Why did Heroku stop precompiling my assets?

I come into work today to this error:

ActionView::Template::Error ('twitter/bootstrap/bootstrap.less' wasn't found.

Odd...It works in development. What could have happened?

The search

I ran the application locally with the development environment and got the same error. Great, at least it's reproducible. Let's hit the Googles...

Hmm, some mentions in twitter-bootstrap-rails and some scattered StackOverflow questions, but nothing that works. Then I noticed Heroku was no longer precompiling the assets on deploy.

The discovery

The Heroku docs have this glorious quote:

The most common cause of failures in assets:precompile is an app that relies on having its environment present to boot. Your app's config vars are not present in the environment during slug compilation, so you should take steps to handle the nil case for config vars (and add-on resources) in your initializers.

A recent change added some configuration variables in application.rb that referenced some environment variables.

The fix

Based on some more documentation and community help, I moved the configuration into an initializer that is loaded after the slug compilation when it can access the environment variables.

Deploy. Working. #winning.

Using ActiveSupport::TimeWithZone without Rails

My fast spec test suite does not load Rails (otherwise it's not so fast, right?), but I want to use the niceness of ActiveSupport::TimeWithZone to create a DateRange class like so:

class DateRange
  class DateRangeError < StandardError; end

  def initialize(range)
    @range = range
    raise_if_not_utc
  end

  def start_date
    range.first.beginning_of_day
  end

  def end_date
    range.last.end_of_day
  end

  private

  attr_reader :range

  def raise_if_not_utc
    if start_date.zone != 'UTC' || end_date.zone != 'UTC'
      raise DateRangeError.new('The date ranges must be in UTC.')
    end
  end
end

The corresponding tests didn't like Time.zone - they thought it was nil. Which it is.

The Fix

The tests need the proper ActiveSupport module loaded, and the time zone needs to be set.

require 'active_support/core_ext'
Time.zone = 'UTC'

Now the time zone is set and the tests will work as expected.

let(:range) { daterange.new(10.days.ago..time.zone.now) }

describe '#start_date' do
  it 'gets the beginning of the day for the earliest date in the range' do
    expect(range.start_date.to_i).to eq(Time.zone.parse('1999-12-31 00:00:00').to_i)
  end

  it 'is in UTC' do
    expect(range.start_date.zone).to eq('UTC')
  end
end

Rails controller tests without Rails

In our continued path to faster tests, we've tried doing controller tests without loading Rails and using only what's minimally required to fully test the functionality. the idea is that not only will the tests be faster, but they will drive the controller's design to be thinner.

How did it work out? First the background.

We implemented a controller that received an OAuth callback from another site to allow their users to directly login to Crowdcast. The required code was minimal, so we tried to test minimally as well.

Since we're not loading Rails, we need to manually load some required libraries for the controller. We need enough to load the controller and its dependencies (in this case, a url generator class and the controller itself) successfully.

require 'uri'
require 'active_support'
require 'fast_spec/spec_helper'
require 'lib/crowdcast/url_generator'
require 'app/controllers/oauth_controller'

We also need to stub out calls to models, both ActiveRecord and plain old Ruby objects the controller uses. Here is where we realize how many of these we need and use the pain of stubbing yet another class to drive the design to remove that dependency.

stub_class 'UserSession'
stub_active_record_model 'Site'
stub_active_record_model 'SalesforceConnection'

Some are necessary, such as those for Authlogic and the relevant AR classes we're calling, but we were able to move calls to others out of the controller to make the tests easier to write and the code easier to read and maintain. All the usual good stuff we get from TDD and OOP.

