3/SQS/EC2
CSS/Javascript/JQuery
Thin/NGinx/Mongrel
RSpec/Webrat/Selenium
CSV and XML data feed integration

Previous experience working in online automotive or social media is desired, but definitely not required. Honk is currently co-located in San Francisco and Los Angeles. Honk headquarters is currently located in West Los Angeles, right on the border of Santa Monica. Our ideal candidates should reside in one of these two major metro areas, although we are open to “off site” developers who have the right skills and background.

Please send inquiries to Bruce Krysiak, CTO: techjobs@honk.simplicant.com

Introducing ActiveHash, ActiveYaml and ActiveFile – easy readonly, file-based models

Pivotal Labs

Tuesday, July 21, 2009

ActiveHash is a simple base class that allows you to use a ruby hash as a readonly datasource for an ActiveRecord-like model.

ActiveHash assumes that every hash has an :id key, which is what you would probably store in a database. This allows you to seemlessly upgrade from ActiveHash objects to full ActiveRecord objects without having to change any code in your app, or any foreign keys in your database.

It also allows you to use #belongs_to in your AR objects.

ActiveHash can also be useful to create simple test classes that run without a database – ideal for testing plugins or gems that rely on simple AR behavior, but don’t want to deal with databases or migrations for the spec suite.

ActiveHash also ships with:

ActiveFile: a base class that will reload data from a flat file every time the flat file is changed
ActiveYaml: a base class that will turn YAML into a hash and load the data into an ActiveHash object

Installation

sudo gem install zilkey-active_hash

Or go to http://github.com/zilkey/active_hash/tree/master for more information.

Usage

To use ActiveHash, you need to:

Inherit from ActiveHash::Base
Define your fields
Define your data

A quick example would be:

class Country < ActiveHash::Base
  field :name
  self.data = [
    {:id => 1, :name => "US"},
    {:id => 2, :name => "Canada"}
  ]
end

Defining Fields

You can define fields in 2 ways, using the :fields method, or using the :field method, which allows you to specify a default value for the field:

class Country < ActiveHash::Base
  fields  :name, :population
  field   :is_axis_of_evil, :default => false
end

Defining Data

You can define data inside your class or outside. For example, you might have a class like this:

# app/models/country.rb
class Country < ActiveHash::Base
  fields  :name, :population
end

# config/initializers/data.rb
Country.data = [
    {:id => 1, :name => "US"},
    {:id => 2, :name => "Canada"}
]

If you prefer to store your data in YAML, see below.

Class Methods

ActiveHash gives you ActiveRecord-esque methods like:

Country.all             # => returns all Country objects
Country.count           # => returns the length of the .data array
Country.first           # => returns the first country object
Country.last            # => returns the last country object
Country.find 1          # => returns the first country object with that id
Country.find [1,2]      # => returns all Country objects with ids in the array
Country.find :all       # => same as .all
Country.find :all, args # => the second argument is totally ignored, but allows it to play nicely with AR
Country.find_by_id 1    # => find the first object that matches the id

It also gives you a few dynamic finder methods. For example, if you defined :name as a field, you’d get:

Country.find_by_name "foo"      # => returns the first object matching that name
Country.find_all_by_name "foo"  # => returns an array of the objects with matching names

Instance Methods

ActiveHash objects implement enough of the ActiveRecord api to satisfy most common needs. For example:

Country#id          # => returns the numeric id or nil
Country#quoted_id   # => returns the numeric id
Country#to_param    # => returns the id as a string
Country#new_record? # => false
Country#readonly?   # => true
Country#hash        # => the hash of the id (or the hash of nil)
Country#eql?        # => compares type and id, returns false if id is nil

ActiveHash also gives you methods related to the fields you defined. For example, if you defined :name as a field, you’d get:

Country#name        # => returns the passed in name
Country#name?       # => returns true if the name is not blank

Integration with Rails

You can create .belongs_to associations from rails objects, like so:

class Country < ActiveHash::Base
  fields  :name, :population
end

class Person < ActiveRecord::Base
  belongs_to :country
end

You can also use standard rails view helpers, like #collection_select:

<%= collection_select :person, :country_id, Country.all, :id, :name %>

ActiveYaml

If you want to store your data in YAML files, just inherit from ActiveYaml and specify your path information:

class Country < ActiveYaml::Base
  field :name
end

By default, this class will look for a yml file named “countries.yml” in the same directory as the file. You can either change the directory it looks in, the filename it looks for, or both:

class Country < ActiveYaml::Base
  set_root_path "/u/data"
  set_filename "sample"
  field :name
end

The above example will look for the file “/u/data/sample.yml”.

