RudyGems

Rails 3 doesn't allow "open" as a Named Scope

Mon, 01 Mar 2010 17:21:37 +0000

Rails 3 has involved rewriting pretty much the whole codebase,

Rails 3 gives off the fragrance of a coherent, cohesive framework.

But this one kind of annoys me.

/Users/matthew/.bundle/ruby/1.8/bundler/gems/rails-16a5e918a06649ffac24fd5873b875daf66212ad-master/activerecord/lib/active_record/named_scope.rb:104:in `scope’: Cannot define scope :open because AbcDef.open method already exists. (ArgumentError)

So, in Rails 3, when defining a named scope, we can’t override an existing method.

This all makes sense, we don’t want to inadvertently break anything (although I’d hope your test would catch such a thing)

But unfortunately, every object in Ruby has an “open” method… so “open” suddenly is off the market for named scopes… bummer

I spent most of day trying to sort this out… writing a patch… trying to convince people to apply it… but the rails core guys wouldn’t budge.

So here’s a quick hack I put in an initializer

# config/initializers/allow_open_as_a_named_scope.rb
require 'active_record'
class ActiveRecord::Base
  class << self
    alias :_open :open
    undef_method :open
  end
end

And we’re done…

Kind of annoying though. I use “open” all the time, because it makes sense

I’d prefer it if active record just made a logger.warn, and let me make my own decisions

My Fork of rails, My Example of the bug, My Undef_Method hack

Securing CruiseControl.rb on Nginx

Tue, 09 Feb 2010 10:02:40 +0000

CruiseControl is great

Quick and easy to setup

But takes a few minutes to work out how to secure it.

we start cruise;

cruise@MerlotBuild:~/cruisecontrol.rb$ ./cruise start -d
=> Booting Mongrel
=> Rails 2.3.2 application starting on http://0.0.0.0:3333

Going directly by IP http://94.102.144.37:3333 we get our cruise install.

But that’s not good enough, we need to secure it from the outside world

In Nginx we do this;

server {
  listen 80;
  server_name cruise.matthewrudy.com;
  
  auth_basic "Access";
  auth_basic_user_file /opt/nginx/conf/htpasswd;

  location / {
    proxy_pass http://localhost:3333;
  }
}

And we’re almost done

Except http://94.102.144.37:3333 still works, as mongrel allows requests from any host name

cruise@MerlotBuild:~/cruisecontrol.rb$ ./cruise start -d -b 127.0.0.1
=> Booting Mongrel
=> Rails 2.3.2 application starting on http://127.0.0.1:3333

Does the job… home… secure… safe?

How big is my MySQL database?

Wed, 07 Oct 2009 11:33:00 +0100

mysql> SELECT table_schema,
  sum(data_length) / 1024 / 1024 "data",
  sum(index_length) / 1024 / 1024 "index",
  sum( data_length + index_length ) / 1024 / 1024 "total"
FROM information_schema.TABLES
GROUP BY table_schema \G;

*************************** 1. row ***************************
table_schema: aardvarks_development
        data: 5297.32812500
       index: 4407.93750000
       total: 9705.26562500
*************************** 2. row ***************************
table_schema: aardvarks_test
        data: 0.09375000
       index: 0.25000000
       total: 0.34375000
*************************** 3. row ***************************
table_schema: badgers_development
        data: 13.59375000
       index: 16.60937500
       total: 30.2031250

as you can see, aardvarks_developpment is almost taking up 10gig

if we only care about “test” databases, we can add a condition on “table_schema”

mysql> SELECT table_schema,
  sum(data_length) / 1024 / 1024 "data",
  sum(index_length) / 1024 / 1024 "index",
  sum( data_length + index_length ) / 1024 / 1024 "total"
FROM information_schema.TABLES
WHERE table_schema like "%_test"
GROUP BY table_schema \G;

*************************** 1. row ***************************
table_schema: aardvarks_test
        data: 0.09375000
       index: 0.25000000
       total: 0.3437500

Boom!

(credit to Paul Butcher for the query)

Updating RubyGems on Ubuntu 9.04

Sun, 16 Aug 2009 17:23:50 +0100

I don’t know how many times I’ve had to do this.

But every time I install Ubuntu again, I get this;

matthew@Rudyness:~$ sudo gem update --system
ERROR: While executing gem ... (RuntimeError)
gem update --system is disabled on Debian. RubyGems can be updated using the official Debian repositories by aptitude or apt-get.

