This tab tearing capability is a pretty neat feature - I know you can already do this in Safari, Opera and Galeon. It’s really well done in Safari, which I think is what Firefox is emulating. Nice to see Firefox follow suit!

If you can’t wait for Firefox 3.1, try it out in a recent Firefox nighty build (remember to use a new profile unless you are willing to risk corrupting your daily profile).

Here’s what you can do:

1. Go to about:config in Firefox.
2. Type in “session” in the “Filter” box.
3. Edit browser.sessionhistory.max_entries - this is the number of pages stored in the history of your browsing session. Basically these are pages that can be reached using your Back and Forward buttons. The default is 50 - I reduced it to 20.
4. Edit browser.sessionhistory.max_total_viewers - this is the number of pages that are stored in RAM so that they aren’t re-processed by Firefox’s rendering engine. This is what allows you to go Back to a page in Firefox and have it load almost instantaneously. The number of pages stored actually depends on the amount of RAM on your machine (see this). I reduced this to 4 (I have 2GB RAM).
5. Edit browser.sessionstore.max_tabs_undo - the number of tabs you can restore after closing them (you can do this with Ctrl/Cmd-Shift-T). The default of 10 is more than I really need, so I reduced it to 3 tabs.
6. Edit browser.sessionstore.interval - Firefox saves your session after every 10 seconds by default. I changed this to a more conservative 30000 milliseconds.

You can read more about these preferences and more at the MozillaZine Knowledge Base. If you’ve any tips on how to improve Firefox’s performance, be sure to share!

But we were attached to our ugly shade of green to leave those pages in their naked glory. Preliminary CSI work told me that some cached stylesheets generated by Rails were empty files. Why is this is happening?

stylesheet_link_tag and the :cache option

Was I overriding the stylesheets generated by Rails in different pages? Because we have a lot of cobranded sites and country sites on wego.com, I use the :cache option when using stylesheet_link_tag very often.

For example, the main wego.com site’s layout template has a stylesheet_link_tag like this (in reality there are a whole lot more stylesheets):

<%= stylesheet_link_tag 'yui/reset-fonts', 'search',  :cache => 'cache/search/listings' %>

When I need to make a new page for a cobranded site, I’ll create a new layout template with this:

<%= stylesheet_link_tag 'yui/reset-fonts', 'search', "sites/#{current_site}/cobrand", :cache => "cache/#{current_site}/search/listings" %>

Oftentimes I’d copy and paste (boo and hiss all you want!) the stylesheet_link_tag from one layout template to another and forget to update the cache path (the :cache => '/path/to/stylesheet' part). Two different stylesheet sets being cached to the same path is naturally a very stupid thing to do. So this wasn’t it, but it’s good to point this out because I have made this mistake at least 2 times!

Don’t check in generated CSS files by accident

Next, since I was using Sass, I was by now pretty sure that was it. First things first: did I check in a generated CSS file into source control (we use Git)? It’s another amateur mistake, but unsurprisingly, I’ve done this a couple of times. I think I’d wasted about an hour hunting down the reason for a style change that just wouldn’t show up. Yeah, I could have just added *.css to .gitignore, but I’m still using a mix of pure CSS and Sass templates.

The problem

In the end, I found this blog post by Ari Lerner on the CitrusByte blog about similar woes with Sass in production that set me on the path to a solution. It seems that when Rails encounters stylesheet_link_tag calls, it starts to pull together all the stylesheets and sometimes Sass is unable to generate the CSS files fast enough. Rails then throws an exception about not being able to find the CSS files and outputs an empty CSS file to the cache path.

The solution

The solution? Generate all the CSS files from Sass templates prior to restarting Rails when deploying. I added a rake task for updating all the Sass stylesheets:

namespace :sass do
  desc 'Updates stylesheets if necessary from their Sass templates.'
  task :update => :environment do
    Sass::Plugin.update_stylesheets
  end
end

Then, I created a mirror of this as a Capistrano task:

namespace :sass do
  desc 'Updates the stylesheets generated by Sass'
  task :update, :roles => :app do
    invoke_command "cd #{latest_release}; RAILS_ENV=#{rails_env} rake sass:update"
  end

  # Generate all the stylesheets manually (from their Sass templates) before each restart.
  before 'deploy:restart', 'sass:update'
end

Now, whenever I do a cap deploy, the stylesheets are generated before the Rails processes are restarted, ensuring that Rails’ stylesheet_link_tag helper is always able to find the pure CSS files when trying to merge them together and caching them to a single file.

