RudyGems

cd -Tmp-

Tue, 28 Jun 2011 07:16:16 +0100

How do I cd to a directory starting with a hypen (-)?

# /var/folders/*whatever*/ has a folder named '-Tmp-'
$ ls
-Caches-/ -Tmp-/ 

# lets try and CD there
$ cd -Tmp-
-bash: cd: -T: invalid option
cd: usage: cd [-L|-P] [dir]

# or maybe make sure its a directory
$ cd -Tmp-/
-bash: cd: -T: invalid option
cd: usage: cd [-L|-P] [dir]

# try and escape the first -
$ cd \-Tmp-
-bash: cd: -T: invalid option
cd: usage: cd [-L|-P] [dir]

# quote it
$ cd '-Tmp-'
-bash: cd: -T: invalid option
cd: usage: cd [-L|-P] [dir]

# double quote it
$ cd "-Tmp-"
-bash: cd: -T: invalid option
cd: usage: cd [-L|-P] [dir]

# escape it in the quotes
$ cd '\-Tmp-'
-bash: cd: \-Tmp-: No such file or directory

# escape it in the double quotes
$ cd "\-Tmp-"
-bash: cd: \-Tmp-: No such file or directory

# try a "./" hack
$ cd ./-Tmp-/

$ echo "WHOOP"
WHOOP

Fed up of `bundle exec rake`? Control your `rage`!

Thu, 02 Jun 2011 05:29:00 +0100

For the past year we’ve all been happy.

rake was stable at 0.8.7

You could run

rake

In any project and it’d just work.

But now, with the release of rake 0.9.0, sometimes we get this

RudiMac:3rdhome matthew$ rake
rake aborted!
You have already activated rake 0.9.0,
but your Gemfile requires rake 0.8.7.
Consider using bundle exec.

(See full trace by running task with --trace)

And there’s a simple solution.

RAGE!

#!/usr/bin/env bash
if [ -f Gemfile ]; then
  bundle exec rake $@
else
  rake $@
fi

Either copy and paste the gist into an executable (~/bin/rage maybe)

Or follow these instructions;

git clone git://gist.github.com/1003927.git ~/rage-gist
mkdir ~/bin
cp ~/rage-gist/rage ~/bin/
chmod a+x ~/bin/rage

As long as ~/bin is in your path you should be set.

rage db:migrate test --trace

BOOM!

I forgot to commit to a feature branch!

Wed, 18 May 2011 11:45:00 +0100

So I just committed to master

commit b17a1fbe8f5d59c24a1f2bb50c9905f8345263f5a
Author: Jeffrey Giraffe <Jeffrey.T.Giraffe@gmail.com>
Date:   Wed May 18 18:22:22 2011 +0800
  Started work on an exciting new feature.

But I shouldn’t have.

All features should be in a “feature branch”

How do I move my commit onto a different branch?

Luckily I haven’t pushed yet.

So just start my “feature branch” right now.

git checkout -b exciting-new-feature
git push origin exciting-new-feature

Then go back to master, and undo the commit

git checkout master
git reset --hard HEAD~1

Or if there are 3 commits

git reset --hard HEAD~3

Of course, if I’ve already pushed this would be a little more tricky.

I suggest (for verbosity) you shouldn’t try to do anything fancy.

Just revert it

git revert HEAD

and humbly explain why

Revert "Started work on an exciting new feature."

This commit is not ready to be on master yet,
and has been moved onto the branch "exciting-new-feature"

This reverts commit b17a1fbe8f5d59c24a1f2bb50c9905f8345263f5a.

Boom!

Running a Test Case only when we have internet

Tue, 17 May 2011 12:08:00 +0100

So I have some tests for geocoding, that I want to be run live.

test "geocoding" do
  record = Address.create!(:address => "Pretty Cottage, Winding Road, Beautiful Country")
  assert_equal 51.59011, record.latitude
  assert_equal -2.995398, record.longitude
end

Of course, these will fail when there’s no internet.

My choices;

mock the geocoding API
let them fail
only run this test when there’s internet

I chose the latter.

How do I know I have internet connection?

