So whenever Subversion ever tells you “Attempted to lock an already-locked dir”. You say nay, and type “svn cleanup” This command searches you current working copy re-runs any leftover log files and removes any locks in the process.

I personally use Subclipse, the SVN eclipse plugin. To get rid of this error in Subclipse, right-click the offending directory and click Team>cleanup.

Happy coding.

1. Download the latest Binary from here.
2. To keep it clean, let’s unpack the archive and move the folder to /usr/share. Open up a terminal window and type: $ sudo mv ~/Downloads/grails-1.1 /usr/share
3. Change the permissions on these files $cd /usr/share
$sudo chown -R root:wheel grails-1.1/
$sudo chmod 0755 grails-1.1/bin/*

4. Let’s create a symlink to the grails directory $ln -s grails-1.1 grails
5. Finally, let’s add the GRAILS_HOME var to our ~/.profile file and point it to the symlink that we just created. If you’re like me, and don’t find vi particularly easy to use, here’s an easy way to edit your .profile file using TextEdit open ~/.profile

   If for some reason TextEdit is not the default application for this type of file, you can force it to open this file by typing open -a TextEdit ~/.profile
   Here’s an example of what a .profile file might look like when GRAILS_HOME is added: GRAILS_HOME=/usr/share/grails; export GRAILS_HOME
export PATH=/opt/local/bin:/opt/local/sbin:$GRAILS_HOME/bin:$PATH
6. That’s it! Let’s test it out. Type in grails in the Terminal and you should see the following output.
   $grails
Welcome to Grails 1.1 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: /usr/share/grails

No script name specified. Use ‘grails help’ for more info or ‘grails interactive’ to enter interactive mode


To install:

Add the following HTML snippet to the section of your page where you want the timer to be placed

<div id="counter" class="counter">
	<ul class="countdown">
		<li><div class="countdown_num" id="countdown_day"></div><div>Days</div></li>
		<li><div class="countdown_num" id="countdown_hour"></div><div>Hours</div></li>
		<li><div class="countdown_num" id="countdown_min"></div><div>Minutes</div></li>
		<li><div class="countdown_num" id="countdown_sec"></div><div>Seconds</div></li>
	</ul>
</div>
<div id="expired" style="display:none;">
	The deadline has passed.
</div>

Next, add the following CSS to give it some style!

/*COUNTER SPECIFIC STYLES */
.counter{
	width: 610px;
}
.counter ul.countdown{
	list-style-type: none;
	color: white;
	font-weight: bold;
	text-align: center;
}
.counter ul.countdown li{
	float: left;
	background: url(digit.png) no-repeat;
	height:110px;
	width: 105px;
	padding-top: 15px;
}
.counter ul.countdown li div{
	font-size: 15px;
}
.counter ul.countdown li div.countdown_num{
	font-size: 48px;
}
.counter ul.countdown li.no_countdown{
	padding-top:4px;
	background:transparent;
	height:110px;
	width:180px;
}

Finally, here’s the Javascript to make it work. Just add this script to the bottom of your page.

<script type="text/javascript">
         /*
		Countdown Timer
		Based on the "Count down until any date script" - By JavaScript Kit (www.javascriptkit.com)
		Author: (c) 2009 Elbert Bautista
		URL: http://www.egTheBlog.com
		Licence : Open Source MIT Licence
 
	*/
 
	var current="Expired"
	var montharray=new Array("Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec")
 
	function countdown(yr,m,d){
		theyear=yr;themonth=m;theday=d
		var today=new Date()
		var todayy=today.getYear()
		if (todayy < 1000)
		todayy+=1900
		var todaym=today.getMonth()
		var todayd=today.getDate()
		var todayh=today.getHours()
		var todaymin=today.getMinutes()
		var todaysec=today.getSeconds()
		var todaystring=montharray[todaym]+" "+todayd+", "+todayy+" "+todayh+":"+todaymin+":"+todaysec
		futurestring=montharray[m-1]+" "+d+", "+yr
		dd=Date.parse(futurestring)-Date.parse(todaystring)
		dday=Math.floor(dd/(60*60*1000*24)*1)
		dhour=Math.floor((dd%(60*60*1000*24))/(60*60*1000)*1)
		dmin=Math.floor(((dd%(60*60*1000*24))%(60*60*1000))/(60*1000)*1)
		dsec=Math.floor((((dd%(60*60*1000*24))%(60*60*1000))%(60*1000))/1000*1)
		if(dday==0&&dhour==0&&dmin==0&&dsec==1){
			document.getElementById('counter').style.display='none';
			document.getElementById('expired').style.display='block';
			return
		}
		else{
			document.getElementById('countdown_day').innerHTML=dday;
			document.getElementById('countdown_hour').innerHTML=dhour;
			document.getElementById('countdown_min').innerHTML=dmin;
			document.getElementById('countdown_sec').innerHTML=dsec;
			setTimeout("countdown(theyear,themonth,theday)",1000)
		}
	}
 
