initial version of the worlds simplest rack handler

simple_rack.rb

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+require 'rubygems'
+require 'socket'
+require 'stringio'
+require 'rack'
+require 'rack/content_length'
+require 'rack/chunked'
+require 'pp'
+
+module Rack
+  module Handler
+    class DumbServer
+      attr_accessor :app
+
+      StatusMessage = {
+        100 => 'Continue',
+        101 => 'Switching Protocols',
+        200 => 'OK',
+        201 => 'Created',
+        202 => 'Accepted',
+        203 => 'Non-Authoritative Information',
+        204 => 'No Content',
+        205 => 'Reset Content',
+        206 => 'Partial Content',
+        300 => 'Multiple Choices',
+        301 => 'Moved Permanently',
+        302 => 'Found',
+        303 => 'See Other',
+        304 => 'Not Modified',
+        305 => 'Use Proxy',
+        307 => 'Temporary Redirect',
+        400 => 'Bad Request',
+        401 => 'Unauthorized',
+        402 => 'Payment Required',
+        403 => 'Forbidden',
+        404 => 'Not Found',
+        405 => 'Method Not Allowed',
+        406 => 'Not Acceptable',
+        407 => 'Proxy Authentication Required',
+        408 => 'Request Timeout',
+        409 => 'Conflict',
+        410 => 'Gone',
+        411 => 'Length Required',
+        412 => 'Precondition Failed',
+        413 => 'Request Entity Too Large',
+        414 => 'Request-URI Too Large',
+        415 => 'Unsupported Media Type',
+        416 => 'Request Range Not Satisfiable',
+        417 => 'Expectation Failed',
+        500 => 'Internal Server Error',
+        501 => 'Not Implemented',
+        502 => 'Bad Gateway',
+        503 => 'Service Unavailable',
+        504 => 'Gateway Timeout',
+        505 => 'HTTP Version Not Supported'
+      }
+
+      def self.run(app, options=nil)
+        new(app).listen
+      end
+
+      def initialize(app)
+        @app = app
+      end
+
+      def listen
+        log 'Starting server on 0.0.0.0:8089'
+        server = TCPServer.new('0.0.0.0', 8089)
+
+        loop do
+          socket = server.accept
+          socket.sync = true
+          log "#{socket.peeraddr[2]} (#{socket.peeraddr[3]})"
+          begin
+
+            req = {}
+            request = socket.gets
+            method, path, version = request.split(" ")
+            req["REQUEST_METHOD"] = method
+            info, query = path.split("?")
+            req["PATH_INFO"] = info
+            req["QUERY_STRING"] = query
+            while (line = socket.gets)
+              line.strip!
+              break if line.size == 0
+              key, val = line.split(": ")
+              req[key] = val
+            end
+            pp req
+
+            body = ''
+            if (len = req['Content-Length']) && ["POST", "PUT"].member?(method)
+              body = socket.read(len)
+            end
+
+            process_request(req, body, socket)
+
+            puts "DONE"
+          ensure
+            # no matter what we have to put this thread on the bad list
+            socket.close if not socket.closed?
+          end
+        end
+      end
+
+      def log(message)
+        puts message
+      end
+
+      def status_message(code)
+        StatusMessage[code]
+      end
+
+      def process_request(request, input_body, socket)
+        env = {}.replace(request)
+        env.delete "HTTP_CONTENT_TYPE"
+        env.delete "HTTP_CONTENT_LENGTH"
+        env["HTTP_VERSION"] ||= env["SERVER_PROTOCOL"]
+        env["PATH_INFO"] = env["REQUEST_PATH"]
+        env["QUERY_STRING"] ||= ""
+        env["SCRIPT_NAME"] = ""
+
+        rack_input = StringIO.new(input_body)
+        rack_input.set_encoding(Encoding::BINARY) if rack_input.respond_to?(:set_encoding)
+
+        env.update({"rack.version" => [1,0],
+                     "rack.input" => rack_input,
+                     "rack.errors" => $stderr,
+                     "rack.multithread" => true,
+                     "rack.multiprocess" => true,
+                     "rack.run_once" => false,
+
+                     "rack.url_scheme" => ["yes", "on", "1"].include?(env["HTTPS"]) ? "https" : "http"
+                   })
+        status, headers, body = app.call(env)
+        begin
+          socket.write("HTTP/1.1 #{status} #{status_message(status)}\r\n")
+          headers.each do |k, vs|
+            vs.split("\n").each { |v| socket.write("#{k}: #{v}\r\n")}
+          end
+          socket.write("\r\n")
+          body.each {|s| socket.write(s)}
+        ensure
+          body.close if body.respond_to? :close
+        end
+      end
+    end
+  end
+end
+
+
+class HelloWorld
+  def call(env)
+    [200, {"Content-Type" => "text/html"}, ["Hello world!"]]
+  end
+end
+
+Rack::Handler::DumbServer.run HelloWorld.new