Can I ping google?

system "ping -q -c 1 -t 1 google.com 1> /dev/null" #=> true / false

Complication!

the above works on OSX (where -t1 sets a timeout of 1 second)

but on Linux -t has a different meaning, and -w1 sets the timeout

Compromise: ignore timeouts for the moment

system "ping -q -c 1 google.com 1> /dev/null" #=> true / false

Stick this in a method

def requires_internet!
  if can_ping_google?
    yield
  else
    flunk "this test needs to be run when there is internet"
  end
end

Now incorporate this into our test.

test "geocoding" do
  requires_internet! do
    record = Address.create!(:address => "Pretty Cottage, Winding Road, Beautiful Country")
    assert_equal 50.0, record.latitude
    assert_equal -0.3, record.longitude
  end
end

Done.

Here’s the gist. Fork it and make it better!

I broke RubyGems.org

Fri, 01 Apr 2011 04:52:00 +0100

Yes that’s right.

I broke RubyGems.org.

No April Fools Joke! (although this did happen after midnight HKT)

… I’ve hidden the cause so they have a chance to fix it…

… but its a unicode thing …

I packaged it with gem-this, and did a `gem push` it turned out http://rubygems.org was down!

I went to bed hoping it would go away, and woke up on April 1st morning to find an email;

Hi Matthew! Looks like you just found a bug that made our homepage unhappy.

=> #<Rubygem id: 39928, name: …,

I straight up deleted that gem. Can you send or paste the gem/gemspec
with that so we can make sure this doesn’t happen again?

-Nick

So, there you go!

Rubygems.org currently can’t support unicode gem names!

Upgrading Postgres 8.4 to 9.0 with Homebrew

Wed, 23 Feb 2011 07:35:00 +0000

I hoped it’d be as simple as a `brew install postgresql`

And it almost was.

But…

RudiMac:merlot matthew$ tail -f /usr/local/var/postgres/server.log
FATAL:  database files are incompatible with server
DETAIL:  The data directory was initialized by PostgreSQL version 8.4, which is not compatible with this version 9.0.3.

How do I fix the data files?

Turns out there is a `pg_update` method to do this for you.

But it requires a bit of manual work.

# First of all stop the server
launchctl unload -w ~/Library/LaunchAgents/org.postgresql.postgres.plist

# backup the old data directory
mv /usr/local/var/postgres /usr/local/var/postgres.old

# now create a fresh postgres 9 data directory
initdb /usr/local/var/postgres

Now we’re ready to do the upgrade.

pg_upgrade -d /usr/local/var/postgres.844/ -D /usr/local/var/postgres -b /usr/local/Cellar/postgresql/8.4.4/bin -B /usr/local/Cellar/postgresql/9.0.3/bin
...
Upgrade complete
----------------

Boom Ting

Now just add the launch control back in and we’re off.

cp /usr/local/Cellar/postgresql/9.0.3/org.postgresql.postgres.plist ~/Library/LaunchAgents
launchctl load -w ~/Library/LaunchAgents/org.postgresql.postgres.plist

Hong Kong Ruby Group Christmas Photo

Fri, 17 Dec 2010 01:04:18 +0000

Hong Kong Ruby Group Christmas Photo

Javascript parseInt() may not do what you expect!

Fri, 03 Dec 2010 07:59:19 +0000

I was shocked today to find I’d introduced a bug.

It manifested itself like this;

This might seem ok.

Except the “Number of repayments” is set by javascript as;

the number of days interest

less the number of days before repayment begins

Looking at the dates, the “number of days before repayment begins” should be 2.

But the difference is -6.

Something is wrong.

And the answer is here;

var date_from_field = function(field_id) {
var field = $(“#”+field_id);
var year, month, day;

var date_bits = field.val().split(“-“);
var year = parseInt(date_bits[0]);
var month = parseInt(date_bits[1]);
var day = parseInt(date_bits[2]);

return new Date(year,month-1,day);
};

I take a date field

<input type=”date” value=”2010-12-08” />

I grab the value

“2010-12-08”

I split it into year, month, and day

[“2010”, “12”, “08”]

I turn them into integers

[2010, 12, 0]

Then I make them into a date

new Date(2010,11,0); // Tue Nov 30 2010

No problem!

Except…

“2010-12-08” != Tue Nov 30 2010

The problem is

parseInt(“08”) == 0

parseInt(“08”, 10) == 8

“08” is 0 in octal

Always use parseInt(something, 10)

Bundler as a Gemfile dependency

Wed, 24 Nov 2010 09:39:00 +0000

Bundler is still a work in progress, so you can expect things to change.

One of these things that has changed between Bundler 1.0.6 and Bundler 1.0.7 is that the “METADATA” field has been removed.

