Class: ExperellaProxy::Connection

Inherits:
EventMachine::Connection
  • Object
show all
Includes:
Globals
Defined in:
lib/experella-proxy/connection.rb

Overview

The proxies TCP Connection to the client

Responsible for parsing and buffering the clients http requests, connecting to the backend server, sending data to the backend server and returning responses to the client.

See EventMachine::Connection documentation for more information

See Also:

Instance Method Summary collapse

Methods included from Globals

#config, #connection_manager, #event, #logger

Instance Method Details

#close ⇒ Object

calls EventMachine close_connection_after_writing method with 1 tick delay waits 1 tick to make sure reactor i/o does not have unnecessary loop delay



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# File 'lib/experella-proxy/connection.rb', line 90

def close
  @unbound = true
  EM.next_tick(method(:close_connection_after_writing))
  event(:connection_close, :signature => @signature, :msec => msec)
end

#connect_backendserver(backend) ⇒ Object

Connects self to a BackendServer object

Any request mangling configured in BackendServer#mangle will be done here

Method provides additional support for BackendServer’s named “web”. Host and Port will be determined through the Request instead of BackendServer settings.



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# File 'lib/experella-proxy/connection.rb', line 104

def connect_backendserver(backend)
  @backend = backend
  connection_manager.free_connection(self)
  # mangle http headers
  mangle
  # reconstruct the request header
  get_request.reconstruct_header
  # special web support for unknown hosts
  if @backend.name.eql?("web")
    xport = get_request.header[:Host].match(/:[0-9]+/)
    if xport.nil? || xport.to_s.empty?
      xport = "80"
    else
      xport = xport.to_s.gsub(/:/, "")
    end
    xhost = get_request.header[:Host].gsub(":#{xport}", "")
    server(@backend.name, :host => xhost, :port => xport)
  else
    server(@backend.name, :host => @backend.host, :port => @backend.port)
  end
end

#connected(name) ⇒ Object

Called by backend connections when the remote TCP connection attempt completes successfully.

#on_connect block will be executed here

This method triggers the #relay_to_server method



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# File 'lib/experella-proxy/connection.rb', line 133

def connected(name)
  @on_connect.call(name) if @on_connect
  event(:connection_connected, :msec => msec, :signature => @signature.to_s, :name => name)
  relay_to_server
end

#get_request ⇒ Request

Used for accessing the connections first request

Buffered requests must not be handled before first in done



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# File 'lib/experella-proxy/connection.rb', line 144

def get_request
  @requests.first
end

#on_connect(&blk) ⇒ Object

Used to pass an optional block to the connection which will be executed when the #connected event occurs

Examples:

# called on successful backend connection
# backend is the name of the connected server
conn.on_connect do |backend|

end



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# File 'lib/experella-proxy/connection.rb', line 25

def on_connect(&blk)
  @on_connect = blk
end

#on_data(&blk) ⇒ String

Used to pass an optional block to the connection which will be executed when the #receive_data event occurs

Examples:

# modify / process request stream
# and return modified data
conn.on_data do |data|
  data
end



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# File 'lib/experella-proxy/connection.rb', line 40

def on_data(&blk)
  @on_data = blk
end

#on_finish(&blk) ⇒ Object

Used to pass an optional block to the connection which will be executed when the #unbind_backend event occurs

Examples:

# termination logic
# backend is the name of the connected server
conn.on_finish do |backend|

end



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# File 'lib/experella-proxy/connection.rb', line 70

def on_finish(&blk)
  @on_finish = blk
end

#on_response(&blk) ⇒ String

Used to pass an optional block to the connection which will be executed when the #relay_from_backend event occurs

Examples:

# modify / process response stream
# and return modified response
# backend is the name of the connected server
conn.on_response do |backend, resp|
  resp
end



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# File 'lib/experella-proxy/connection.rb', line 56

def on_response(&blk)
  @on_response = blk
end

#on_unbind(&blk) ⇒ Object

Used to pass an optional block to the connection which will be executed when the #unbind event occurs

Examples:

# called if client terminates connection
# or timeout occurs
conn.on_unbind do

end



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# File 'lib/experella-proxy/connection.rb', line 84

def on_unbind(&blk)
  @on_unbind = blk
end

#peer ⇒ Object

ip, port of the connected client



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# File 'lib/experella-proxy/connection.rb', line 210

def peer
  @peer ||= begin
    peername = get_peername
    peername ? Socket.unpack_sockaddr_in(peername).reverse : nil
  end
end

#post_init ⇒ Object

Called by the event loop immediately after the network connection has been established, and before resumption of the network loop. This method is generally not called by user code, but is called automatically by the event loop. The base-class implementation is a no-op. This is a very good place to initialize instance variables that will be used throughout the lifetime of the network connection.

This is currently used to initiate start_tls on @options enabled

See Also:



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# File 'lib/experella-proxy/connection.rb', line 231

def post_init
  if @options[:tls]
    event(:connection_tls_handshake_start, :msec => msec, :signature => @signature)
    start_tls(:private_key_file => @options[:private_key_file], :cert_chain_file => @options[:cert_chain_file], :verify_peer => false)
  end
end

#receive_data(data) ⇒ Object

Called by the EventMachine loop whenever data has been received by the network connection. It is never called by user code. #receive_data is called with a single parameter, a String containing the network protocol data, which may of course be binary.