Anyway, if you hold down the Cmd key (aka the Apple key), a menu pops up that shows the folder hierarchy of where the currently opened QuickTime movie is in your filesystem:

This works in all Mac apps that display the filename of the currently open/focused file in the titlebar.

It’s useful for me since my NADD means I try to close as many unused windows as possible to adhere to my Cmd-Tab diet - now I can close Finder windows after opening files and be sure that I can get back to them quickly. What about QuickSilver? Yup, I do use (and love) QuickSilver but I don’t let it catalog every single file!

Another nice thing about this is that I can easily reveal files in Finder in my favorite text editor (TextMate) without needing to use the project drawer:

Catch the new first edition - this one’s about the API changes since Rails 2.1.

Here’s a shot of Portland Convention Center where it’s all happening:

There’re queues for collection of badges after registering your attendance:

Patience in the queue rewarded me with a RailsConf badge/name tag:

I was at the Meta-programming Ruby for Fun & Profit tutorial in the morning. I think when I selected the tutorial it was before I’d seen Neal Ford and Patrick Farley’s (the speakers) presentation videos from elsewhere - I know Patrick presented at MWRC and enjoyed that video.

So anyway, after the break I went over to the Refactoring Your Rails Application tutorial. Was pretty good, but I didn’t learn much I didn’t already know.

Lunch came in the form of a pretty box:

After lunch was the 2nd tutorial session and I went to both CI for the Rails Guy (or Gal) (by Chad Woolley) and Developer Testing Tricks (by Brian Takita). There were some scathing comments about how the tutorials were rather underwhelming so far in #railsconf on IRC. While I agree that the tutorials were rather underwhelming, I think I should have expected it. Oh well, I’ll know to skip them next time.

Later that night, at the Birds of a Feather session, after stealing a Pivotal Labs t-shirt (they’re launching a bug tracker, project management type app called Pivotal Tracker at RailsConf), Yehuda Katz (Merb and jQuery ninja) gave a presentation on Merb (geared towards Rails folks). It was a pretty interesting talk though there wasn’t much above what Ezra had presented previously at GoRuCo 2008 and at MWRC 2008 (I think Yehuda did one too but I can’t remember where now). Yehuda pointed out a (heated) discussion that happened recently on keeping Merb syntax as Rails-friendly as possible. I have no objection against a different syntax really, especially since Merb looks pretty well-documented in the source itself - would be nice if someone could point out an up-to-date Merb tutorial though.

Anyway, that’s it from me - as always, if anyone who reads my blog recognizes me at RailsConf, do say hi (#railsconf works too).

I’ll be at (my first) Railsconf 2008 in Portland, Oregon this Thursday onwards - if anyone sees me and recognizes me from my Facebook picture please come and say hi (no head butting though).

This week’s report covers changes from 19th May 2008 to 25th May 2008 (the day the corresponding Rails Envy podcast was recorded).

first and last methods now work with associations and named_scope

Remember how the merging of the has_finder gem into Rails allowed you to do things like Post.first and Post.last?

Now you can go one step further and use the same methods on your ActiveRecord associations. For example:

post = Post.find(1)
first_comment = post.comments.first

If you have a named_scope named recent defined, you can even do this:

post.comments.recent.last

This neat little enhancement is courtesy of Ryan Bates (yes, that Ryan Bates of Railscasts fame).

Related changeset: http://github.com/rails/rails/commit/73c59638549686fccc749ffd3ac53cb533c5fd61

Cache stores now have an exist? method and controllers get fragment_exist?

The cache stores in Rails (Memcache, file stores, etc.) now have an exist? method that checks whether a cached value exists given a cache key. This allows Rails controllers to expose a fragment_exist?
method that allows you to check for existence of a cache fragment:

fragment_exist?('example.com/foo/bar')

This little enhancement is courtesy of José Valim.

