Module: Sinatra::LinkHeader

Relationships & Source Files
Defined in:	sinatra-contrib/lib/sinatra/link_header.rb

Overview

Sinatra::LinkHeader adds a set of helper methods to generate link HTML tags and their corresponding Link HTTP headers.

=== Usage

Once you had set up the helpers in your application (see below), you will be able to call the following methods from inside your route handlers, filters and templates:

#prefetch:: Sets the Link HTTP headers and returns HTML tags to prefetch the given resources.

#stylesheet:: Sets the Link HTTP headers and returns HTML tags to use the given stylesheets.

#link:: Sets the Link HTTP headers and returns the corresponding HTML tags for the given resources.

#link_headers:: Returns the corresponding HTML tags for the current Link HTTP headers.

==== Classic Application

In a classic application simply require the helpers, and start using them:

require "sinatra"
require "sinatra/link_header"

# The rest of your classic application code goes here...

==== Modular Application

In a modular application you need to require the helpers, and then tell the application you will use them:

require "sinatra/base"
require "sinatra/link_header"

class MyApp < Sinatra::Base
  helpers Sinatra::LinkHeader

  # The rest of your modular application code goes here...
end

Class Method Summary

.registered(_base)

Instance Method Summary

#link(*urls)

Sets Link HTTP header and returns corresponding HTML tags.
#link_headers

Takes the current value of th Link header(s) and generates HTML tags from it.
#prefetch(*urls)

Sets Link HTTP header and returns HTML tags for telling the browser to prefetch given resources (only supported by Opera and Firefox at the moment).
#stylesheet(*urls)

Sets Link HTTP header and returns HTML tags for using stylesheets.

Class Method Details

.registered(_base)

[ GitHub ]

# File 'sinatra-contrib/lib/sinatra/link_header.rb', line 128


def self.registered(_base)
  puts "WARNING: #{self} is a helpers module, not an extension."
end

Instance Method Details

#link(*urls)

Sets Link HTTP header and returns corresponding HTML tags.

Example:

# Sets header: # Link: ; rel="next" # Returns String: # '' link '/foo', :rel => :next

# Multiple URLs link :stylesheet, '/a.css', '/b.css'

[ GitHub ]

# File 'sinatra-contrib/lib/sinatra/link_header.rb', line 83


def link(*urls)
  opts          = urls.last.respond_to?(:to_hash) ? urls.pop : {}
  opts[:rel]    = urls.shift unless urls.first.respond_to? :to_str
  options       = opts.map { |k, v| " #{k}=#{v.to_s.inspect}" }
  html_pattern  = "<link href=\"%s\"#{options.join} />"
  http_pattern  = ['<%s>', *options].join ';'
  link          = (response['Link'] ||= '')

  link = response['Link'] = +link

  urls.map do |url|
    link << "," unless link.empty?
    link << (http_pattern % url)
    html_pattern % url
  end.join
end

#link_headers

Takes the current value of th Link header(s) and generates HTML tags from it.

Example:

get '/' do # You can of course use fancy helpers like #link, #stylesheet # or #prefetch response["Link"] = '; rel="next"' haml :some_page end

END

@@ layout %head= link_headers %body= yield

[ GitHub ]

# File 'sinatra-contrib/lib/sinatra/link_header.rb', line 118


def link_headers
  yield if block_given?
  return '' unless response.include? 'Link'

  response['Link'].split(",").map do |line|
    url, *opts = line.split(';').map(&:strip)
    "<link href=\"#{url[1..-2]}\" #{opts.join ' '} />"
  end.join
end

#prefetch(*urls)

Sets Link HTTP header and returns HTML tags for telling the browser to prefetch given resources (only supported by Opera and Firefox at the moment).

[ GitHub ]

# File 'sinatra-contrib/lib/sinatra/link_header.rb', line 58


def prefetch(*urls)
  link(:prefetch, *urls)
end

#stylesheet(*urls)

Sets Link HTTP header and returns HTML tags for using stylesheets.

[ GitHub ]

# File 'sinatra-contrib/lib/sinatra/link_header.rb', line 64


def stylesheet(*urls)
  urls << {} unless urls.last.respond_to? :to_hash
  urls.last[:type] ||= mime_type(:css)
  link(:stylesheet, *urls)
end