Andi Schacke's Developer Blog

simple-navigation Version 3

2011-02-28T09:54:00.004+01:00

This post is long overdue. The new version of simple-navigation is a complete rewrite and can now be easily extended to support any ruby based webframework.

The key features of the new version 3 are:

supports Ruby 1.9.2
supports Rails 3
supports Sinatra
supports Padrino
much cleaner code due to decoupling of rails
added more renderers (breadcrumbs, text only, links only in addition to the default html list renderer)

More information can be found on the github page and the wiki. Please report any issues or just post to the mailing list.

There is also a new public project with a sample application running with Rails2, Rails3, Sinatra and Padrino.

Installing ruby with rvm using local readline and iconv

2010-10-26T13:17:00.002+02:00

To install ruby with rvm using your local readline and iconv libraries on SnowLeopard, execute

rvm install 1.8.7 -C --with-readline-dir=/usr/local,--with-iconv-dir=/usr/local,--build=x86_64-apple-darwin10

Simple Navigation Plugin Version 2

2009-10-10T13:23:00.010+02:00

About six months ago I wrote about the first release of the simple navigation plugin. It's a GemPlugin to generate the navigation for your ruby on rails applications.

As far I can judge from the feedback I got from the community it seems like a lot of people are using the plugin. So I'm really happy to announce version 2 of the simple navigation plugin.

The main new features are

create as many navigation levels you like (so far it was limited to primary and sub navigation
the active navigation item gets highlighted automatically (no more explicit configuration of the active item in the controllers needed)

Please check out the

wiki on github
source code on github
the rdoc documentation

and see some live examples on the demo page.

For providing feedback or get help visit the discussion group or drop me a line on github.

Making ActionMailer testable

2009-10-06T11:59:00.002+02:00

If you ever create a custom subclass of ActionMailer you'll be having a hard time to test it. That's because - by default - you cannot access the ActionMailer instance after creating a mail. To make ActionMailer testable you have to make its new-method public:

    1 class ActionMailer::Localized < ActionMailer::Base
    2   
    3   #to make ActionMailer testable
    4   public_class_method :new
    5   
    6   private
    7 
    8   #we would like to test that the correct template is set
    9   def initialize_defaults(method_name)
   10     super
   11     @template = "#{I18n.locale}_#{method_name}"
   12   end
   13   
   14 end

With that change it's easy to test the initialize_defaults-method (as shown here using rspec):

    1 describe ActionMailer::Localized do
    2   
    3   before(:each) do
    4     @localized_mailer = Class.new(ActionMailer::Localized) do
    5       def mailer_method(mail_object); end
    6     end.new
    7     @localized_mailer.stub!(:render)
    8     I18n.locale = 'de'
    9   end
   10 
   11   describe 'after being initialized' do
   12     before(:each) do
   13       @localized_mailer.create!('mailer_method', Object.new)
   14     end
   15     it "should have the localized template name set" do
   16       @localized_mailer.template.should == 'de_mailer_method'
   17     end
   18   end
   19   
   20 end

Localized ActionMailer Templates for Rails

2009-10-06T11:38:00.005+02:00

Rails actually does support localized templates, however, this does not apply for localized ActionMailer templates (yet?). Even if you add the correct locale to your mailer template names, ActionMailer does not choose the one based on the current locale.

It's really easy to fix this:

Just create a subclass of ActionMailer::Base and override the initialize_defaults method as shown below. Then let your mailers inherit from your new subclass.

    1 class ActionMailer::Localized < ActionMailer::Base
    2   
    3   private
    4 
    5   # we override the template_path to render localized templates (since rails does not support that :-( )
    6   # This thing is not testable since you cannot access the instance of a mailer...
    7   def initialize_defaults(method_name)
    8     super
    9     @template = "#{I18n.locale}_#{method_name}"
   10   end
   11   
   12 end

Define your desired template name as shown on line 9, just do not add your locale as dot-notation at the end of the file. E.g. method_name.de.text.plain.erb will not work.

Slow ruby 1.8 performance on MacBook Pro with Leopard

2009-05-14T20:16:00.004+02:00

Recently I started to get really really bored about how sluggish my rspec-tests were running. The weird thing was: the specs run about 5 times faster on my iMac than on the MacBook. Same situation for loading the rails-environment (which is part of running the specs...).

After googling some time I found this blog entry by Barry Hess.