        // THIS IS JUST TEST DATA FOR THE EXAMPLE, REMOVE
	var deadline=new Date();
	deadline.setDate(deadline.getDate()+5);
	var deadlineYear = deadline.getYear();
	if (deadlineYear < 1000)
	deadlineYear+=1900
        // ---------------------------
 
 
	//MODIFY THIS LINE: enter the count down date using the format year/month/day
        //e.g. countdown(2009, 03, 23);
	countdown(deadlineYear, deadline.getMonth()+1, deadline.getDate());
</script>

That’s it! Check out the final demo here.

There are certainly many ways to do this, but I want to focus on what I’ve found to be a very elegant solution. We’re going to use migrations, so that when you do your initial rake db:migrate, things are setup and ready to go. And if you want to rollback a specific populating of a table, you could do that as well!

The example I’m going to use is a table that needs to hold the 50 US states. Create a migration like the following:

script/generate migration add_states

Now open up the migration file you just created, and make it look something like this (I’m not going to fill in all 50 states for this example):

class AddStates < ActiveRecord::Migration
  def self.up
    %w(AL AK AZ AR CA CO CT DE DC FL).each do |s|
        State.new(:name => s).save
    end
  end
 
  def self.down
    State.destroy_all
  end
end

In the “up” migration you’re iterating through an array of states (which are Strings), and for each one creating a new State object in memory (with whatever attributes you need, in our case just the name), then saving the record to the db with the save method. Easy and elegant.

The beauty is that in the “down” migration, we wipe out everything in the states table, as it should be. Be aware that when you run the down migration, if you have an auto-incrementing primary key id, it does not reset. So if you populated the 50 states, ran the down migration, then ran it again, the id would start counting at 51, not 1.

Let’s go through an example of how to rotate your production.log file. Navigate to /etc/logrotate.d. In there should be one or more config files, which specify what logs to rotate and with what options. My logrotate.d folder already had a few config files in there for apache2, mysql-server, etc. I created a new one and named it ruby.

Open up the newly created file (/etc/logrotate.d/ruby to be clear) and fill it with something like this:

/var/railsapps/myapp/shared/log/production.log {
daily
rotate 12
compress
missingok
copytruncate
}

So the first line points to whichever log file we want to deal with (I just used a sample path, yours is likely to differ). Something interesting you can do is instead of just doing this for production.log, put something like *.log and then logrotate will work its magic on any file in that folder which ends with .log!
Inside the brackets is just a sampling of the options you can put. I won’t go through all of them, just Google “logrotate options” or something like that and you’ll find all of them in no time, with thorough explanations. For the sake of this quick tutorial, I’ll explain a few:

• daily: rotate log files daily (could have also said weekly or monthly)
• rotate 12: keep 12 weeks worth of backlogs
• compress: if you want your log files compressed to save diskspace (uses gzip)

You get the point. I read somewhere that if you are using Mongrel, you need the copytruncate option in order for the log to keep being written to, thus avoiding a restart (not sure of the accuracy of this statement, just a heads up!). To actually USE logrotate, all you have to do is wait for the time period you specified (if daily, wait for the next day) and rotation should happen automatically.

I hope this served as a good intro to rotating your Rails logs, if you have questions please post them!

map.logout '/logout', :controller => 'sessions', :action => 'destroy'

This enables you to say something like this:

redirect_to logout_url

And if you want to pass extra params to that URL? It’s as easy as:

redirect_to logout_url(:some_param => true, :some_other_param => 24)

There was absolutely nothing strange about the table, my controller, or model object. The next day it dawned on me, I thought “I bet one of the column names in my table is a reserved word”. Well, that turned out to be precisely the problem. One of my columns was named type, and that completely threw off ActiveRecord. I also think you cannot name a column open. I’m not sure if there is a complete list of reserved words somewhere, but double-check anytime you name a column something that sounds like it COULD be a reserved word. It could save you hours of mindless troubleshooting!

