gistfile1.txt

diff --git a/lib/middleware/visitor.rb b/lib/middleware/visitor.rb
new file mode 100644
index 0000000..fdfb96d
--- /dev/null
+++ b/lib/middleware/visitor.rb
@@ -0,0 +1,100 @@
+module Middleware
+  class Visitor
+    class Node < Struct.new(:id, :name)
+    end
+
+    class Edge < Struct.new(:from, :to, :name)
+    end
+
+    def initialize
+      @nodes = []
+      @edges = []
+      @edge_stack = []
+      @node_stack = []
+      @seen = {}
+    end
+
+    def accept o
+      visit o
+      nodes = @nodes.map { |node|
+        "#{node.id} [label=\"#{node.name}\"];"
+      }.join("\n")
+      edges = @edges.map { |edge|
+        "#{edge.from.id} -> #{edge.to.id} [label=\"#{edge.name}\"];"
+      }.join("\n")
+
+      "digraph \"rack middleware\" {\n
+      
+node [
+shape = \"box\"
+];
+      #{nodes}\n#{edges}\n}"
+    end
+
+    private
+
+    def visit_Rack_Mount_RouteSet o
+      named_routes = o.instance_variable_get(:@named_routes)
+      named_routes.each do |k,v|
+        @edge_stack.push "@named_routes[#{k}]"
+        visit v
+        @edge_stack.pop
+      end
+
+      routes = o.instance_variable_get(:@routes)
+      routes.each_with_index do |k,i|
+        @edge_stack.push "@routes[#{i}]"
+        visit k
+        @edge_stack.pop
+      end
+    end
+
+    def visit_Rack_Mount_Route o
+      app = o.instance_variable_get(:@app)
+      @edge_stack.push :@app
+      visit app
+      @edge_stack.pop
+    end
+
+    def visit o
+      method = "visit_#{o.class.name.gsub('::', '_')}"
+
+      return if !o.respond_to?(:call) && !respond_to?(method, true)
+
+      if @seen.key?(o)
+        unless @edge_stack.empty?
+          @edges << Edge.new(@node_stack.last, @seen[o], @edge_stack.last)
+        end
+        return
+      end
+
+      node = Node.new(o.object_id, o.class.name)
+
+      @seen[o] = node
+      @nodes << node
+
+      unless @edge_stack.empty?
+        @edges << Edge.new(@node_stack.last, node, @edge_stack.last)
+      end
+
+      @node_stack.push node
+
+      if respond_to?(method, true)
+        send(method, o)
+      else
+        generic o
+      end
+
+      @node_stack.pop
+    end
+
+    def generic o
+      o.instance_variables.each do |ivar|
+        child = o.instance_variable_get(ivar)
+        @edge_stack.push ivar
+        visit child
+        @edge_stack.pop
+      end
+    end
+  end
+end
diff --git a/lib/rack/server.rb b/lib/rack/server.rb
index 6bf8771..f4bef58 100644
--- a/lib/rack/server.rb
+++ b/lib/rack/server.rb
@@ -1,4 +1,5 @@
 require 'optparse'
+require 'middleware/visitor'
 
 module Rack
   class Server
@@ -228,6 +229,10 @@ module Rack
         end
       end
 
+      viz = Middleware::Visitor.new
+      ::File.open('/tmp/foo.dot', 'wb') { |f|
+        f.write viz.accept wrapped_app
+      }
       server.run wrapped_app, options
     end