Class: EventMachine::Protocols::PostgresConnection

Inherits:
Connection
  • Object
show all
Includes:
PostgresPR
Defined in:
lib/postgres_connection.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ PostgresConnection

Returns a new instance of PostgresConnection.



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# File 'lib/postgres_connection.rb', line 33

def initialize
  @data = ""
  @params = {}
  @connected = false
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/postgres_connection.rb', line 63

def close
  close_connection
end

#closed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/postgres_connection.rb', line 67

def closed?
  !@connected
end

#connect(db, user, psw = nil) ⇒ Object 



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# File 'lib/postgres_connection.rb', line 82

def connect(db, user, psw=nil)
  d = EM::DefaultDeferrable.new
  d.timeout 15

  if @pending_query || @pending_conn
    d.fail "Operation already in progress"
  else
    @pending_conn = d
    prms = {"user"=>user, "database"=>db}
    @user = user
    if psw
      @password = psw
      #prms["password"] = psw
    end
    send_data PostgresPR::StartupMessage.new( 3 << 16, prms ).dump
  end

  d
end

#dispatch_conn_message(msg) ⇒ Object

Cloned and modified from the postgres-pr.



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# File 'lib/postgres_connection.rb', line 141

def dispatch_conn_message(msg)
  case msg
  when AuthentificationClearTextPassword
    raise ArgumentError, "no password specified" if @password.nil?
    send_data PasswordMessage.new(@password).dump

  when AuthentificationCryptPassword
    raise ArgumentError, "no password specified" if @password.nil?
    send_data PasswordMessage.new(@password.crypt(msg.salt)).dump

  when AuthentificationMD5Password
    raise ArgumentError, "no password specified" if @password.nil?
    require 'digest/md5'

    m = Digest::MD5.hexdigest(@password + @user)
    m = Digest::MD5.hexdigest(m + msg.salt)
    m = 'md5' + m
    send_data PasswordMessage.new(m).dump

  when AuthentificationKerberosV4, AuthentificationKerberosV5, AuthentificationSCMCredential
    raise "unsupported authentification"

  when AuthentificationOk
  when ErrorResponse
    raise msg.field_values.join("\t")
  when NoticeResponse
    @notice_processor.call(msg) if @notice_processor
  when ParameterStatus
    @params[msg.key] = msg.value
  when BackendKeyData
    # TODO
    #p msg
  when ReadyForQuery
    # TODO: use transaction status
    pc,@pending_conn = @pending_conn,nil
    pc.succeed true
  else
    raise "unhandled message type"
  end
end

#dispatch_query_message(msg) ⇒ Object

Cloned and modified from the postgres-pr.



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# File 'lib/postgres_connection.rb', line 183

def dispatch_query_message(msg)
  case msg
  when DataRow
    @r.rows << msg.columns
  when CommandComplete
    @r.cmd_tag = msg.cmd_tag
  when ReadyForQuery
    pq,@pending_query = @pending_query,nil
    pq.succeed @e.size == 0, @r, @e
  when RowDescription
    @r.fields = msg.fields
  when CopyInResponse
  when CopyOutResponse
  when EmptyQueryResponse
  when ErrorResponse
    @e << msg.field_values[2]
  when NoticeResponse
    @notice_processor.call(msg) if @notice_processor
  when ParameterStatus
  else
    # TODO
    puts "Unknown Postgres message: #{msg}"
  end
end

#exec(sql) ⇒ Object

Fibered impl for synchronous execution of SQL within EM

Raises:

  • (RuntimeError) 


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# File 'lib/postgres_connection.rb', line 40

def exec(sql)
  fiber = Fiber.current
#        p [fiber.object_id, self.object_id, sql]
  yielding = true
  (status, result, errors) = nil
  d = query(sql)
  d.callback do |s, r, e|
    (status, result, errors) = s, r, e
    fiber.resume
  end
  d.errback do |msg|
    errors = msg
    status = false
    # errback is called from the same fiber
    yielding = false
  end
  
  Fiber.yield if yielding
#        p [fiber.object_id, self.object_id, result]
  return PGresult.new(result) if status
  raise RuntimeError, (errors || result).inspect
end

#post_init ⇒ Object 



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# File 'lib/postgres_connection.rb', line 71

def post_init
  @connected = true
end

#query(sql) ⇒ Object 



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# File 'lib/postgres_connection.rb', line 102

def query(sql)
  d = EM::DefaultDeferrable.new
  d.timeout 15

  if !@connected
    d.fail "Not connected"
  elsif @pending_query || @pending_conn
    d.fail "Operation already in progress"
  else
    @r = PostgresPR::Connection::Result.new
    @e = []
    @pending_query = d
    send_data PostgresPR::Query.dump(sql)
  end

  d
end

#receive_data(data) ⇒ Object 



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# File 'lib/postgres_connection.rb', line 120

def receive_data(data)
  @data << data
  while @data.length >= 5
    pktlen = @data[1...5].unpack("N").first
    if @data.length >= (1 + pktlen)
      pkt = @data.slice!(0...(1+pktlen))
      m = StringIO.open( pkt, "r" ) {|io| PostgresPR::Message.read( io ) }
      if @pending_conn
        dispatch_conn_message m
      elsif @pending_query
        dispatch_query_message m
      else
        raise "Unexpected message from database"
      end
    else
      break # very important, break out of the while
    end
  end
end

#unbind ⇒ Object 



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# File 'lib/postgres_connection.rb', line 75

def unbind
  @connected = false
  if o = (@pending_query || @pending_conn)
    o.succeed false, "lost connection"
  end
end