Category Archives: RubyOnRails

On Amazon S3 you can access your files through different URL’s, depending on which suites best your requirements:

• Your bucket as “folder”: http://s3.amazonaws.com/your-bucket/your-file.txt
• As subdomain: http://your-bucket.s3.amazonaws.com/your-file.txt
• With a CNAME on your own domain: http://images.my-domain.com/your-file.jpg

How to setup a CNAME with Amazon S3 is explained pretty well here.

I had however some trouble setting up the correct URL to this CNAME in Paperclip, the popular Rails gem for handling file uploads.

This is the final configuration which is working for me is:

has_attached_file :image,
      :storage => 's3',
      :s3_credentials => { :access_key_id => ENV['S3_KEY'], :secret_access_key => ENV['S3_SECRET'] },
      :s3_headers => { 'Expires' => 1.year.from_now.httpdate },
      :s3_host_alias => 'subdomain.my-domain.com',
      :bucket => 'subdomain.my-domain.com',
      :url => ":s3_alias_url",
      :path => "/images/:class/:id_:basename.:style.:extension",
      :styles => { :thumb  => '70x70#',
      							:medium => '350x350',
      							:original => '1000x1000>' },
      :default_style => :original,
      :convert_options => { :all => '-strip -trim' }

I’m using Heroku as hosting service, therefore I save the S3 key and secret in an environment variable.
:s3_host_alias is the CNAME which you need to configure for your domain. The exact same string needs to be as well the name of the bucket.
Finally just assign “:s3_alias_url” to :url. Without that the URL won’t be generated correctly. You would end up with something like “http://s3.amazonaws.com/your-file.txt” which is missing entirely the bucket name and would not load the file.
Note that for this configuration it’s not necessary to define :bucket.

Today I tried to use Heroku on Ubuntu / RVM for a Rails 3 test app. I ran into a similar problem like I had yesterday with OpenSSL.

After installing the Heroku gem:

gem install heroku

and running the command for create a new app

heroku create

I got this error

/home/siebel/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require': no such file to load -- readline (LoadError)
	from /home/siebel/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
	from /home/siebel/.rvm/gems/ruby-1.8.7-p249/gems/heroku-1.9.10/lib/heroku/commands/app.rb:1
	from /home/siebel/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
	from /home/siebel/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
	from /home/siebel/.rvm/gems/ruby-1.8.7-p249/gems/heroku-1.9.10/lib/heroku/command.rb:5
	from /home/siebel/.rvm/gems/ruby-1.8.7-p249/gems/heroku-1.9.10/lib/heroku/command.rb:5:in `each'
	from /home/siebel/.rvm/gems/ruby-1.8.7-p249/gems/heroku-1.9.10/lib/heroku/command.rb:5
	from /home/siebel/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
	from /home/siebel/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
	from /home/siebel/.rvm/gems/ruby-1.8.7-p249/gems/heroku-1.9.10/bin/heroku:7
	from /home/siebel/.rvm/gems/ruby-1.8.7-p249/bin/heroku:19:in `load'
	from /home/siebel/.rvm/gems/ruby-1.8.7-p249/bin/heroku:19

Now, the first line looks darn familiar and so does the solution:

First install libreadline-dev:

sudo apt-get install libreadline-dev

Then cd into

~/.rvm/src/ruby-1.8.7-p249/ext/readline

and build the extension:

ruby extconf.rb
make
make install

That’s it… heroku should run after that without problems.

Today I noticed that List Kung Fu displays the mobile version of the list page when I browse there with regular desktop Internet Explorer. Surfing to the same page with Firefox or Opera on the same machine worked fine and just returned the regular HTML page.

So what’s up?

Simple… Internet Explorer sends a really funny accepts header, none of the formats actually is text/html. Thus HTML is covered with an implicit */*. That’s not awesome (in good IE manner), but not really a problem. A problem it just becomes with something like this in your controller action:

      respond_to do |format|
        format.mobile
        format.html
      end

Since Internet Explorer doesn’t send an explicit accept for text/html, Rails would just default to the first format, in above case format.mobile and then correctly return the mobile version of the view. The fix is easy. Just move format.html to the first position:

      respond_to do |format|
        format.html
        format.mobile
      end

Now */* would default to format.html.