The simple fix;

matthew@Rudyness:~$ sudo gem install rubygems-update
Successfully installed rubygems-update-1.3.5
1 gem installed
Installing ri documentation for rubygems-update-1.3.5...
Installing RDoc documentation for rubygems-update-1.3.5...
matthew@Rudyness:~$ sudo /var/lib/gems/1.8/bin/update_rubygems 
Installing RubyGems 1.3.5
RubyGems 1.3.5 installed

RubyGems installed the following executables:
	/usr/bin/gem1.8

matthew@Rudyness:~$ gem --version
1.3.5

From now on you can “sudo gem update —system” as much as you want.

Sweetness.

Installing Ruby 1.9.1 on Ubuntu 9.04

Thu, 23 Apr 2009 00:24:00 +0100

Now, I’m upset that Jaunty Jackalope doesn’t ship with ruby 1.9.1 as default,
and the packaged version is only 1.9.0.

So we’re going to have to build it from source.

And because we’re all progressive people, we’re not even going to worry about suffixing the executables with `1.9` I can’t be bothered to type `gem1.9`

The dependencies are simple;

sudo apt-get install build-essential libssl-dev libreadline5 libreadline5-dev zlib1g zlib1g-dev

Then the usual process…

mkdir ~/src && cd ~/src
wget ftp://ftp.ruby-lang.org/pub/ruby/1.9/ruby-1.9.1-p0.tar.gz
tar -xvf ruby-1.9.1-p0.tar.gz
cd ruby-1.9.1-p0
./configure
make
make test
sudo make install

And to get rails working properly

sudo gem update --system
sudo gem install rails

# and to get sqlite3 working properly
sudo apt-get install sqlite3 libsqlite3-dev
sudo gem install sqlite3-ruby

Done.

I’ll add to this if I notice any problems

Ruby 1.9 becoming the standard?

Fri, 27 Mar 2009 20:11:19 +0000

There’s a lot of talk recently about pushing the Ruby Community onto Ruby 1.9.

Now that’s cool, the more people using 1.9 the quicker the issues will get ironed out

(people need to be spurred into fixing their libraries)

But there is one thing standing in the way of 1.9 being adopted by the whole community, Default Packages

Mac OSX comes with 1.8.6 as standard, Ubuntu 8.10 comes with 1.8.7.

Whitney Houston said “the children are our future”, and that’s exactly who we need to start using 1.9 right from the word go.

With Ubuntu 9.04 (Jaunty Jackalope) and OSX Snow Leopard on their way out soon, surely if they adopted 1.9 as the default, we’d be on the road to success.

However, maybe that’s not going to happen.

A quick look at the packages of Jaunty Jackalope and you’ll see

This package is a dependency package, which depends on Debian’s default Ruby version (currently 1.8.x).

So I guess this thing’s not going to get fixed soon.

Expire eTAGs when you redeploy

Mon, 19 Jan 2009 23:02:00 +0000

Rails 2.2’s eTAG functionality is great.

def show
  @article = Article.find(params[:id])
  if stale_record(@article)
    # do something expensive
  end
end

protected

  def stale_record?(record)
    fresh_when(:etag => [current_user, record], :last_modified => record.updated_at.utc)
    !request.fresh?(response)
  end

“304 NOT MODIFIED” all around!

But this determines freshness based on just the record.
If I deploy a new version of the “show” template eTAG-compliant browsers won’t refresh.

I could build my own way of handling this inside “stale_record?”
But Rails already has a method for dealing with this.

All cache keys are generated through the following code.

if ENV["RAILS_CACHE_ID"] || ENV["RAILS_APP_VERSION"]
  expanded_cache_key << "#{ENV["RAILS_CACHE_ID"] || ENV["RAILS_APP_VERSION"]}/"
end

So what does it mean to be the RAILS_APP_VERSION?
Well, I’m going to mis-use it, and say “it’s the current version of our app”

And Capistrano already gives this to us… it gives us /current/REVISION!!!

Perfect!

A quick “/config/initializers/capified_etags.rb” later

app_version_path = File.join(Rails.root, "REVISION")
if File.exist?(app_version_path)
  ENV["RAILS_APP_VERSION"] = File.open(app_version_path).read.strip
end

Nice.

Let me know if there are any other approaches out there.

setting up a simple git server

Sat, 20 Dec 2008 23:36:00 +0000

On the internet you’ll see people talking about Gitosis, or just giving over all of their git requirements to github.

Github is great, but if you just want to do a small personal project, with an off-site repository, go set up your VPS as your main git server.

