Add Rack::HostMeta

README.rdoc

@@ -41,6 +41,7 @@ interface:
 * Rack::Backstage - Returns content of specified file if it exists, which makes
   it convenient for putting up maintenance pages.
 * Rack::Format - Adds a format extension at the end of the URI when there is none, corresponding to the mime-type given in the Accept HTTP header.
+* Rack::HostMeta - Configures /host-meta using a block
 
 === Use
 

lib/rack/contrib/host_meta.rb

@@ -0,0 +1,41 @@
+module Rack
+
+  # Rack middleware implementing the IETF draft: "Host Metadata for the Web"
+  #
+  # Usage:
+  #  use Rack::HostMeta do
+  #    register :uri => '/robots.txt', :rel => 'robots'
+  #    register :uri => '/w3c/p3p.xml', :rel => 'privacy', :type => 'application/p3p.xml'
+  #  end
+  #
+  # See also: http://tools.ietf.org/html/draft-nottingham-site-meta
+  #
+  # TODO:
+  #   Accept POST operations allowing downstream services to register themselves
+  #
+  class HostMeta
+    def initialize(app, &block)
+      @app = app
+      @links = []
+      instance_eval(&block)
+      @response = @links.join("\n")
+    end
+
+    def call(env)
+      if env['PATH_INFO'] == '/host-meta'
+        [200, {'Content-Type' => 'application/host-meta'}, [@response]]
+      else
+        @app.call(env)
+      end
+    end
+
+    protected
+
+    def register(config)
+      link = "Link: <#{config[:uri]}>;"
+      link += " rel=\"#{config[:rel]}\"" if config[:rel]
+      link += " type=\"#{config[:type]}\"" if config[:type]
+      @links << link
+    end
+  end
+end

test/spec_rack_host_meta.rb

@@ -0,0 +1,43 @@
+require 'test/spec'
+require 'rack/mock'
+require 'rack/contrib/host_meta'
+require 'rack/contrib/not_found'
+
+context "Rack::HostMeta" do
+
+  setup do
+    app = Rack::Builder.new do
+      use Rack::Lint
+      use Rack::ContentLength
+      use Rack::HostMeta do
+        register :uri => '/robots.txt', :rel => 'robots'
+        register :uri => '/w3c/p3p.xml', :rel => 'privacy', :type => 'application/p3p.xml'
+      end
+      run Rack::NotFound.new('test/404.html')
+    end
+    @response = Rack::MockRequest.new(app).get('/host-meta')
+  end
+
+  specify "should respond to /host-meta" do
+    @response.status.should.equal 200
+  end
+
+  specify "should respond with the correct media type" do
+    @response['Content-Type'].should.equal 'application/host-meta'
+  end
+
+  specify "should include a Link entry for each item in the config block" do
+    @response.body.should.match(/Link:\s*<\/robots.txt>;.*\n/)
+    @response.body.should.match(/Link:\s*<\/w3c\/p3p.xml>;.*/)
+  end
+
+  specify "should include a rel attribute for each Link entry where specified" do
+    @response.body.should.match(/rel="robots"/)
+    @response.body.should.match(/rel="privacy"/)
+  end
+
+  specify "should include a type attribute for each Link entry where specified" do
+    @response.body.should.match(/Link:\s*<\/w3c\/p3p.xml>;.*type.*application\/p3p.xml/)
+  end
+
+end