Related changeset: http://github.com/rails/rails/commit/99860b72aebe0348f41e82d4710343498d89a84b#diff-2

Create association records with block argument

You can now create records for associations like so:

post.coments.create!(:title => 'Techcrunch') do |c|
  c.body = "Rails can't scale"
end

This is in keeping with the ActiveRecord::Base.create change previously mentioned.

Credit for this patch goes (once again) to Ryan Bates.

Related changeset: http://github.com/rails/rails/commit/6cba97d2a449faf21aec9fe9d4434067e414226f

As always, let me know of any suggestions or how I can improve the Living on the Edge (of Rails) series.

This week’s report covers changes from 12th May 2008 to 18th May 2008 (the day the corresponding Rails Envy podcast was recorded).

caches_action can has conditionals

caches_action now takes an :if option (just like caches_page does). For example:

caches_action :index, :if => Proc.new { |c| !c.request.format.json? }

This little enhancement is courtesy of José Valim.

Related changeset: http://github.com/rails/rails/commit/7708650f73ddb4db300ea2059c60c1d907a4384e

Bugfix: :select option is now scanned in ActiveRecord finders to ensure needed tables are included in generated SQL

Post.find(:all, :include => :author, :select => 'posts.*, authors.id as "author_id"', :limit => 2)

Would generate an SQL statement like this:

SELECT posts.*, authors.id as "author_id" FROM "posts" LIMIT 2

Notice how the authors table is not joined. This oversight is now fixed.

Thanks go to John Devine for this bugfix.

Related changeset: http://github.com/rails/rails/commit/b28b54cab090bed8f099ef375b419a8f92390dd4

As always, let me know of any suggestions or how I can improve the Living on the Edge (of Rails) series. Also, if anyone has any recommendations of (non-ruby-related) things to do in Portland, do let me know!

• You can specify the user you want to use to login to your gateway server like so: set :gateway, 'deploy@deploy.example.com'. This logs in to your gateway server as the “deploy” user.
• You can specify an alternate SSH port for both your gateway and your deployment servers. E.g. setting ssh_options[:port] = 11111 will make Capistrano SSH to your gateway server with on port 11111. For your actual application (and web and database) servers, you can specify the SSH port like so:

  set :gateway, 'deploy@deploy.example.com'
  role :app, '192.168.1.113:22222'
  role :web, '192.168.1.113:22222'
  role :db,  '192.168.1.113:22222', :primary => true

• If you’re using public key authentication, you should put the public keys of your users (those who be deploying your app) on the gateway server and on the actual servers. I thought Capistrano would use the key of the “deploy” user but nope.

script/dbconsole

A script/dbconsole script has been added that allows you to connect to your database using its console client.

If you needed to connect to your production MySQL database (you better know what you are doing!), for example, you can run RAILS_ENV=production script/dbconsole or simply script/dbconsole production (thanks to Ryan Bates for pointing this out!) and it will login to your database server using the command line MySQL client. This also works with the PostgreSQL and SQLite databases.

To use this script in your Rails app, remember to run rake rails:update:scripts after updating to edge Rails.

This nice little enhancement courtesy of Steve Purcell, who originally had a similar database console plugin.

Related changeset: http://github.com/rails/rails/commit/4a07103687084496b773e18a03b1f2f5e686f7ad

flash.now is now accessible in tests

This is something that many of us Rails developers have probably come across when writing tests for flash messages being set with flash.now, myself included. Basically, you couldn’t test the contents of your flash.now because they were always being emptied before your test could get to them.

# In your controller:
flash.now[:notice] = 'You gotta be kidding me!'

# In your test:
assert_equal 'You gotta be kidding me!', flash.now[:notice]
# FAILS because flash.now[:notice] is nil

Andreas Neuhaus took a good look at how it works and figured out how to make testing flash.now work without resorting to assert_selects.