Data gets passed to the specified #on_data block first Then data gets passed to the parser and the #relay_to_server method gets fired

On Http::Parser::Error a 400 Bad Request error send to the client and the Connection will be closed



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# File 'lib/experella-proxy/connection.rb', line 158

def receive_data(data)
  event(:connection_receive_data_start, :msec => msec, :data => data)
  data = @on_data.call(data) if @on_data
  begin
    @request_parser << data
  rescue Http::Parser::Error
    event(:connection_receive_data_parser_error, :msec => msec, :signature => @signature, :error => true)
    # on error unbind request_parser object, so additional data doesn't get parsed anymore
    #
    # assigning a string to the parser variable, will cause incoming data to get buffered
    # imho this is a better solution than adding a condition for this rare error case
    @request_parser = ""
    send_data "HTTP/1.1 400 Bad Request\r\nVia: 1.1 experella\r\nConnection: close\r\n\r\n"
    close
  end

  event(:connection_receive_data_stop, :msec => msec, :data => data)
  relay_to_server
end

#relay_from_backend(name, data) ⇒ Object

Called by Backend connections. Relays data from backend server to the client

#on_response block will be executed here



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# File 'lib/experella-proxy/connection.rb', line 185

def relay_from_backend(name, data)
  event(:connection_relay_from_backend, :msec => msec, :data => data, :name => name)
  @got_response = true
  data = @on_response.call(name, data) if @on_response
  get_request.response << data
end

#server(name, opts) ⇒ Object

Initialize a Backend connection

Can connect to host:port server address



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# File 'lib/experella-proxy/connection.rb', line 198

def server(name, opts)
  srv = EventMachine.bind_connect(opts[:bind_host], opts[:bind_port], opts[:host], opts[:port], Backend) do |c|
    c.name = name
    c.plexer = self
  end

  @server = srv
end

#sock ⇒ Object

ip, port of the local server connect



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# File 'lib/experella-proxy/connection.rb', line 241

def sock
  @sock ||= begin
    sockname = get_sockname
    sockname ? Socket.unpack_sockaddr_in(sockname).reverse : nil
  end
end

#ssl_handshake_completed ⇒ Object

Called by EventMachine when the SSL/TLS handshake has been completed, as a result of calling start_tls to initiate SSL/TLS on the connection.

This callback exists because #post_init and connection_completed are not reliable for indicating when an SSL/TLS connection is ready to have its certificate queried for.



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# File 'lib/experella-proxy/connection.rb', line 253

def ssl_handshake_completed
  event(:connection_tls_handshake_stop, :msec => msec, :signature => @signature)
end

#unbind ⇒ Object

Called by the EventMachine loop whenever the client connection is closed. The close can occur because the code intentionally closes it (using #close_connection and #close_connection_after_writing), because the remote peer closed the connection, or because of a network error.

This is used to clean up associations made to the connection object while it was open.

#on_unbind block will be executed here



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# File 'lib/experella-proxy/connection.rb', line 322

def unbind
  @unbound = true
  @on_unbind.call if @on_unbind

  event(:connection_unbind_client, :msec => msec, :signature => @signature)
  # lazy evaluated. if first is true, second would cause a nil-pointer!
  unless @requests.empty? || get_request.flushed? # what does this mean?
    # log.debug [msec, @requests.inspect]
  end
  # delete conn from queue if still queued
  connection_manager.free_connection(self)

  # reconnect backend to new connection if this has not happened already
  unless @backend.nil?
    connect_next
  end
  # terminate any unfinished backend connections
  unless @server.nil?
    @server.close_connection_after_writing
  end
end

#unbind_backend(name) ⇒ Object

Called by backend connections whenever their connection is closed. The close can occur because the code intentionally closes it (using #close_connection and #close_connection_after_writing), because the remote peer closed the connection, or because of a network error.

Therefor connection errors, reconnections and queues need to be handled here

#on_finish block will be executed here



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# File 'lib/experella-proxy/connection.rb', line 267

def unbind_backend(name)
  event(:connection_unbind_backend, :msec => msec, :signature => @signature, :response => @got_response)

  if @on_finish
    @on_finish.call(name)
  end

  @server = nil

  # if backend responded or client unbound connection (timeout probably triggers this too)
  if @got_response || @unbound
    event(:connection_unbind_backend_request_done,
          :msec => msec,
          :signature => @signature,
          :size => @requests.size, :keep_alive => get_request.keep_alive.to_s)

    unless get_request.keep_alive
      close
      event(:connection_unbind_backend_close, :msec => msec, :signature => @signature)
    end
    @requests.shift # pop first element,request is done
    @got_response = false # reset response flag

    # free backend server and connect to next conn if matching conn exists
    unless @backend.nil?
      connect_next
    end

    # check if queued requests find a matching backend
    unless @requests.empty? || @unbound
      # try to dispatch first request to backend
      dispatch_request
    end
  else
    # handle no backend response here
    event(:connection_unbind_backend_error, :msec => msec, :error => true, :error_code => 503)
    error_page = "HTTP/1.1 503 Service unavailable\r\nContent-Length: #{config.error_pages[503].length}\r\nContent-Type: text/html;charset=utf-8\r\nConnection: close\r\n\r\n"
    unless get_request.header[:http_method].eql? "HEAD"
      error_page << config.error_pages[503]
    end
    send_data error_page

    close
  end
end