Here’s how you do it.

create a “git” user
```
sudo adduser git
```
add your ssh keys to that user
```
ssh-copy-id git@my.com
```
create a “bare” repository on your server
```
mkdir myRepo.git
git --bare init
```

add this as a remote source

git remote add origin git@my.com:myRepo.git
git push origin master

BOOM! that is literally all it takes!

Thanks to CommonThread for his tutorial on doing this.

Rails + Rack Middleware

Wed, 17 Dec 2008 12:09:00 +0000

Rails just released Metal!

Giving us a great framework to build custom Rack processors alongside our application.

Check out this great article over at Soylent Foo.

Recently we had a problem where Microsoft Office was somehow issuing OPTIONS request to our site.

This was blowing up our RESTful controllers that weren’t invited to the OPTIONS party.

We played with Apache rewrites based on REQUEST_METHOD,

but ultimately, we wasted a lot of time fighting against Rails and routing exceptions, blahblahblah.

But now Rails is running off Rack we can deal with it the correct way.

class OptionsCatcher < Rails::Rack::Metal
  def call(env)
    if env["REQUEST_METHOD"] =~ /OPTIONS/i
      [403, {"Content-Type" => "text/html"}, "OPTIONS requests are forbidden"]
    else
      super
    end
  end
end

B00M!

Now this is technically just middleware, and should be declared with a

config.middleware.use OptionsCatcher

and in lib/options_catcher.rb

class OptionsMiddleware
  def initialize(app)
    @app = app
  end
  
  def call(env)
    if env["REQUEST_METHOD"] =~ /OPTIONS/i
      [403, {"Content-Type" => "text/html"}, "OPTIONS requests are forbidden"]
    else
      @app.call(env)
    end
  end
end

but doing it as a Metal makes sense, and is easier than remembering the structure of middleware each time

But there seems to be a problem at the moment with this.

Will try and get a proper Metal working shortly.

has_one_accessor

Sun, 30 Nov 2008 22:51:18 +0000

HasOneAccessor is a plugin for ActiveRecord that solves the problem of having associations that act like a attribute.

Perhaps only a few users have an openid, so it doesn’t make sense to add an :open_id_url column to your :users table.

Instead you create a new model OpenId

class OpenId < ActiveRecord::Base
  belong_to :user
end

class User < ActiveRecord::Base
  has_one :open_id

  def open_id_url
    self.open_id && self.open_id.url
  end

  def open_id_url=(value)
    if value.blank?
      self.open_id && self.open_id = nil
    else
      self.open_id || self.build_open_id
      self.open_id.url = value
    end
  end
end

Now, that’s not too bad. But maybe you didn’t have time to clean it up.

Maybe you deal with it in your controller.

def update
  if params[:open_id_url] && params[:open_id_url].present?
    @user.open_id || @user.build_open_id
    @user.open_id.url = params[:open_id_url]
  end
  ...
end

Now, that’s all fine.

But we all want to make these things easier.

We all want to cast as much code aside.

ConventionOverConfiguration and all that.

Enter has_one_accessor

class OpenId < ActiveRecord::Base
  belong_to :user
end

class User < ActiveRecord::Base
  has_one :open_id
  has_one_accessor :open_id, :url, :allow_blank => false
end

This takes away all the code,

This takes care of building a record if there wasn’t one, of only saving it when you save the User.

It even kills the association if the value is :blank? (if you pass in :allow_blank => false).

B00m, h34dsh0t?

SolrQuery - build your solr queries dynamically in Ruby

Mon, 17 Nov 2008 21:22:00 +0000

I’ve been using ActsAsSolr for about 6 months.

And at work I developed some code to make SOLR queries work a bit like the conditions in ActiveRecord.

Check out my library at Github. http://github.com/matthewrudy/solr_query

SolrQuery.build(:keyword => "Feather duster"
=> "feather duster"

SolrQuery.build(:keyword => "clean",
                :organisation => [organisation1, organisation2])
=> "clean AND organisation:(275 OR 6534)"

Wicked!

Check out the readme for more examples.

UID problems across a shared mount?

Sat, 15 Nov 2008 14:26:00 +0000

We just moved to new Ubuntu servers.