Conclusion: I followed the Hivelogic tutorial to install ruby. They recommend to compile ruby with certain options (e.g. --enable-pthread). This leeds to bad ruby performance on MacBooks (at least the model I have). If you compile ruby without any options, it runs much (and I mean much) faster. Loading the rails enviroment dropped from 5.5s to 1.5s. Specs also run about 5 times faster! If you're a test driven developer, you know what that means in terms of productivity.

I'm quite sure that a lot of rubyists have that problem, but are not aware of it.

Update: this article also applies for Snow Leopard.

Installing the mysql gem for ruby 1.9.1

2009-04-01T13:21:00.005+02:00

I recently tried to install the mysql gem for ruby 1.9.1 on my macbook (OSX 10.5.6). I started with the 'usual' command to install the (modified) mysql gem:

$ sudo gem19 install kwatch-mysql-ruby --source=http://gems.github.com/ -- --with-mysql-config=mysql_config

The gem was compiled and installed correctly, but I got the following error when requiring 'mysql':

LoadError: dlopen(/usr/local/lib/ruby19/gems/1.9.1/gems/kwatch-mysql-ruby-2.8.1/lib/mysql.bundle, 9): Library not loaded: /usr/local/mysql/lib/mysql/libmysqlclient.15.dylib
Referenced from: /usr/local/lib/ruby19/gems/1.9.1/gems/kwatch-mysql-ruby-2.8.1/lib/mysql.bundle
Reason: image not found - /usr/local/lib/ruby19/gems/1.9.1/gems/kwatch-mysql-ruby-2.8.1/lib/mysql.bundle

The problem is that the mysql gem tries to load libmysqlclient.dylib from the wrong directory. The following command resolved the problem:

$ sudo install_name_tool -change /usr/local/mysql/lib/mysql/libmysqlclient.15.dylib /usr/local/mysql/lib/libmysqlclient.15.dylib /usr/local/lib/ruby19/gems/1.9.1/gems/kwatch-mysql-ruby-2.8.1/lib/mysql.bundle

the first param ist the incorrect path which is used by the mysql.bundle, the second param is the correct path to be used instead and the third param is the path to the mysql.bundle. Adapt the params to your needs.

Simple Navigation Plugin for Rails

2009-03-31T20:09:00.010+02:00

Over the last two weeks, I've been working on the simple-navigation plugin which you can use to create the main navigation for your rails app.

In the last year, I built several apps and had to repeatedly implement similar code for creating a navigation. Thus, I thought it would be helpful to have a plugin which generates the code for the navigation and can easily be configured.

Please check out the online demo on simple-navigation-demo.andischacke.com or checkout the wiki on github.

I'd appreciate your feedback on any missing features or bugs, just go to the simple navigation discussion group or leave a comment here.

Update: This post is about an old version of the simple navigation plugin. Please see this post for the new version.

Update: The gem is now ruby 1.9.1 compliant (as of version 1.3.1)

Select the first n lines of a file

2009-03-26T16:24:00.002+01:00

On linux, to select the first 1000 lines of a file and write it to another file use

head -n1000 file_name > new_file_name

Remove the first line of a file with sed

2009-03-26T11:07:00.002+01:00

If you need to remove the first line of a file use (on linux)

sed 1d file_name > new_file_name

Convert a file to UTF8

2009-03-26T10:55:00.004+01:00

On linux, if you want to change the encoding of a file from ISO-8559-1 to UTF8 use

iconv -f ISO-8859-1 -t UTF8 file_name > new_file_name

To get a list of supported encodings use

iconv -l

Problem with rcov and ruby 1.8.7

2009-03-24T15:04:00.006+01:00

I'm running ruby 1.8.7 and got the following error when running rcov (0.8.1.2.0):

usr/local/lib/ruby/1.8/rexml/formatters/pretty.rb:131:in `[]': no implicit conversion from nil to integer (TypeError)

To fix it change the following line in lib/rcov/report.rb of your rcov gem

if RUBY_VERSION == "1.8.6" && defined? REXML::Formatters::Transitive

into

if ["1.8.7", "1.8.6"].include?(RUBY_VERSION) && defined? REXML::Formatters::Transitive

With that modification rcov runs without problems again.

Don't stop at Rails, check out Seaside!