Here's an example:

describe OauthController do
  let(:controller) { OauthController.new }

  describe "#callback" do
    let(:user_attributes) {{ :email => "email" }}
    let(:user) { stub("user", :single_access_token => "foo") }
    let(:site) { stub("site") }
    let(:redirect_to_url) { "https://foo.example.com:8080?foo=bar&baz=quux" }
    let(:state) { CGI.escape({:url => redirect_to_url, :subdomain => "foo" }.to_json) }

  before do
    controller.stub(:params) {{ :code => "foo", :state => state }}
    controller.stub(:current_user) { user }
    controller.stub(:session) {{ :return_to => "/return_path" }}
    Crowdcast::Config.stub(:salesforce) {{ :id => "bar" }}

    Salesforce::UserResolver.stub(:user_attributes_by_auth_code).with({ :id => "bar" }, "foo").and_return(user_attributes)
    SalesforceConnection.stub(:connect).and_return(user)
    Site.stub(:find_by_subdomain).with("foo").and_return(site)
  end

  it "creates a SalesforceConnection connection" do
    SalesforceConnection.should_receive(:connect).once.with(user, user_attributes)
    controller.callback
  end

  it "redirects to the return_to path with user's single access token" do
    controller.should_receive(:redirect_to).with(redirect_to_url + "&token=foo")
    controller.callback
  end
end

You can see that we need a fair amount of initial setup to get both the regular methods all controllers access and the specific ones we want to test or stub in the specific tests. It's still feels reasonable considering that we lose the Rails loading overhead and tests are incredibly fast.

Here is the controller:

def callback
  if params[:code]
    cc_user = connect_user_to_salesforce
    redirect_to Crowdcast::UrlGenerator.url(:url => return_to_url_from_callback, :params => { :token => cc_user.single_access_token })
  else
    flash[:error] = params[:error_description] if params[:error_description]
    redirect_to return_to_url_from_callback
  end
end

private

def connect_user_to_salesforce
  SalesforceConnection.connect(existing_or_autoregistered_user)
end

def existing_or_autoregistered_user
  current_user || Salesforce::UserAutoRegistrar.register(current_site)
end

def return_to_url_from_callback
  state_from_callback["url"]
end

def state_from_callback
  JSON.parse(CGI.unescape(params[:state]))
end

And now a problem.

We want to add some more Rails controller goodness in case there are exceptions (they're always where you least expect them). Check this out.

rescue_from Salesforce::UserResolver::UnsupportedAccountTypeError, :with => :account_error
rescue_from Salesforce::TokenResolver::AuthCodeExpiredError, :with => :expired_auth_code

def account_error
  render :status => :precondition_failed, :action => "account_error", :layout => "not_found"
end

Now we need to figure out how to get rescue_from or have more stubbing on the controller class. Before, when our controller was very lightweight, we could deal with the minimal amount of manual dependencies to get the speed increases. But at this point we decided to convert the controller to our "slow specs" folder, ie, our regular /spec folder, since the pain of managing the external dependencies reached a threshold we weren't willing to cross.

How did we decide this was the time? It wasn't anything specific but the overall feel of the code getting too complicated and stub-happy; we weren't getting pain from bad design but from using a framework.

Conclusions

Testing without Rails is still new, and we're still learning what works and what doesn't. Should we automatically test functionality that's coupled to the framework within the framework? I still say no, that we can get out of the framework if we use only a minimal subset that we can maintain manually. We decided to return to loading Rails when that subset was no longer minimal. That situation did not come up for some time, and it isn't a foregone conclusion that it always will. It's a developer's decision on the tradeoffs. Plus it was a great learning experience.

Don't be lazy with route resources and allow unused ones

Refactoring controllers to make then skinny is usually a multi-step affair. The common process is to get current functionality tested and them refactor the business logic where it needs to go, moving the tests along with them to their corresponding test files. As the code is moved (to models or service objects, etc.), we can stub out those calls in the controller. Eventually, hopefully, the controller actions will be only a few assignments and a render call. Since the effects can reach across the entire Rails architecture (the M, V, and C, if you will), I find smoke testing often a necessary step in the process.

Which brings me to two sources of frustration: the default Rails (2.0) routes and default restful routes.

map.connect ':controller/:action/:id.:format'

This is just ripe for annoyance. Having a list of all the routes set up and not being able to find the one that I need? This guys fault. Rails has a lot of magic, but this has become a major pain because of the implicit and non-obvious nature of allowing anything one wants to sit next to a specified list. But then again, that specific list can have problems of its own too.

map.resources :photos

This can be fantastic. One line gives us so much power and ease: 7 actions for the price of one. What's the problem? Well, when I was recently working on some tech debt, I thought I found some unused actions. But how did I know for sure? I had to do a lot of grepping and manual testing to make sure these really weren't used. It turned out that one I thought wasn't was actually called in one specific case, so I had to back out my changes.

