Rails helpers. Rediscovered

Normally, you’d use partials to manage some common functionality in a single file. For example like this:

Somewhere in your view:

<%= render :partial => 'ads/ad', :locals => {:placement => 'frontpage-banner1'} %>

It’s quite concise, but how about making it even less verbose? Helpers to the rescue:

module AdsHelper
  def ad(placement)
    render :partial => 'ads/ad', :locals => {:placement => placement}
  end
end

And now you can write this in your view:

<%= ad 'frontpage-banner1' %>

Nice! I believe it’s as short as it gets. Sure, if you render this partial only a few times it might not be worth it, but what if you render it 20 or 30 times?

content_tag FTW!

About those one-liners… How about turning this:

<% if logged_in? then %>
<p><%= link_to 'Edit', document_edit_path(@document) %></p>
<% end %>

into this:

<%= content_tag 'p', link_to('Edit', document_edit_path(@document)) if logged_in? %>

I don’t know about you, but to say that I’m impressed would be not enough. Available from Rails 2.0 upwards.

Steve Yegge. Again

Steve Yegge (emphasis added):

So how do you make yourself a superstar? Never stop learning. I’ve heard people say they think this position is a crock, that it’s ludicrous, that you couldn’t possibly spend your whole career learning new things.

But I think differently. I think every program you write should be the hardest you’ve ever written. And that’s what I blog about, mostly. Improving yourself.

It got me thinking today and the more I think about it the more sense it makes. I would go even further with this and say that writing not just hard programs but simply more complicated code is good for you. Not obfuscated nor unreadable but code which is just a bit harder to understand. What I mean is using new constructs, new methodologies, shorter one-liners (but not those super-obfuscated Perl ones), etc.

There are lots of people who will tell you that you should write the simplest code possible (even despite the obvious bloat) because this results in a more maintainable application. This is of course true, but should the maintainability be the ultimate goal? I think that self-improvement should be a higher placed goal. And I think that you self-improve by writing code you need more time to comprehend because the harder code you write now and the more time you spend understanding it in the future the less complicated it becomes. Over time. And that is progress. That is self-improvement. Plus, as a side effect of this, your code is usually more concise.

Now going back to refactoring one of my projects

Mongrel_cluster not starting after hard reboot

Does the following error sound familiar?

** !!! PID file log/mongrel.pid already exists.  Mongrel could be running already.  Check your log/mongrel.log for errors.
** !!! Exiting with error.  You must stop mongrel and clear the .pid before I'll attempt a start.

It usually happens when the server crashes. After that you need to ssh into it, remove the mongrel pid files and start the cluster manually. No more.

I assume you have mongrel_cluster setup properly, ie: project’s config file is in /etc/mongrel_cluster and the mongrel_cluster script has been copied from:
/usr/lib/ruby/gems/1.8/gems/mongrel_cluster-*/resources/
to the /etc/init.d directory. You need to edit the /etc/init.d/mongrel_cluster file:

Change this two bits:

start)
  # Create pid directory
  mkdir -p $PID_DIR
  chown $USER:$USER $PID_DIR

  mongrel_cluster_ctl start -c $CONF_DIR
  RETVAL=$?
;;

and

restart)
  mongrel_cluster_ctl restart -c $CONF_DIR
  RETVAL=$?
;;

to

start)
  # Create pid directory
  mkdir -p $PID_DIR
  chown $USER:$USER $PID_DIR

  mongrel_cluster_ctl start --clean -c $CONF_DIR
  RETVAL=$?
;;

and

restart)
  mongrel_cluster_ctl restart --clean -c $CONF_DIR
  RETVAL=$?
;;

respectively.

Adding the --clean option makes the mongrel_cluster_ctl script first check whether mongrel_rails processes are running and if not, checks for existing pid files and deletes them before proceeding.

You must be using the mongrel_cluster version 1.0.5+ for it to work as advertised (previous versions were buggy). To upgrade do:

gem install mongrel_cluster
gem cleanup mongrel_cluster

Here’s the related mongrel_cluster changeset.

Steve Yegge live

After yesterday’s best read of the month here comes the best show of the day. Which is Steve Yegge, live, talking about branding during 2007 OSCON. Without any slides. 25 minutes.

He also reveals that in his opinion Javascript2 will be the Next Big Language (NBL). I was kind of suspecting this would be it. Coincidently, lately I’ve discovered (what a big word) jQuery. And let me tell you, I’ve never seen any other piece of code, which is so concise and does so many things with so much style. Prototype, dojoToolkit and all other js libraries simply look pale in comparison. I’m hooked on jQuery and use it for every new project, while trying to implement it in my old ones too.

TylkoZyczenia.pl – My third rails app available to the public

TylkoZyczenia.pl – my new Rails website is now live. It’s Polish language only and it will probably stay this way. Basically, it’s a site with collections of wishes for various occasions, like Christmas, New Year, birthdays and so on. At the moment it’s not very different from other, similar websites (and there are lots of them in Poland) apart from the fact that my design, in my humble opinion, is leaner and much more clearer/simple than the others (aka simplicity all the way). I have some ideas to make this site different (read: better) from the others, though. Stay tuned.

It took me about 2 months of intensive, after-hours work. It’s the first version, which is usable to be online (meaning that basic stuff, like registering and adding new wishes work. The TODO list is quite big…). Enjoy!

Tylko życzenia!

Late night capistrano

Excerpt from my current Capistrano cheat sheet:

cap deploy_with_migrations
- will deploy normally and then run 'rake db:migrate' (SCARY!)
- 'cap disable_web' (FIRST!)
- WILL NOT RUN ANY :after_deploy methods (FUCK!)

Now don’t get me wrong, I really love Capistrano (now at 1.4) as it makes my development life a lot easier. It’s just those little bits that bite you in the ass in the most unexpected moment.

Oh, and I’m sure there’s a reasonable explanation for this behaviour.

UPDATE: It has its own ticket now.

Express Kaszubski – my second public Rails app

Express Kaszubski, a local Kaszubian (that’s in Poland) newspaper has just recently decided to stop releasing its printed edition and move entirely to the web. It was my honour to accompany during this move. The online edition took about a month to create. It’s just a basic website at the moment. No comments, no RSS feeds, although the CMS behind the scenes is quite powerful. All in Rails, of course.

Here is the snippet:

Express Kaszubski

And if you haven’t noticed by now, it’s all in Polish.