2008-11-16T15:42:00.005+01:00

In order to develop web apps, I have struggled with Java/Tomcat/Struts for several years. Then there was Ruby on Rails and I thought: wow, what a framework, it can't get any easier... I was wrong. There's Seaside. Seaside is a Smalltalk based web application framework. Take Rails, remove routing and request/response handling, start thinking in object oriented components and let's change the way we think of developing web apps. Welcome to the seaside. And the best thing is: if you have mastered Ruby on Rails, it's quite easy to get into Seaside.

Here are some resources to start with:

Squeak by example (a free book introducing Smalltalk/Squeak)
The Seaside homepage
Seaside Tutorial (by the Hasso Plattner Institute)
Lukas Renggli's Website (one of the core developers of seaside)

Once you have got rid of your resistance against the Smalltalk syntax and the somewhat weird looking windows of Squeak you will be amazed how easy it is to develop web apps with Seaside. I will still be working with Ruby on Rails most of my time but Seaside definitely got my attention.

Code Syntax Highlighting on Web Pages with TextMate

2008-10-08T18:31:00.006+02:00

Somehow I felt that there must be an easier way to achieve syntax highlighting on web pages than I described in this previous post. So after thinking and googling for some more time I came accross this cool function in TextMate:

Bundles -> TextMate -> Create HTML from Document

This creates an HTML-page of your current document. Voilà. And it even includes the CSS needed to make the page look like your current TextMate theme.

Update: It also works for displaying CSS, HTML and Javascript! (and probably for every other language which can be displayed by TextMate)

Add a character set to Vpim's Vcard-Export

2008-10-01T19:12:00.007+02:00

If you are using Vpim to export Vcards and ever need to include a character set on your lines in the generated Vcard-file, here's how to do it:

# open up Vpim's DirectoryInfo::Field class
module Vpim
  class DirectoryInfo
    class Field
      class << self
        alias_method :orig_create, :create
        
        # we overwrite Field.create for setting the CHARSET
        def create(name, value='', params={})
          # specify the lines you don't want to add a charset to
          lines_to_ignore = %w(BEGIN END VERSION)
          params.merge!({'CHARSET' => 'ISO-8859-1'}) unless lines_to_ignore.include? name
          orig_create(name, value, params)
        end
      end
        
    end
  end
end

Ruby Syntax Highlighting on Web Pages

2008-10-01T17:52:00.025+02:00

Here's a fast and easy way to do syntax highlighting on web pages (e.g. blogs). This works for ruby and html/xml:

First Install Jamis Buck's syntax gem

gem install syntax

Then create a file ruby2html.rb with the following content

require 'rubygems'
require 'syntax/convertors/html'

#create a new ruby2Html-converter and convert clipboard-content to html
converter = Syntax::Convertors::HTML.for_syntax "ruby"
html_code = converter.convert(IO.popen('pbpaste', 'r+').read, false)

#wrap the code in a pre-tag with class 'ruby'
html_code = ["<pre class='ruby'>", html_code, "</pre>"].join

#output the generated html-code to the console
puts html_code

#write the html_code back to the clipboard
IO.popen('pbcopy', 'r+').puts html_code

Then just copy the content of the clipboard into your blog or webpage.

Warning: the code uses the cmd-line tools 'popen' and 'pbcopy' to access the clipboard. Those tools are MacOSX specific. If you're on Linux see this blog post, something similar for windows users is describe here.

Add this css declarations to the header of your web page (change them to fit your need):

pre {
    background-color: #f1f1f3;
    color: #112;
    padding: 10px;
    font-size: 1.1em;
    overflow: auto;
    margin: 4px 0px;
    width: 95%;
}

/* Syntax highlighting */
.ruby .normal {}
.ruby .comment { color: #6a6969; font-style: italic; }
.ruby .keyword { color: #7f2a53; font-weight: bold; }
.ruby .method { color: #077; }
.ruby .class { color: #683c2b; font-weight: bold;}
.ruby .module { color: #050; }
.ruby .punct { color: #000; font-weight: bold; }
.ruby .symbol { color: #000; }
.ruby .string { color: #2a9a67; background: #e8f5f5; }
.ruby .char { color: #F07; }
.ruby .ident { color: #004; }
.ruby .constant { color: #07F; }
.ruby .regex { color: #B66; background: #FEF; }
.ruby .number { color: #F99; }
.ruby .attribute { color: #7BB; }
.ruby .global { color: #7FB; }
.ruby .expr { color: #227; }
.ruby .escape { color: #277; }

If you need syntax highlighting for XML or HTML you can modify the ruby2html.rb to use the XML-Converter of the syntax gem.