This would have been less painful if the code coverage was better, but that's sometimes the nature of old code, isn't it? If there are methods in the controller that aren't used, it's one thing to not have them declared, but what happens when there is code for an action that goes unused? I decided to be explicit about which routes to use so I didn't have to deal with the same problems later on (I can be my own worst enemy sometimes).

Let's lock down those resources:

map.resources :foobars, :only => [ :index, :show, :new, :create ]

If we're not using :edit, :update, and :destroy, let's not clutter things up with implications.

Maybe it's overkill, but tech debt can be painful to pay back, and I don't want to piss off my future self if this were to happen again.

State Machine Transactions

The Setup

We have a model that has a state machine on it to activate, close, and cancel after meeting certain conditions. When closing this model, we want to manipulate an associated model as well, and we want these in a transaction to preserve data integrity. Unfortunately, there is logic in the associated model that doesn't like to have the original model in the new state before saving. The obvious solution is to set up the following callbacks:

state :closed, :enter => :enter_close, :after => :after_close

def enter_closed
  # do stuff to model
end

def after_close
  # do stuff to associated model
end

The Problem

It turns out that the callbacks are not wrapped in a transaction and that #after_close is called after the model saves, leaving the associated model in danger of getting in a back state or failing validations.

The Solution

Using this post as a guide, we ended up with this code:

class ActiveRecord::Base
  def self.transaction_around_transitions
    event_table.keys.each do |t|
      define_method("#{t}_with_lock!") do
        transaction do
          send("#{t}_without_lock!")
        end
      end
      alias_method_chain "#{t}!", :lock
    end
  end
end

And call that method after setting up the transitions:

event :close do
  transitions :from => :foo, :to => :bar
end

# other transitions...

transaction_around_transitions

Now there is a transaction around the entire state change and its callbacks, and we'll be able to sleep tonight knowing that all the saving is safe and sound, all wrapped up in a nice, warm transaction.

Rails 2.3.5 Bug With accepts_nested_attributes_for

The Setup

At work, our application has a series of questions it asks users, and an administrator can set a target of what he thinks (or wants) the answer to be.

class Question < ActiveRecord::Base
  has_many :targets
  accepts_nested_attributes_for :targets, :allow_destroy => true
end

class Target < ActiveRecord::Base
  belongs_to :question
end

The administrator fills the form out, choosing a target or not, and Rails will save, update, or destroy it as normal. Well, almost. Apparently there is a bug in Rails 2.3.5 that will save the child model twice, and we're experiencing that now.

What I Want To Do

Upgrade to Rails 3.1, get all the new hotness and bug fixes, and not worry about this problem.

What I'm Going To Do

Since we don't have the resources to upgrade Rails (yet...), we need a workaround. Here's what we came up with.

after_save :ensure_one_target_while_in_draft

def ensure_one_target_while_in_draft
  if draft? && targets.count > 1
    targets[1..-1].each { |t| t.destroy }
  end
end

This problem only comes up when a question has not been activated and is still in draft mode. Once it's activated, the administrator cannot change the target but only add additional ones. So while in that state, and if there are multiple targets, destroy all but the first. This needs to be in an after_save callback because the double-save does not happen until after the question is saved. It's not elegant, but it works. I don't want to try to patch Rails and remember to deal with that later when we finally do upgrade, and the situation is isolated enough that there isn't a performance hit and it's easy to remove once it's no longer necessary. Elegant? No. But it's a bug fix for the framework, it's well documented in the code, and it works.

Rails Security Refactor: Protect Those Attributes!

Rails in the enterprise is still a fairly new concept, but the same web development principles we have also exist in this new realm. One no-brainer is security, and one no-brainer part of security is protecting data from malicious user input.

The basic Rails ways to protect attributes on a model are attr_protected and attr_accessible. If neither are set, it's easy to imagine a situation where a user updates his attributes and the corresponding model has a boolean admin field on it. The user can trivially submit post data that looks like this:

params: { "user" => { :email => "foo@bar.com", :first_name => "Joe", :last_name => "Hacker", :admin => "true" } }

Oops! Now Mr. Hacker is Mr. Admin!

