class Rack::Backbone

Backbone CDN script tags and fallback in one neat package.

Constants

BACKBONE_FILE_NAME

Current file name of fallback.

BACKBONE_SOURCE_MAP

Fallback source map file name without version. Because the main script doesn’t call a versioned file.

BACKBONE_VERSION

the version of Backbone it supports.

BACKBONE_VERSION_DATE

This is the release date of the Backbone file, it makes an easy “Last-Modified” date for setting the headers around caching. @todo remember to change Last-Modified with each release!

DEFAULT_OPTIONS

Default options hash for the middleware.

FALLBACK_BOTTOM

Bottom half of the fallback script.

FALLBACK_TOP

This javascript checks if the Backbone object has loaded. If not, that most likely means the CDN is unreachable, so it uses the local minified Backbone. It’s the top half, it gets pieced together elsewhere.

VERSION

the version of this library

Public Class Methods

cdn( env, options={} ) click to toggle source

@param [Hash] env The rack env hash. @option options [Symbol] organisation Choose which CDN to use, either :jsdelivr, or :cloudflare (the default). This will override anything set via the ‘use` statement. Pass in `false` to force use of the local Backbonejs script. `nil` will force choosing the default CDN. @option options [TrueClass] :debug Pass `true` to get the unminified version of the script from the CDN. @return [String] The HTML script tags to get the CDN.

# File lib/rack/backbone.rb, line 57
def self.cdn( env, options={}  )
  if env.nil? || env.has_key?(:organisation)
    fail ArgumentError, "The Rack::Backbone.cdn method needs the Rack environment passed to it, or at the very least, an empty hash."
  end
      
  debug = options.fetch :debug, false

  organisation =  options[:organisation]
  if organisation.nil?
    organisation = 
      env["rack.backbone.organisation"] ||
      :media_temple
  end

  unless organisation == false
    script_src = case organisation
      when :cloudflare
        CDN::CLOUDFLARE
      when :jsdelivr
        CDN::JSDELIVR
      else
        CDN::CLOUDFLARE
    end

    script_src = "#{script_src[0..-8]}.js" if debug

    %Q!<script src='#{script_src}'></script>\n#{FALLBACK_TOP.chomp}#{env["rack.backbone.http_path"]}#{FALLBACK_BOTTOM}!
  else
    "<script src='#{env["rack.backbone.http_path"]}'></script>"
  end

end
new( app, options={} ) click to toggle source

@param [#call] app @param [Hash] options @option options [String] :http_path If you wish the Backbone fallback route to be “/js/backbone-1.9.1.min.js” (or whichever version this is at) then do nothing, that’s the default. If you want the path to be “/assets/javascripts/backbone-1.9.1.min.js” then pass in ‘:http_path => “/assets/javascripts”. @option options [Symbol] :organisation see {Rack::Backbone.cdn} @example

# The default:
use Rack::Backbone

# With a default organisation:
use Rack::Backbone, :organisation => :cloudflare
# File lib/rack/backbone.rb, line 102
def initialize( app, options={} )
  @app, @options  = app, DEFAULT_OPTIONS.merge(options)
  @http_path_to_backbone = ::File.join @options[:http_path], BACKBONE_FILE_NAME
  @http_path_to_source_map = ::File.join @options[:http_path], BACKBONE_SOURCE_MAP
  @organisation = options.fetch :organisation, :media_temple
end

Public Instance Methods

_call( env ) click to toggle source

For thread safety @param (see call)

# File lib/rack/backbone.rb, line 118
def _call( env )
  request = Rack::Request.new(env.dup)
  env.merge! "rack.backbone.organisation" => @organisation
  env.merge! "rack.backbone.http_path" => @http_path_to_backbone
  if request.path_info == @http_path_to_backbone
    response = Rack::Response.new
    # for caching
    response.headers.merge! caching_headers( BACKBONE_FILE_NAME, BACKBONE_VERSION_DATE)

    # There's no need to test if the IF_MODIFIED_SINCE against the release date because the header will only be passed if the file was previously accessed by the requester, and the file is never updated. If it is updated then it is accessed by a different path.
    if request.env['HTTP_IF_MODIFIED_SINCE']
      response.status = 304
    else
      response.status = 200
      response.write ::File.read( ::File.expand_path "../../../vendor/assets/javascripts/libs/backbone/#{BACKBONE_VERSION}/#{BACKBONE_FILE_NAME}", __FILE__)
    end
    response.finish
  elsif request.path_info == @http_path_to_source_map
    response = Rack::Response.new
    # No need for caching with the source map
    response.status = 200
    response.write ::File.read( ::File.expand_path "../../../vendor/assets/javascripts/libs/backbone/#{BACKBONE_VERSION}/#{BACKBONE_SOURCE_MAP}", __FILE__)
    response.finish
  else
    @app.call(env)
  end
end
call( env ) click to toggle source

@param [Hash] env Rack request environment hash.

# File lib/rack/backbone.rb, line 111
def call( env )
  dup._call env
end