We use file-column (with some modifications) to deal with our file uploads.

deploy@jgp-web01:/var/www/oursite$ ls -l public/uploaded_file/file_name/000/000/051/585/ 
total 4
-rw-r--r-- 1 gerhard www-data 2670 2008-11-15 05:09 MatthewJacobsCV.txt

deploy@jgp-web02:/var/www/oursite$ ls -l public/uploaded_file/file_name/000/000/051/585/ 
total 4
-rw-r--r-- 1 deploy www-data 2670 2008-11-15 05:09 MatthewJacobsCV.txt

If you look carefully, you’ll see one is owned by “deploy” and the other by “gerhard”.

These are mounted by NFS, shared across the two computers.

So these are actually the same file, but with different permissions on each.

A quick use of the “id” command confirmed this;

deploy@jgp-web01:~$ id deploy
uid=1004(deploy) gid=33(www-data) groups=33(www-data),1005(aspire)

deploy@jgp-web02:~$ id deploy
uid=1002(deploy) gid=33(www-data) groups=33(www-data),1003(aspire)

The answer is;

root@jgp-web01:~# usermod -u 10000 deploy

root@jgp-web02:~# usermod -u 10000 deploy

boom!

Now this is resolved, but you’ll have to chown all the existing files, back to `deploy`, else they’ll still be attached to the old uid.

"svn switch —relocate svn://oldserver svn+ssh://newserver"

Wed, 12 Nov 2008 12:21:17 +0000

“svn switch —relocate svn://oldserver svn+ssh://newserver”

- need to move your svn repository?

Welcome home DHH! After a long time, it seems DHH is back,...

Sat, 01 Nov 2008 16:01:00 +0000

Welcome home DHH!

After a long time, it seems DHH is back, actively commiting to rails.

Getting ready for 2.2 to be released, he’s committed 20 times in the past week.

It’s nice to see.

Google App Engine to support Ruby?

Fri, 24 Oct 2008 11:51:00 +0100

A recent post on the Google App Engine blog refers to;

“Support for a new runtime language”

That’s got to be ruby…

Imagine a bespoke Sinatra-style minimal framework, with DataMapper bindings to the Google DataStore.

No doubt it’ll be pretty quick to make it work with Merb as well.

AWESOME.

Why did google never reply to my job application asking to work on it?

(if you haven’t seen the videos from last years Google IO, then they’re well worth watching - here)

"it’s hard enough to push out a great idea, even if you thought of it, and have spent years..."

Sun, 19 Oct 2008 22:06:00 +0100

“

it’s hard enough to push out a great idea,
even if you thought of it,
and have spent years thinking about it.

If a potential investor is going to take the time, money, and bother to steal your idea,
then someone else is going to buy it from you
before they have a chance.

”

- me, talking to Stephen Strudwick about startups, already in Beta, being too scared to pitch to investors!

Rendering layouts that live in /public?

Wed, 15 Oct 2008 21:16:20 +0100

At work we have the following concept.

a “site” has a subset of our content
a “site” has a url - eg. “oursite.com/stickers” or “stickersNOTvicars.com”
a “site” can have its own customised layout, or fall back to the default one

How does this work in code?

site.articles (pretty simple)
a whole load of “route filters” that match the incoming host
the code I’m writing about

So, historically we did

class ApplicationController
  layout :determine_layout
  def determine_layout
    if File.exists?("#{Rails.root}/public/sites/#{@site.id}/application.rhtml")
      "../../public/sites/#{@site.id}/application"
    else
      "site_default"
    end
  end
end

This was a hack, and it breaks with Rails 2.1.1, so after a day or so playing with the internals of ActionView I discovered this;

append_view_path("#{Rails.root}/public/sites")

And it works!

We just need to set;

"#{@site.id}/application"

as our layout, and we’re away.

Site-specific layouts that live in /public!

"I didn’t get drunk enough to try the Goggles. Next time!"

Wed, 15 Oct 2008 00:13:48 +0100

“I didn’t get drunk enough to try the Goggles. Next time!”

Google Goggles are good enough for me? On Monday its the LRUG...

Sun, 12 Oct 2008 15:17:00 +0100

Google Goggles are good enough for me?

On Monday its the LRUG quiz.

Can Google’s entry into drunken embarassment prevention really hold out against my mathematical skills?

Am I just too elite?

At level 5 (the hardest) we still get sums like “6x9”!

Does my mathematical ability really drop that much?

We’ll see tomorrow!

What would happen if you ripped out your Db server?

Sat, 11 Oct 2008 16:42:14 +0100

Does your application and architecture really have failover?

If I broke into your datacentre, ripped out, and hid one of your servers, what would happen?

Is your architecture the biggest hurdle to scaling your web app?

Blain Cook and Joe Stump not talking about Twitter’s scaling issues.