So how do we get from here to (more) secure? Throwing attr_accessible on the model to whitelist is the safest, but it can cause a lot of unknown breakage if there aren't tests around the fields, which there probably aren't because why would someone test the fields for accessibility if they are automatically accessible? An interim step is to create a blacklist using attr_protected to only protect specified fields, get tests around these protected fields, and then upgrade to attr_accessible.

For our user model, let's protect that admin field:

Class User < ActiveRecord::Base
  attr_protected :admin
end

And the tests:

describe User do
  describe "with protected fields" do
    context "including admin" do
      let(:user) { Factory.build(:user, :admin => false) }

      it "cannot mass-update" do
        user.update_attributes({ :admin => true })
        user.admin.should be_false
      end
    end
  end  
end

We instantiate a user object with admin set to false, try to update that field, and ensure that it did not get updated. If we use user.update_attribute(:admin, true), the test would fail because that skips all the ActiveRecord protection, so we use user.update_attributes(). Doing this for all the fields we want to protect will eventually get us to the point where we can swap out attr_protected with the easier-to-deal-with attr_accessible. Since we need to be explicit with attr_protected, it can get to be difficult to maintain quickly since we need to remember to add each new field we want to protect to the list and test it.

Class User < ActiveRecord::Base
  # attr_protected :id, :admin, :awesomeness_rating, :money
  attr_accessible :email, :first_name, :last_name
end

That's better. Tests and iterative development to the rescue!

Testing controller JSON responses in Rspec

I was recently rewriting some controller specs because they were way too heavy: all the models were saved to the database and there was no mocking. While trying to test the JSON response of an action, I got the following exception:

ActiveSupport::JSON::Encoding::CircularReferenceError

Here is the relevant controller code:

format.json do
  render :json => as_json(@questions)
end

Here is the test's mock:

question = mock_model(Question)

A little cryptic, right? After a little digging, I changed the mock to this:

question = mock_model(Question, :as_json => {'foo' => 'bar'})

Ah, there we go!

The spec ended up looking like this:

context "as json" do
  it "lists the questions" do
    question = mock_model(Question, :as_json => {'foo' => 'bar'})
    Question.should_receive(:find_ordered_subjects).and_return([question])
    get :index, :format => 'json'
    response.body.should == "[{\"foo\":\"bar\"}]"
  end
end

In our application_controller.rb, an as_json() method called to_json, which would call as_json in the test, resulting in a circular reference. Oops.

Don't forget to stub as_json()!

Emailing with Delayed Job

We used Delayed Job to queue emails sent out to users, both to offload that blocking process and for scheduling. It has worked well so far, but recently there were some strange bugs popping up. Some emails were stuck in the queue, and the error message was about bad YAML syntax.

Delayed Job serialized objects in its handler field, and, with some user input that's not encoded properly, created incorrect YAML. For example, this could happen:

id: 1
  foo: 'here is some 'text'
  bar: 'something else'

Notice the odd number of single quotes in foo? Yeah, that's bad. Since we already had that kind of data saved, we needed another way to fix this.

Instead of having methods in the notifier.rb file like so:

def forgot_password(user)
  ...
end

We did it like this:

def forgot_password(user_id)
  user = User.find(user_id)
  ...
end

Delayed Job serialized just the user id and not the entire user object, so any potentially harmful data wasn't saved. This was more expensive since the objects had to get instantiated again, but sending out email wasn't expensive for our app, so this solution worked well.

If you ever get strange YAML syntax errors from delayed job, perhaps this method will work for you.

Adding Field Separation for List Data

A Big List

MetalDetectr is effectively a list of data as specific as a user wishes to see. It will show only a list of releases a user has in his last.fm library to a list of everything on metal-archives.com. A big concern is presenting it properly, and one method is to delineate releases by whatever sort method a user wants to see. This can be by release date, by the band's name, by the release's name, or by the release's format (eg, EP, full-length, DVD).

The Algorithm

• Start with a table row showing the earliest or most recent, depending on sort order, of the selected sort column.
• Loop through the releases.
• If the current release's relevant field is greater/less than the preceding one, show another table row with the current release's field value.
• Show the release.