ActiveYaml, as well as ActiveFile, check the mtime of the file you specified, and reloads the data if the mtime has changed. So you can replace the data in the files even if your app is running in production mode in rails.

ActiveFile

If you store encrypted data, or you’d like to store your flat files as CSV or XML or any other format, you can easily extend ActiveHash to parse and load your file. Just add a custom ::load_file method, and define the extension you want the file to use:

class Country < ActiveFile::Base
  set_root_path "/u/data"
  set_filename "sample"
  field :name

  class << self
    def extension
      ".super_secret"
    end

    def load_file
      MyAwesomeDecoder.load_file(full_path)
    end
  end
end

The two methods you need to implement are load_file, which needs to return an array of hashes, and .extension, which returns the file extension you are using. You have full_path available to you if you wish, or you can provide your own path.

Authors

Written by Mike Dalessio, Ben Woosley and Jeff Dean

Enjoy!

Standup 07/21/2009: Rails 2.3.3 is out

Pivotal Labs

Tuesday, July 21, 2009

Interesting Things

Rails 2.3.3 was released yesterday. It is a minor point release but a notable new feature is a faster decoding backend for JSON.
The Evening with Palm webOS event is tonight at 6:30!
There is a new mailing list for the Jasmine Javascript testing framework.
Braid gotcha be careful when using Braid to checkout a specific branch of a Git repository. If you checkout a repository with Braid, and then later decide that you want to switch to a different branch (i.e. going from master to 2-3-stable with Rails) doing a braid remove vendor/rails is not sufficient! The reason is when you add a external with Braid it also adds a remote branch in your Git repository. If you re-add the external, the old remote will be reused, even if you specify a different branch. To avoid this, remove the remote in addition to removing the external. To view your remotes run git remote and remove a remote with git remove rm some/remote/name.

Weirdness with using serialized with Single Table Inheritance in Rails

If you have a class that uses a serialized categories attribute like this:

class Wibble < ActiveRecord::Base
  serialized :categories
end

You can do:

wibble = Wibble.create!(:categories => ['Restaurants', 'Bars'])
wibble.reload.categories #=> ['Restaurants', 'Bars']

We’ve experienced problems with this once we added single table inheritance (STI) to the Wibble class.

class Thingie < ActiveRecord::Base
end

class Wibble < Thingie
  serialized :categories
end

Now, sometimes reloading a Wibble would return the serialized string instead of the array:

wibble = Wibble.create!(:categories => ['Restaurants', 'Bars'])
wibble.reload.categories #=> "-- n- Restaurantsn- Barsn"

Our solution, while not ideal, was to move the serialized declaration to the STI superclass.

class Thingie < ActiveRecord::Base
  serialized :categories
end

Standup 07/20/2009: render_template bug in RSpec

Pivotal Labs

Monday, July 20, 2009

Interesting Things

Prior to RSpec 1.2.7, render_template in rspec-rails had a bug where render_template('new') would pass if ‘newer’ was rendered (or anything that started with ‘new’). Internally render_template was converting the string argument to a regular expression which was allowing ‘new’ to positively match ‘newer’ even though it was not an exact match. In RSpec-Rails 1.2.7 this bug has been fixed.

Sanitizing Solr requests

Pivotal Labs

Friday, July 17, 2009

If you’re accepting user input for Solr (which I expect most projects using it are), you’ve probably noticed that you need to sanitize what queries you pass to Solr. After reading a bunch of conflicting documentation and blog posts, I put together a simple little module to handle it for you. It should strip out everything that would cause Solr to throw an error on a query string. Let me know if it works for you or if I missed any corner cases!

module SolrStringSanitizer
  ILLEGAL_SOLR_CHARACTERS_REGEXP = /+|-|!|(|)|{|}|[|]|^||"|~|*|?|:|;|&&|||/

  def self.sanitize(string)
    if string
      string.gsub(ILLEGAL_SOLR_CHARACTERS_REGEXP,"")
    end
  end
end

Standup 7/17/2009: Mashery for API authentication, bunny gem for synchronous AMQP pub/sub

Justin Richard

Friday, July 17, 2009

Help

“What’s a good way to disable/enable features in an application? Sometimes our client needs to deploy, but not enable all the currently in progress features.”

It was recommended that you make branches in your source control manager for features and avoid global variables to use and switch on in your code.

“How are others authenticating requests to their API?”

One team uses Mashery to manage the public facing connection points to their API. Mashery manages the developer API keys, authentication, response caching and metrics. So far it’s worked well for them.

Interesting

bunny is a gem that does synchronous pub/sub to an AMQP server. It provides and exception on failure when the server is unavailable. The asynchronous amqp gem silently fails when the AMQP server is unavailable.