So I’m running Bundler 1.0.7 (with no METADATA) and my colleagues are running 1.0.6 (with METADATA)

I keep getting this diff.

$ git diff Gemfile.lock
diff —git a/Gemfile.lock b/Gemfile.lock
index ec585b3..ee6ba65 100644
—- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -221,3 +221,7 @@ DEPENDENCIES
   whitelist_mail_proxy
   will_paginate!
   zipruby
-
-
-METADATA
- version: 1.0.6

I want bundler to manage itself

# self-referential
gem “bundler”, “>=1.0.7”

And it works

but the message is a bit unpretty

RudiMac:merlot matthew$ bundle install

Fetching source index for http://rubygems.org/
Bundler could not find compatible versions for gem “bundler”:
In Gemfile:
bundler (>= 1.0.7)

Current Bundler version:
bundler (1.0.6)

Your version of Bundler is older than the one requested by the Gemfile.
Perhaps you need to update Bundler by running `gem install bundler`.

I need to use “gem install”?

I wonder if we can patch bundler to install itself.

I recommend you always have a “>= x.x.x”… just for jokes try setting

gem “bundler”, “1.0.6”

Even more Ruby in Chinese

Tue, 23 Nov 2010 10:26:00 +0000

I realised I can write even more Ruby in Chinese.

The only gotchas are;

don’t attempt to use Chinese punctuation （”‘＝＋－，。）
it doesn’t recognise Chinese as uppercase, so you can’t start a class or Constant name with a chinese character

So here is my code.

# encoding: utf-8

class C动物

  def initialize(名字)
    @名字 = 名字
  end
  attr_reader :名字

  def 朋友?(别的)
    true
  end

  def 吃了?
    false
  end

end

class C狗 < C动物
  
  def 朋友?(别的)
    !别的.is_a?(C马泰)
  end

end

class C人 < C动物
end

class C马泰 < C人
  
  def 吃了?(别的)
    别的.is_a?(C狗)
  end

end

我=C马泰.new("马泰")
puts "我的名字是#{我.名字}"
她=C人.new("张学敏")
puts "她的名字是#{她.名字}"

狗=C狗.new("阿财")
puts "狗的名字是#{狗.名字}"

puts "狗是我的朋友吗？#{我.朋友?(狗)}"
puts "我是狗的朋友吗？#{狗.朋友?(我)}"

puts "狗吃了我吗？#{狗.吃了?(我)}"
puts "我吃了狗吗？#{我.吃了?(狗)}"

See the full gist at https://gist.github.com/711563

Maybe I should write a plugin for rails.

Ruby in Chinese

Mon, 11 Oct 2010 13:16:28 +0100

in Ruby 1.8, if you try and assign a variable

你=”ni3”

you’ll get an error

Invalid char `\344’ in expression
Invalid char `\275’ in expression
Invalid char `\240’ in expression
syntax error, unexpected ‘=’
你= “ni3”

But in Ruby 1.9 it actually works.

You just need to add a magic “coding: uft-8” header to your ruby file.

# coding: utf-8
你= “ni3”
好= “hao3”
puts(你+好)

Wham!

matthew@RuPro:~$ ruby chinese.rb
ni3hao3

(if you can’t write chinese, steal my gist http://gist.github.com/613670)

How to delete a file from Git History

Wed, 15 Sep 2010 11:40:00 +0100

I always think about this problem;

What happens if I accidentally commit my password into a git repository?

Surely it’ll be there forever?

Oh man… I just committed a 700mb video file into the repository

It’s going to take forever to deploy…

I’ve always known “get rebase” will probably be the answer

Luckily ProGit knows exactly what to do.

git filter-branch —tree-filter ‘some-bash-command’ HEAD

So here’s my example of how to use it.

I’ve accidentally added a picture of my bum to this rep.

$ git show 84c344
commit 84c344c1874736a6d063ed45abe21e20815525b9
Author: Matthew Rudy Jacobs <MatthewRudyJacobs@gmail.com>
Date: Wed Sep 15 18:25:35 2010 +0800

add my bum

diff —git a/mybum.jpg b/mybum.jpg
new file mode 100644
index 0000000..018be38
—- /dev/null
+++ b/mybum.jpg
@@ -0,0 +1 @@
+a picture of my bum

so let’s try and wipe it from history.