For example, the default sort is by US release date starting at the earliest date (and the current month so there's less noise). The list will display the current month and every album released during that month. When a release is next month, it will show next month and then all releases from that month. Continue on through the rest of the releases. If the user wants to see the list in descending order, it will show the last month first and work its way to the most current month.

The Code

First find the first value and display it in a full column span table row:

# views/releases/index,html.haml
- comparison_value = @releases.first.chain_methods(Release::FIELDS_WITH_METHODS[Release.default_sort(params[:s])])
= separator_row(comparison_value)

These two lines use the following methods:

# models/release.rb
# Sets the sort order to what's passed or us_date.
def self.default_sort(sort)
  sort || 'us_date'
end

# models/release.rb
# Takes an array of symbols and calls them on the release instance if it
# responds to them.
# Example: release.chain_methods([:us_date, :month]) => release.us_date.month
def chain_methods(methods)
  methods.inject(nil) do |memo, acc|
    target = memo ? memo : self
    target.respond_to?(acc) ? target.send(acc) : memo
  end
end

# helpers/releases_helper.rb
# Creates a row with a full colspan for the value.
def separator_row(value)
  value = Date::MONTHNAMES[value] if value.is_a?(Fixnum)
  content_tag(:tr, :class => cycle('even', 'odd')) do
    content_tag(:td, value, :class => 'separator_row', :colspan => 7)
  end
end

FIELDS_WITH_METHODS is a constant that contains a mapping of field names and methods to call on them to display properly:

# models/release.rb
FIELDS_WITH_METHODS = {
  'band' => [:band, :first, :downcase],
  'name' => [:name, :first, :downcase],
  'us_date' => [:us_date, :month],
  'euro_date' => [:euro_date, :month],
  'format' => [:format],
  nil => [:us_date, :month]
}

Then we loop through each release, updating the comparison value when we get to the next one:

# views/releases/index,html.haml
- @releases.each do |release|
  - current_value = release.chain_methods(Release::FIELDS_WITH_METHODS[Release.default_sort(params[:s])])
  - if Release.values_compared?(current_value, comparison_value, params[:d])
    - comparison_value = current_value
    = separator_row(comparison_value)
  - else
    - comparison_value = current_value
  = render release

Compare the two values based on the sort order:

# models/release.rb
# Sets the comparison operator to be greater than if the direction is nil or ascending,
# or less than if the direction is descending.
def self.comparison_operator(direction)
  (direction.nil? || direction == 'asc') ? :> : :<
end

# models/release.rb
# True if both value and comparison exist and
# if the direction is ascending:
#   true if value > comparison, false otherwise
# if the direction is descending:
#   true if value < comparison, false otherwise
def self.values_compared?(value, comparison, direction)
  value &&
  comparison &&
  value.send(
    Release.comparison_operator(direction),
    comparison
  )
end

We tried to abstract the comparisons and what's displayed so we can add new fields and only need to update the field-method mapping. There is always the possibility that a field is nil, since we don't always get all the possible data for every release, so chain_methods will call all the methods it can on a release instance until it finishes or returns nil. We could have chained a bunch of try()s together, but that didn't look right.

We also tried to get as much code out of the view as we could, and it can be improved, but it's okay for now.

Namespacing /lib Files and RSpec

I've been in an ongoing battle with RSpec to get it to properly load files in the /lib directory of a rails app. There's a class MetalArchivesFetcher wrapped in a MetalDetectr module as a namespace:

module MetalDetectr
  class MetalArchivesFetcher
    ...
  end
end

The spec file starts like this:

require 'spec_helper'
require 'metal_archives_fetcher'

describe MetalDetectr::MetalArchivesFetcher do
  ...
end

Without the require, I would receive the message, load_missing_constant': Expected /Users/danny/code/metaldetectr/lib/metal_archives_fetcher.rb to define MetalArchivesFetcher (LoadError) It felt a little off to need to require the file again because Rails already loads it in with config.autoload_paths += Dir["#{config.root}/lib/**/"] set in the config/application.rb file. I could put the require in spec_helper.rb, but it still felt strange.

