Red Squirrel Stumblog

A quick way to find slow Rails actions

Wed, 23 Jul 2008 12:13:00 -0500

tail -10000 log/production.log | egrep "Completed in [0-9]{2,}"

via RailsMachine support

Grouping by Object#hash

Tue, 22 Jul 2008 01:20:28 -0500

I liked this little idiom from Tobias.

servers = [ 'memcache1', 'memcache2', 'memcache3' ]
servers[ 'product-1' % servers.size ]

"Net::SMTPFatalError" with "553 5.0.0" and "User address required"

Tue, 17 Jun 2008 08:37:00 -0500

If you ever get this combination of errors while sending email, you should check the raw data for your “To:” field. I stupidly checked only the email address, rather than the raw data, which included the name, which, for some odd reason had backslashes for the last name. In other words, SMTP doesn’t like to send email to “John \\” , in fact it hates sending email to these sorts of people and will do its best to ruin your afternoon if you attempt it.

Rails 2.1 breaks attachment_fu

Tue, 03 Jun 2008 15:17:07 -0500

Here’s a patch
http://pastie.textmate.org/145188

History Blog Meme

Sat, 19 Apr 2008 12:42:00 -0500

history 1000 | awk ‘{a[$2]++}END{for(i in a){print a[i] ” ” i}}’ | sort -rn | head

95 cd
72 ls
52 svn
49 rake
27 exit
24 p
22 sudo
20 mimi
16 cap
15 git

via objo

One man's fight to disable Ferret during tests/specs

Wed, 19 Mar 2008 10:50:00 -0500

module ActsAsFerret
  module InstanceMethods
    # Overriding these so we don't hit DRb
    def ferret_create; true; end
    def ferret_update; true; end
    def ferret_destroy; true; end
  end
end

Reverting in git

Thu, 06 Mar 2008 16:07:57 -0600

git reset —hard

TextMate regex for removing newlines in CSV

Fri, 22 Feb 2008 07:44:59 -0600

Find: (,"[^"]+)\n([^"]+")
Replace: $1 $2

This will need to be run repeatedly until it doesn’t match anymore because it only removes one newline from a field at a time and some fields may have multiple newlines.

Combined logging for Sinatra and ActiveRecord

Thu, 21 Feb 2008 16:48:16 -0600

ActiveRecord::Base.logger = Logger.new(SOME_LOG_NAME)
Sinatra::Environment.prepare_loggers(ActiveRecord::Base.logger)

Close all tabs in TextMate

Fri, 01 Feb 2008 10:11:02 -0600

Command - Control - W

dup vs. clone

Mon, 31 Dec 2007 12:32:00 -0600

You might think that ActiveRecord::Base#dup is what you want, but you really want clone.

ActiveRecord's QueryCache#uncache

Sun, 09 Dec 2007 06:20:00 -0600

Sometimes you need to compare an attribute of an in-memory ActiveRecord instance against its attribute in the database. The way I usually do that is to grab a fresh instance from the database like this:

class Something < ActiveRecord::Base
  def previous(attribute)
    self.class.find(id)[attribute]
  end
end

That worked just fine in Rails 1.2. But Rails 2.0 has request-scoped query caching enabled by default, meaning that if you have already executed the same SQL that is generated by find(id), you’re going to get the exact same instance back from that call to find. This makes it impossible to compare in-memory attributes against attributes stored in the database.

The solution is to use ActiveRecord’s uncache method. This is a class method, so you’ll need to grab your class to call it like this:

class Something < ActiveRecord::Base
  def previous(attribute)
    self.class.uncached { self.class.find(id)[attribute] }
  end
end

finder_sql String gets eval'd later

Mon, 03 Dec 2007 11:10:00 -0600

If you ever need to use ActiveRecord’s has_many with finder_sql, remember that the key to finder_sql is that the String get eval’d in the context of the ActiveRecord instance rather than the ActiveRecord class. So make sure you use single quotes! This prevents the String from being interpolated too soon.

Do this:

has_many :foos,
  :finder_sql => 'select ... where some_id=#{id}'

Not this:

has_many :foos,
  :finder_sql => "select ... where some_id=#{id}"

In the former case, the #{id} will be the id of the ActiveRecord instance. In the latter case, the #{id} will be the id of the ActiveRecord class.

Watch out for ISO-8859-1 on Rails

Fri, 16 Nov 2007 16:21:00 -0600

Rails uses a UTF-8 charset by default. If you have latin1 on the backend, you’ll end up with a questions mark (yes, a “?”) instead of a ® on the front end. Here’s one way to fix it, but be sure to heed Brian’s comment.

Do NOT require Rails models in Rails unit tests

Wed, 14 Nov 2007 21:18:15 -0600

When the test runs, it will load the class twice. Loading the class twice means that all of the model’s lifecyle hooks will get called twice.

InPlaceEditor loadTextURL changed to GET

Wed, 24 Oct 2007 12:37:58 -0500

In the latest Scriptaculous InPlaceEditor, the loadTextURL will use a GET request. If you’re on Rails and using RESTful Resources for that action, make sure to update your routes.rb from :post to :get.

MySQL gem: NSLinkModule() error

Wed, 10 Oct 2007 11:12:40 -0500

If you’re getting this error when you try to connect to MySQL through Ruby, follow these instructions.

ActiveRecord predicate method

Tue, 02 Oct 2007 06:18:24 -0500

Keep in mind that you can use a predicate method to access your boolean attributes in the Ruby way.

  placement = ImagePlacement.create!(:ignored => true)
  placement.ignored?  # true

update_attribute vs. update_attributes

Thu, 27 Sep 2007 16:29:39 -0500

When do you use one or the other? (Hint: the answer does not depend on whether you want to update one or many attributes.) The most important difference between these methods is that update_attribute bypasses validations.

Unsettable ActiveRecord::Base attribute

Thu, 27 Sep 2007 07:15:23 -0500

If your ActiveRecord is ignoring your attribute, make sure to check that your model class isn’t restricting which attributes are accessible. Like, say, if you’re using the restful_authentication plugin…

  attr_accessible :login, :email, :password, :pass...

This method is a nice way to lock down which attributes can be changed in an ActiveRecord, but it can be maddening when you’re trying to add a new attribute and you didn’t notice the attr_accessible declaration.