Related changeset: http://github.com/rails/rails/commit/74eed6290e63111d1aad2b181692a84f4f040aea

There isn’t much else of note so far but if you’d like to know every gritty detail, you’d probably want to peruse the Rails commit logs. As always, let me know of any suggestions or how I can improve the Living on the Edge (of Rails) series.

change_table for ActiveRecord migrations

Thanks to Jeff Dean, who also blogged about the new change_table feature in ActiveRecord migrations, you can now change a table with a block like so:

change_table :videos do |t|
  t.add_timestamps
  t.add_belongs_to :goat
  t.add_string :name, :email, :limit => 20
  t.remove_column :name, :email # takes multiple arguments
  t.rename :new_name
  t.string :new_string_column # executes against the renamed table name
end

Some key things to note:

• add_XXX would add a new column for you, e.g. add_string would add a new string field.
• Of course, add_timestamps would add the magic created_at and updated_at datetime fields.
• remove_column now takes multiple arguments.
• rename would rename the table.

Very nice, DRY enhancement, props to Jeff Dean once again.

Related changeset: http://github.com/rails/rails/commit/96980bd561d79824b6cb6efbcbecdcbf8785d452

ActiveRecord::Base.create takes a block like ActiveRecord::Base.new

Yup now you can also create ActiveRecord objects with a block argument just like you could for ActiveRecord::Base.new:

@person = Person.create(params[:person]) do |p|
  p.name = 'Konata Izumi'
  p.age = 17
end

Credit goes to Adam Meehan for this patch.

Related changeset: http://github.com/rails/rails/commit/dd120ede53eaf71dee76894998a81626b7a689fc

Bugfix: change_column should be able to use :null => true on a field that
formerly had false

You can now use change_column in your migrations to alter a column as nullable if it was previously NOT NULL.

This bugfix is courtesy of Nate Wiger.

Related changeset: http://github.com/rails/rails/commit/10ef65a3b054270ed3d458ec8eb7c2b9a3e638f7

As always, let me know of any suggestions or how I can improve the Living on the Edge (of Rails) series.

So yes, the new site: http://www.wego.com/.

We’ve decided to push it “live” as a beta product (and we know it is very much in beta, we’re not kidding or trying to be Web 2.0-ish) prior to our launch party next week. Give it a few hits or so and let me know of any feedback (leaving a comment here is good), especially what annoys you. You might even want to use it to search for airline tickets or to book hotel rooms for your next trip and let us know if we managed to somehow epic fail at the task. If you liked it or booked a trip somewhere, we’re glad to have helped you on your way.

I’d write more about wego.com but what I really wanted to focus on, being a Rubyist and all, is what is really cool to me about wego.com - we’ve rebuilt our Hotels product from the ground up (it was a mostly Java before, and it is still live on http://bezurk.com/hotels/) in 85% Ruby, 8% JavaScript, 5% Erlang, and 2% Java. Well, those are rough figures anyway. We also made a strong effort to keep our mostly AJAX application as usable as possible without JavaScript but I’ll admit, we had to cut some corners due to deadlines.

I’d love to be more specific about the design and architecture of our Hotels application and on the cool stuff (CouchDB, Rack, Solr, jQuery, libmemcached, and of course, Ruby) we’ve used that have made our lives as developers much easier than when we were in Javaland - but I’d leave that for a later post. I’m sure my friend Arun Thampi also has a war story to tell so we’ll come up with something entertaining. Stay tuned!

Not much interesting to report this week - there were mostly a bunch of bugfixes and Ruby 1.8.7-compatibility commits.

Introduce ActiveResource::Base.timeout and rescuing from Timeout::Error in ActiveResource::Connection

These are 2 changes that I’d talked about earlier this week so I won’t repeat myself - take a read through ActiveResource timeouts and why it matters.

Smart integer datatype for the MySQL adapter in migrations

The MySQL adapter in Rails now maps the integer column type in your migrations to either smallint, int, or bigint depending on the :limit option.

This means that a migration like this:

def self.up
  create_table :searches do |t|
    t.integer :foo, :limit => 2
  end

will create your foo column as a smallint(2) MySQL datatype (instead of int(2) before). (More information MySQL numeric datatypes.)

Credit goes to DHH for this patch.

Related changeset: http://github.com/rails/rails/commit/a37546517dad9f6d9a7de6e1dba4d960909d71e8

As always, let me know of any suggestions or how I can improve the Living on the Edge (of Rails) series.