I decided to remove the module namespace. That lets me remove the require line and all preceding MetalDetectr:: for every MetalArchivesFetcher call in the spec. Is this the right decision? It's definitely DRYer, but I do create tighter coupling. Jim Weirich's talk, "The Building Blocks of Modularity" (that I can't find online) does go over the trade-offs of writing code that is either more tightly or loosely coupled, and my takeaway from that is, since this file is already coupled to the application and models within it, why add an additional layer? It's more of a perceived loosening while only adding a bit more complexity. And that's usually not a good thing.

Perhaps I'll add it back in later, but for now, I'm not going to need it.

Metal Archives' JSON Results Parsing

Some further explanation of how to get Metal Archives' JSON data from a recent post is necessary. Through reading the markup and trial-and-error, I found the URL to receive the data I needed. Here it is:

http://www.metal-archives.com/search/ajax-advanced/searching/albums \
/?&releaseYearFrom=2011&releaseMonthFrom=1&releaseYearTo=2011 \
&releaseMonthTo=12&_=1&sEcho=0&iColumns=4&sColumns=&iDisplayStart=1& \
iDisplayLength=100&sNames=%2C%2C%2C

This returns a result set that looks like this:

{ 
 "error": "",
 "iTotalRecords": 3637,
 "iTotalDisplayRecords": 3637,
 "sEcho": 0,
 "aaData": [
  [ 
    "<a href=\"http://www.metal-archives.com/bands/037/3540277845\" title=\"037 (ES)\">037</a>",
    "<a href=\"http://www.metal-archives.com/albums/037/Los_Fuertes_Sobreviven/307703\">Los Fuertes Sobreviven</a>",
    "Full-length", 
    "May 24th, 2011 <!-- 2011-05-24 -->"  
 ],
  [ 
    "<a href=\"http://www.metal-archives.com/bands/037/3540277845\" title=\"037 (ES)\">037</a>",
    "<a href=\"http://www.metal-archives.com/albums/037/Tantas_Vidas/306172\">Tantas Vidas</a>",
    "Single", 
    "May 6th, 2011 <!-- 2011-05-06 -->"  
 ]

You'll notice the iTotalRecords field which conveniently provides the total amount to releases available. You'll also notice the the iDisplayStart parameter in the URL that lets us step through the results 100 at a time. By looping through (iTotalRecords / 100 + 1) times, incrementing iDispalyStart by i * 100, we can get a result set for all the records very quickly.

Now that we have the results, we just need a little regular expression magic to pull out all the information.

BAND_NAME_AND_COUNTRY_REGEXP = /(.+)\s{1}\(([a-zA-Z]{2})\)/
ALBUM_URL_AND_NAME_REGEXP = /"(.+)">(.+)<\/a>/
RELEASE_DATE_REGEXP = /<!--\s(.{10})\s-->/

There was a strange situation where an album didn't have a band page but displayed a message that the band didn't exist, so there is one last regular expression used to guard against a slightly alternative format for the data:

NO_BAND_REGEXP = /span.+<\/span/

The data are much easier to gather and never time-out now, so I was able to get rid of all the intermediate saving steps such as after gathering the paginated links and saving the last release searched when the site times-out. I'll probably have to add it back in to get the record label of the release since you'll notice it's absent in the JSON but it is available on the release's page.

The code to save the albums now looks like this:

agent = ::MetalArchives::Agent.new
agent.paginated_albums.each_with_index do |album_page, index|
  album_page.each do |album|
    if album[0].match(::MetalArchives::Agent::NO_BAND_REGEXP).nil?
      Release.create(
        :name => agent.album_name(album),
        :band => agent.band_name(album),
        :format => agent.release_type(album),
        :url => agent.album_url(album),
        :country => agent.country(album),
        :us_date => agent.release_date(album)
      )
    end
    CompletedStep.find_or_create_by_step(CompletedStep::ReleasesCollected)
  end
end

Quick and simple.

Introducing MetalDetectr

It came from a blog post. In July 2010, Cosmo Lee, creator of the metal blog Invisible Oranges requested "a simple list" of upcoming releases from metal-archives.com. I thought that this would be the perfect opportunity to:

1. Create something of value for a community I belong to
2. Help someone I genuinely appreciated for his hard work within the same community
3. Create a Rails 3 application and use some new technologies
4. Show off a little code on Github
5. Have fun!