$ git filter-branch —tree-filter ‘rm -f mybum.jpg’ HEAD
Rewrite 76a50a3b1b3263d84517c8e6241ec0bf2bf36fdc (4/4)
Ref ‘refs/heads/master’ was rewritten

now commit 84c344 is still there, but it is not in our branch.
Looking at git log, I can see it’s been rewritten to f59366

$ git show f59366
commit f59366420a8b753de5a0d2812e0abbfb95fccfdf
Author: Matthew Rudy Jacobs <MatthewRudyJacobs@gmail.com>
Date: Wed Sep 15 18:25:35 2010 +0800

add my bum

so my bum is no longer there. In the working tree, or in history.

Right now DON’T git pull it will merge your commits with the original commits.

You’ll have achieved nothing (except doubling the number of commits)

I don’t have an elegant solution… but this seems the only way.

delete all remote repositories

and push to them again

I’m sure there’s a better way… but I haven’t found it.

Here’s my example repo http://github.com/matthewrudy/git-rebase-test

go play!

git pp (git push && git pull)

Wed, 08 Sep 2010 08:09:09 +0100

I am addicted to committing (not commitment).

I make small, distinct commits all the time.

But the consequence of this is

$ git push origin master

To git@myServer:myRepo.git
! [rejected] master -> master (non-fast-forward)
error: failed to push some refs to ‘git@myServer:myRepo.git’

To prevent you from losing history, non-fast-forward updates were rejected

Merge the remote changes (e.g. ‘git pull’) before pushing again. See the
‘Note about fast-forwards’ section of ‘git push —help’ for details.

I hate getting push failures.

But I don’t trust myself to do a pull beforehand.

Enter a git alias!

$ cat ~/.gitconfig
[alias]
pp = !sh -c ‘git pull $0 $1 && git push $0 $1’

Now I am free to “git pp origin master” as much as I want.

$ git pp origin master
From myServer:myRepo
* branch master -> FETCH_HEAD
Already up-to-date.
Everything up-to-date

SAFE!

OR logic in gmail filters

Fri, 27 Aug 2010 18:57:56 +0100

I don’t want to have to read all the emails from my old job,

but I do want to read some of them.

So the obvious answer is using gmail filters, to tag, and archive the ones I don’t want.

It turns out the emails I don’t care about are sent to

notifications@somedomain.com and something-notify@otherdomain.com

I guess it makes sense, but in the filter box we can use the “OR” keyword

notifications@somedomain.com OR notify@otherdomain.com

Boom ting!

Stop adding methods to Symbol just to make your DSL look pretty!

Fri, 18 Jun 2010 04:16:00 +0100

I remember the first time I saw Datamapper.

I liked saying “:something.gt something_else”.

It was pretty.

But after a while I realised it wasn’t necessary.

So why are we still building APIs that involve extending Symbol?

I saw this on an extension called Plucky for MongoMapper

Ruby Enterprise Edition still faster than Ruby 1.9.2?

Wed, 02 Jun 2010 05:40:00 +0100

With Ruby 1.9.2 due to ship on July 31st, I thought I’d take Ruby 1.9.2 preview 3 for a spin.

A quick…

rvm install ruby-1.9.2-preview3

gem install rails prawn erubis

… and we’re done.

But is it any faster than REE?

What does it mean to be faster?

Perhaps all I care about is how fast my tests run

rvm use ruby-1.9.2-preview3

time rake

rvm use ree

time rake

# repeat..

My app:

Rails 2.3.6
rails_xss
postgres
~25 models
~25 controllers

My test suite:

~1700 assertions
~95% code coverage

Results;

So REE is consistently 10% faster at running my test suite than Ruby 1.9.2-preview3

Does this matter?

Probably not… but maybe I can use those extra 5 seconds.

(can’t wait to see if the Phusion.nl guys can make Ruby 1.9.2 faster… )

ssh -D is your friend!

Tue, 04 May 2010 03:53:29 +0100

Are you stuck behind a firewall?

Does your work block access to facebook?

Do you want to watch English Telly from abroad?

SSH -D is your friend.

All you need to bypass the firewall;

ssh access to a VPS
ssh -D8080 me@myserver.com // keep this open
go to your browser
set “connect via SOCKS proxy” on port 8080
keep the ssh connection open
voila!

Your internet access is now piped via your VPS.

This means;

if it is in the UK you can access iPlayer
if it is in the US you can access Hulu
if you were in China you can access… everything

Boom ting!

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)