EDIT:
OK, so here is a list of reserved words that could help: List of Reserved Words in Ruby on Rails

Also, it would be nice to be able to alias columns in your models. In my case, I can’t just change the column name from type to something else, because I’m wrapping an existing table that cannot be altered. If anyone has an elegant solution, feel free to comment!

http://www.smashingmagazine.com/2008/10/12/50-beautiful-movie-posters/

- My personal favorites:

• Alfred Hitchcock’s The Birds
• Pulp Fiction
• THX 1138

Facebook Inspired Auto-Complete Form - One of the best multiple select text forms is on facebook. This post shows you how to do it.

CSS Sprites Using JQuery - A cool post that shows you how to do CSS Sprites using JQuery. Very Useful

JParallax - This is a cool tool from Stephen Band. Think of looking through a camera and having layers of objects at various distances moving around. This library achieves that effect using multiple static images, one for each layer.

Coda Popup Bubble using JQuery - Very cool popup that can be used as a tooltip or on:hover element

Ajax Auto-Suggest - The AutoSuggest class adds a popdown menu of suggested values to a text field. The user can either click directly on a suggestion to enter it into the field, or navigate the list using the up and down arrow keys, selecting a value using the tab key. The values for the suggestion list are to provided as XML (by a PHP script, or similar).

In comes the improved acts_as_taggable_on plugin. In addition to being compatible with Rails 2.1, it has a few more really cool features like having different “categories” or “sets” of tags. I’ll leave you to read all about it here.

But if you’re like me, you already have all sorts of tags and taggings in your existing database, and you REALLY don’t want to wipe all your data and run the acts_as_taggable_on migration from scratch. I found a blog post that got me started on the migration process, but it had a few errors and was incomplete, hence my reason for writing this.

Luckily the database structure between AATOS and AATO is very similar. We’ll get to that in a second. First, you’ll want to install AATO like normal (again, refer to this link).
Note: I was doing this on a Windows machine, and I needed to install git before I could run the script/plugin install git://github.com/mbleigh/acts-as-taggable-on.git. I got it from http://code.google.com/p/msysgit/downloads/list, and at the time of writing the version I installed was Git-1.5.6.1-preview20080701.exe.

Next, you’ll want to generate your migration file, exactly like you did back in the day (which was a Wednesday by the way) when you installed AATOS. So, script/generate acts_as_taggable_on_migration. If you didn’t previously use any tagging plugin, running rake db:migrate now would create two new tables, tags and taggings. But you already have those two tables! So running that migration as is would probably cause all sorts of a mess. What we want to do is edit the migration file to ALTER your existing tables, thus keeping all your precious existing tags around and working.

Note: If you’re committed to doing this upgrade, it is safe to delete your acts_as_taggable_on_steroids folder found in vendor/plugins.

So, we shall change the migration to look like this (read my code comments to understand what’s going on):

class ActsAsTaggableOnMigration < ActiveRecord::Migration
  def self.up
    # this has been modified to upgrade the tables previously created by acts_as_taggable_on_steroids
 
    # get rid of the old table index in the taggings table
    remove_index :taggings, [:taggable_id,:taggable_type]
 
    # these are the three new columns necessary for the new plugin to work
    add_column :taggings, :tagger_id, :integer
    add_column :taggings, :tagger_type, :string
    add_column :taggings, :context, :string
 
    # these are the two new indexes necessary for the new plugin to work
    add_index :taggings, :tag_id
    add_index :taggings, [:taggable_id, :taggable_type, :context]
  end
 
  def self.down
    drop_table :taggings
    drop_table :tags
  end
end

Now, run that migration with rake db:migrate. We still need to make a few changes. Go to your model(s) which actually have tags. Previously you declared something like acts_as_taggable in each of them. You’ll need to change this to specify the tag “category” or “set” like we previously mentioned. So change that acts_as_taggable line to read acts_as_taggable_on :tags. You can put whatever you want in the place of :tags, but I’m just making it generic.

One more step is necessary to get your existing tags working again. In your database, your taggings table now has 3 new columns (all three should be empty). You need to fill in the :context column with the value “tags”, which is what I arbitrarily showed above. If you chose to say acts_as_taggable_on :interests, then the context column needs to be populated with “interests”. That should do it!