Thus, Metaldetectr. This application will search metal-archives.com, the canonical site for all things metal, for upcoming releases and create a list with basic information for each release. The method is to programmatically search through the current year, returning a paginated list of results. By accessing each page of this list, we generate another list of possible releases. Going through that list and only choosing those releases that are in the future, we come up with the final list as requested. However, there are a few interesting problems that arose through the development process.

The first is that metal-archives.com times out. A lot. Each step in the above process needs to be able to save the spot it is on when the site is no longer accessible. If we're searching through the paginated list of results and it fails, we need to note which page we're on and continue from there the next time. The same with the links to each album.

Another problem is that metal-archives.com has human input, so there are human errors. Not every album has a specified release date, some only a month, some albums are in different languages that aren't easy to parse, and some have crazy titles or band names and can be almost impossible to automatically figure out exactly what each one of those is supposed to be. There will always need to be a manual step to clean up some data, but the main functionality is there.

To get better data, we pass each album through Amazon's US site and a few European sites (.uk, .de, and .fr currently) to check if the release date is different. Since Amazon actually provides the albums instead of just listing them, their release dates take highest priority.

I hope this ends up providing some value to the metal community. I constantly read about the desire for a one-stop list of upcoming releases, and I would like MetalDetectr to be that list.

You can look at the code yourself on my github account.

Testing content_tag in Rails 2.3.5 with RSpec

I'm working on a codebase that's still on Rails 2.3.5, and recently I added a group of radio buttons for users to estimate their expertise level when answering a question. I wanted to play with content_tag() more than I have, so here is the view helper:

module AnswersHelper
  # Creates the markup for displaying the expertise choices for an answer.
  def expertise_choices(answer)
    content_tag(:div, :id => 'choices') do
      content_tag(:span, :class => 'clarification') { 'Not at all' } +
      collect_expertise_choices(answer) +
      content_tag(:span, :class => 'clarification') { 'Very Much So' }
    end
  end

  private

  # Creates 5 radio buttons and selects the one with the value of the answer's
  # expertise value if it exists.
  def collect_expertise_choices(answer)
    (1..5).collect do |i|
      checked = (i == answer.expertise) ? { :checked => 'checked' } : {}
      radio_button('answer', 'expertise', i, checked)
    end.to_s
  end
end

Nothing difficult to get through, but some small notes of interest:

content_tag() can nest within other content_tag() calls, and you can append markup to each other to get everything you need to display properly. Also, don't forget to call to_s() to get a string, not an array, of the radio buttons.

Here is the partial that calls the helper:

#expertise
  Are you an expert on this topic?
  %br
  #choices
    %span.clarification Not at all
    = expertise_choices(answer)
    %span.clarification Very Much So

Finally, here are the accompanying tests:

require 'spec_helper'
include AnswersHelper

describe AnswersHelper do
  describe "#expertise_choices" do
    it "should display five radio buttons" do
      answer = mock_model(Answer, :expertise => nil)
      results = expertise_choices(answer)
      (1..5).each do |i|
        results.should have_tag('input', :id => "answer_expertise_#{i}", :type => 'radio', :value => i)
      end
    end

    it "should have a #choices div" do
      answer = mock_model(Answer, :expertise => nil)
      results = expertise_choices(answer)
      results.should have_tag('div#choices')
    end

    it "should have two .clarification spans" do
      answer = mock_model(Answer, :expertise => nil)
      results = expertise_choices(answer)
      results.should have_tag('span.clarification', :minimum => 2)
    end

    context "when editing" do
      it "should check the existing choice" do
        answer = mock_model(Answer, :expertise => 4)
        results = expertise_choices(answer)
        results.should have_tag('input[checked="checked"]', :type => 'radio', :value => 4)
      end
    end
  end
end

Again, nothing difficult to understand, but you can see how cool and powerful have_tag() is. Unfortunately, when we upgrade to RSpec 2, we'll need to change these tests to use webrat's have_selector(). But for now, let's just enjoy the time we have together, okay?