Class: Yarn::AbstractHandler

Inherits:
Object
  • Object
show all
Includes:
ErrorPage, Logging
Defined in:
lib/yarn/abstract_handler.rb

Overview

Base class for the handler classes. Built using the Template Method design pattern.

Direct Known Subclasses

RackHandler, RequestHandler

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from ErrorPage

#serve_404_page, #serve_500_page

Methods included from Logging

#debug, #log, #output, #timestamp

Constructor Details

#initialize ⇒ AbstractHandler

Returns a new instance of AbstractHandler.



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# File 'lib/yarn/abstract_handler.rb', line 21

def initialize
  @parser = Parser.new
  @response = Response.new
end

Instance Attribute Details

#parser ⇒ Object

Returns the value of attribute parser.



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# File 'lib/yarn/abstract_handler.rb', line 19

def parser
  @parser
end

#request ⇒ Object

Returns the value of attribute request.



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# File 'lib/yarn/abstract_handler.rb', line 19

def request
  @request
end

#response ⇒ Object

Returns the value of attribute response.



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# File 'lib/yarn/abstract_handler.rb', line 19

def response
  @response
end

#session ⇒ Object

Returns the value of attribute session.



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# File 'lib/yarn/abstract_handler.rb', line 19

def session
  @session
end

Instance Method Details

#client_address ⇒ Object

Proxy for the clients address.



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# File 'lib/yarn/abstract_handler.rb', line 131

def client_address
  begin
    @session.peeraddr(:numeric)[2] if @session
  rescue Errno::ENOTCONN
    return ""
  end
end

#extract_path ⇒ Object

Extracts the path from the parsed request



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# File 'lib/yarn/abstract_handler.rb', line 112

def extract_path
  path = @request[:uri][:path].to_s
  if path[0] == "/" && path != "/"
    path = path[1..-1] 
  end
  path.gsub(/%20/, " ").strip
end

#parse_request ⇒ Object

Invokes the parser upon the request

Raises:



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# File 'lib/yarn/abstract_handler.rb', line 49

def parse_request
  raw_request = read_request
  raise EmptyRequestError if raw_request.empty?

  begin
    @request = @parser.run raw_request
  rescue Parslet::ParseFailed => e
    @response.status = 400
    debug "Parse failed: #{@request}"
  end
end

#post_body ⇒ Object

Proxy to getting the request body.



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# File 'lib/yarn/abstract_handler.rb', line 121

def post_body
  @request ? @request[:body].to_s : ""
end

#prepare_response ⇒ Object

Only implemented in the actual handler classes.



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# File 'lib/yarn/abstract_handler.rb', line 62

def prepare_response
end

#read_request ⇒ Object

Reads the request from the socket. If a Content-Length header is given, that means there is an accompanying request body. The body is read according to the set Content-Length.



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# File 'lib/yarn/abstract_handler.rb', line 83

def read_request
  input = []
  while (line = @session.gets) do
    length = line.gsub(/\D/,"") if line =~ /Content-Length/
      if line == "\r\n"
        input << line
        input << @session.read(length.to_i) if length
        break
      else
        input << line
      end
  end

  debug "Done reading request"
  input.join
end

#request_path ⇒ Object

Proxy for getting the request path.



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# File 'lib/yarn/abstract_handler.rb', line 126

def request_path
  @request[:uri][:path] if @request
end

#return_response ⇒ Object

returns the reqponse by writing it to the socket.



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# File 'lib/yarn/abstract_handler.rb', line 66

def return_response
  begin
    @session.puts "HTTP/1.1 #{@response.status} #{STATUS_CODES[@response.status]}"
    @session.puts @response.headers.map { |k,v| "#{k}: #{v}" }
    @session.puts ""

    @response.body.each do |line|
      @session.puts line
    end
  rescue Exception => exception
    log "An error occured returning the response to the client"
  end
end

#run(session) ⇒ Object

The template method which drives the handlers. Starts by setting common headers and parses the request, prepares the response, returns it to the client, and closes the connection.



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# File 'lib/yarn/abstract_handler.rb', line 30

def run(session)
  set_common_headers
  @session = session
  begin
    parse_request
    debug "Request parsed, path: #{request_path}"
    prepare_response
    debug "Response prepared: #{@response.status}"
    return_response
    log "#{STATUS_CODES[@response.status]} #{client_address} #{request_path}"
  rescue EmptyRequestError
    log "Empty request from #{client_address}"
  ensure
    @session.close
    debug "Connection closed"
  end
end

#set_common_headers ⇒ Object

Sets common headers like server name and date.



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# File 'lib/yarn/abstract_handler.rb', line 101

def set_common_headers
  @response.headers[:Server] = "Yarn webserver v#{VERSION}"

  # HTTP date format: Fri, 31 Dec 1999 23:59:59 GMT
  time ||= DateTime.now.new_offset(0)
  @response.headers[:Date] = time.strftime("%a, %d %b %Y %H:%M:%S GMT")
  # Close connection header ( until support for persistent connections )
  @response.headers[:Connection] = "Close"
end