// get started with ubuntu 7.1
// e.g. on a new slice from http://slicehost.com !

# 1) make yrself a user and stop being root

# 2) main web stack + ruby
sudo aptitude install -y make screen
sudo aptitude install -y apache2 php5 mysql-server
sudo aptitude install -y subversion postfix
sudo aptitude install -y ruby1.8 ruby1.8-dev rubygems irb
sudo aptitude install -y imagemagick librmagick-ruby1.8 librmagick-ruby-doc libfreetype6-dev xml-core

# 3) gemz
# rubygems appears to be broken as hell. 
# gem update --system does squat
# had to manually d/l rubygems 1.0.1, ruby setup.rb
wget http://rubyforge.org/frs/download.php/29548/rubygems-1.0.1.tgz
tar xzvf rubygems-1.0.1.tgz
cd rubygems-1.0.1
sudo ruby setup.rb
sudo gem install rails mongrel merb map_by_method

// Just throw this at the bottom of your application.js and you’re good to go: all jQuery ajax requests will trigger the wants.js block of your respond_to declaration, exactly like you’d expect. Enjoy.
// via: http://ozmm.org/posts/jquery_and_respond_to.html

jQuery.ajaxSetup({ ‘beforeSend’: function(xhr) {xhr.setRequestHeader(“Accept”, “text/javascript”)} })

Essential for degradable javascript, when one never knows if a view or partial is being called via XmlHttpRequest or not. Throw the below code in your ApplicationController (application.rb)

More info in this blog post

def render(*args)
  	args.first[:layout] = false if request.xhr? and args.first[:layout].nil?
	super
end

Fed up of empty wrapper html tags when content isn't there? Then use this Rails helper...

  def tag_unless_empty(html_tag, options = {}, &block)
    html_options = options.stringify_keys

    if block_given?
      content = capture(&block)
      unless content.strip.empty?
        concat(tag(html_tag, html_options, true), block.binding)
        concat(content, block.binding)
        concat("</#{html_tag}>", block.binding)
      end
    end
  end

Example:

<% tag_unless_empty :div, :class => "css_class" do %>
   <%# Nothing actually rendered here %>
   <%# or here %>
<% end %>

produces nothing, whereas

<% tag_unless_empty :div, :class => "css_class" do %>
   <%= 'Something rendered here' %>
<% end %>

produces

<div class="css_class">Something rendered here</div>

A oneline helper I put in all of my apps. Looks for HTTP headers that signal you're being called via an XmlHttpRequest. I use it for instant degradable AJAX by rendering a template if it's as usual but just rendering a partial if they just want that part!

  def ajax_request?
    request.env['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest' || params[:ajax]  # params[:ajax] for safe-keeping, FIXME if it works w/ all browsers
  end

// Code To Upload an image to a database and then update its contents.

# Create an ew classified and attach an image with it.
def create
  image_types = ["image/jpeg", "image/pjpeg", "image/gif","image/png", "image/x-png"]
  @categories = Category.find(:all)
  @classified = Classified.new(params[:classified])
  @classified.user = session[:user]
  unless params[:classified][:picture].blank?
    if (image_types.include?params[:classified][:picture].content_type.chomp)
      @classified.picture = params[:classified][:picture].read
    else
      @classified.errors.add(:picture,  "Photo doesn't seem to be JPG, GIF, or PNG. please ensure it is a valid image file.")
      render :action => 'new'
      return
    end
  end

  if @classified.save
    redirect_to :action => 'list'
  else 
    render :action => 'new'
  end
end


# Update Method So user can change the image associated with their classified
def update
  image_types = ["image/jpeg", "image/pjpeg", "image/gif", "image/png", "image/x-png"]
  @classified = Classified.find(params[:id])
  @categories = Category.find(:all)
  
  if @classified.update_attributes(params[:classified])
    unless params[:classified][:picture].blank?
      if (image_types.include?params[:classified][:picture].content_type.chomp)
        @classified.picture = params[:classified][:picture].read
      else
        @classified.errors.add(:picture, " doesn't seem to be JPG, GIF, or PNG. please ensure it is a valid image file.")
        render :action => 'edit'
        return
      end
    end
    
    flash[:notice] = 'Classified was successfully updated.'
    redirect_to :action => 'show', :id => @classified
  else
    render :action => 'edit'
  end
end

# environment.rb

module FileColumn
  class PermanentUploadedFile    
    alias_method :orig_move_from, :move_from
    def move_from(local_dir, just_uploaded)
      FileUtils.rm_rf @dir
      
      part_it_options = @instance.class.acts_as_partitioned_id_options
      partition_length = part_it_options[:digits] / part_it_options[:partitions]
      #last_partition = @dir[-partition_length.to_i..-1]
      the_rest = @dir[0...-partition_length.to_i]
      FileUtils.mkpath the_rest
      
      FileUtils.mv local_dir, @dir
      @just_uploaded = just_uploaded
    end
    
    private
    alias_method :orig_relative_path_prefix, :relative_path_prefix
    def relative_path_prefix
      raise RuntimeError.new("Trying to access file_column, but primary key got lost.") if @instance.partitioned_id.to_s.empty?
      @instance.partitioned_id.to_s
    end
  end
end

# environment.rb

module FileColumn
  class PermanentUploadedFile    
    alias_method :orig_move_from, :move_from
    def move_from(local_dir, just_uploaded)
      FileUtils.rm_rf @dir
      
      part_it_options = @instance.class.acts_as_partitioned_id_options
      partition_length = part_it_options[:digits] / part_it_options[:partitions]
      #last_partition = @dir[-partition_length.to_i..-1]
      the_rest = @dir[0...-partition_length.to_i]
      FileUtils.mkpath the_rest
      
      FileUtils.mv local_dir, @dir
      @just_uploaded = just_uploaded
    end
    
    private
    alias_method :orig_relative_path_prefix, :relative_path_prefix
    def relative_path_prefix
      raise RuntimeError.new("Trying to access file_column, but primary key got lost.") if @instance.partitioned_id.to_s.empty?
      @instance.partitioned_id.to_s
    end
  end
end

# environment.rb

module FileColumn
  class PermanentUploadedFile    
    alias_method :orig_move_from, :move_from
    def move_from(local_dir, just_uploaded)
      FileUtils.rm_rf @dir
      
      part_it_options = @instance.class.acts_as_partitioned_id_options
      partition_length = part_it_options[:digits] / part_it_options[:partitions]
      #last_partition = @dir[-partition_length.to_i..-1]
      the_rest = @dir[0...-partition_length.to_i]
      FileUtils.mkpath the_rest
      
      FileUtils.mv local_dir, @dir
      @just_uploaded = just_uploaded
    end
    
    private
    alias_method :orig_relative_path_prefix, :relative_path_prefix
    def relative_path_prefix
      raise RuntimeError.new("Trying to access file_column, but primary key got lost.") if @instance.partitioned_id.to_s.empty?
      @instance.partitioned_id.to_s
    end
  end
end

// I use this for checking out a new rails project

svn checkout http://studicious.com/svn/trunk %1
svn remove log/*
svn commit -m "Removed log files"
svn propset svn:ignore "*.log" log/
svn update log/
svn commit -m "Ignoring log files"
svn remove tmp/*
svn propset svn:ignore "*" tmp/
svn update tmp/
svn commit -m "Ignoring temp folder"