Class: MonetDBConnection

Inherits:
Object
  • Object
show all
Defined in:
lib/MonetDBConnection.rb

Constant Summary collapse

@@DEBUG =

enable debug output

false
@@HOUR =

hour in seconds, used for timezone calculation

3600
@@MAX_MESSAGE_SIZE =

maximum size (in bytes) for a monetdb message to be sent

32766
@@CLIENT_ENDIANNESS =

endianness of a message sent to the server

"BIG"
@@SUPPORTED_PROTOCOLS =

MAPI protocols supported by the driver

[ 8, 9 ]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(user = "monetdb", passwd = "monetdb", lang = "sql", host = "127.0.0.1", port = "50000") ⇒ MonetDBConnection

Instantiates a new MonetDBConnection object

  • user: username (default is monetdb)

  • passwd: password (default is monetdb)

  • lang: language (default is sql)

  • host: server hostanme or ip (default is localhost)

  • port: server port (default is 50000)



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

def initialize(user = "monetdb", passwd = "monetdb", lang = "sql", host="127.0.0.1", port = "50000")
  @user = user
  @passwd = passwd
  @lang = lang.downcase
  @host = host
  @port = port

  @client_endianness = @@CLIENT_ENDIANNESS
  
  @auth_iteration = 0
  @connection_established = false
      
  @transactions = MonetDBTransaction.new # handles a pool of transactions (generates and keeps track of savepoints)
  
  if @@DEBUG == true
    require 'logger'
  end
  
end

Instance Attribute Details

#auto_commit ⇒ Object (readonly)

Returns the value of attribute auto_commit.



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# File 'lib/MonetDBConnection.rb', line 73

def auto_commit
  @auto_commit
end

#lang ⇒ Object (readonly)

Returns the value of attribute lang.



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# File 'lib/MonetDBConnection.rb', line 73

def lang
  @lang
end

#socket ⇒ Object (readonly)

Returns the value of attribute socket.



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# File 'lib/MonetDBConnection.rb', line 73

def socket
  @socket
end

#transactions ⇒ Object (readonly)

Returns the value of attribute transactions.



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# File 'lib/MonetDBConnection.rb', line 73

def transactions
  @transactions
end

Instance Method Details

#auto_commit? ⇒ Boolean

Check the auto commit status (on/off)

Returns:

  • (Boolean) 


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# File 'lib/MonetDBConnection.rb', line 483

def auto_commit?
  @auto_commit
end

#build_auth_string_v8(auth_type, salt, db_name) ⇒ Object

Builds and authentication string given the parameters submitted by the user (MAPI protocol v8).



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# File 'lib/MonetDBConnection.rb', line 314

def build_auth_string_v8(auth_type, salt, db_name)
  # seed = password + salt
  if (auth_type.upcase == "MD5" or auth_type.upcase == "SHA1") and @supported_auth_types.include?(auth_type.upcase)
    auth_type = auth_type.upcase
    digest = Hasher.new(auth_type, @passwd+salt)
    hashsum = digest.hashsum
  elsif auth_type.downcase == "plain" or not  @supported_auth_types.include?(auth_type.upcase)
    auth_type = 'plain'
    hashsum = @passwd + salt
    
  elsif auth_type.downcase == "crypt"
    auth_type =  @supported_auth_types[@supported_auth_types.index(auth_type)+1]
    $stderr.print "The selected hashing algorithm is not supported by the Ruby driver. #{auth_type} will be used instead."
    digest = Hasher.new(auth_type, @passwd+salt)
    hashsum = digest.hashsum
  else
    # The user selected an auth type not supported by the server.
    raise MonetDBConnectionError, "#{auth_type} not supported by the server. Please choose one from #{@supported_auth_types}"
    
  end    
  # Build the reply message with header
  reply = @client_endianness + ":" + @user + ":{" + auth_type + "}" + hashsum + ":" + @lang + ":" + db_name + ":"
end

#build_auth_string_v9(auth_type, salt, db_name) ⇒ Object

Builds and authentication string given the parameters submitted by the user (MAPI protocol v9).



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# File 'lib/MonetDBConnection.rb', line 341

def build_auth_string_v9(auth_type, salt, db_name)
  if (auth_type.upcase == "MD5" or auth_type.upcase == "SHA1") and @supported_auth_types.include?(auth_type.upcase)
    auth_type = auth_type.upcase
    # Hash the password
    pwhash = Hasher.new(@pwhash, @passwd)
    
    digest = Hasher.new(auth_type, pwhash.hashsum + salt)
    hashsum = digest.hashsum
      
  elsif auth_type.downcase == "plain" # or not  @supported_auth_types.include?(auth_type.upcase)
    # Keep it for compatibility with merovingian
    auth_type = 'plain'
    hashsum = @passwd + salt
  elsif @supported_auth_types.include?(auth_type.upcase)
    if auth_type.upcase == "RIPEMD160"
      auth_type =  @supported_auth_types[@supported_auth_types.index(auth_type)+1]
      $stderr.print "The selected hashing algorithm is not supported by the Ruby driver. #{auth_type} will be used instead."
    end
    # Hash the password
    pwhash = Hasher.new(@pwhash, @passwd)
      
    digest = Hasher.new(auth_type, pwhash.hashsum + salt)
    hashsum = digest.hashsum  
  else
    # The user selected an auth type not supported by the server.
    raise MonetDBConnectionError, "#{auth_type} not supported by the server. Please choose one from #{@supported_auth_types}"
  end    
  # Build the reply message with header
  reply = @client_endianness + ":" + @user + ":{" + auth_type + "}" + hashsum + ":" + @lang + ":" + db_name + ":"
end

#connect(db_name = 'demo', auth_type = 'SHA1') ⇒ Object

Connect to the database, creates a new socket



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# File 'lib/MonetDBConnection.rb', line 103

def connect(db_name = 'demo', auth_type = 'SHA1')
  @database = db_name
  @auth_type = auth_type
  
  @socket = TCPSocket.new(@host, @port.to_i)  
  if real_connect
    if @lang == LANG_SQL
      set_timezone 
      set_reply_size
    elsif (@lang == LANG_XQUERY) and XQUERY_OUTPUT_SEQ
      # require xquery output to be in seq format
      send(format_command("output seq"))
    end
    true
  end
  false
end

#disconnect ⇒ Object

Disconnect from server



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# File 'lib/MonetDBConnection.rb', line 273

def disconnect()
  if  @connection_established 
    begin
      @socket.close
    rescue => e
      $stderr.print e
    end
  else
    raise MonetDBConnectionError, "No connection established."
  end
end

#encode_message(msg = "") ⇒ Object

builds a message to be sent to the server



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# File 'lib/MonetDBConnection.rb', line 373

def encode_message(msg = "")    
  message = Array.new
  data = ""
      
  hdr = 0 # package header
  pos = 0
  is_final = false # last package in the stream
  
  while (! is_final)
    data = msg[pos..pos+[@@MAX_MESSAGE_SIZE.to_i, (msg.length - pos).to_i].min]
    pos += data.length 
    
    if (msg.length - pos) == 0
      last_bit = 1
      is_final = true
    else
      last_bit = 0
    end
    
    hdr = [(data.length << 1) | last_bit].pack('v')
    
    message << hdr + data.to_s # Short Little Endian Encoding  
  end
  
  message.freeze # freeze and return the encode message
end

#format_command(x) ⇒ Object

Formats a command string so that it can be parsed by the server



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# File 'lib/MonetDBConnection.rb', line 244

def format_command(x)
    return "X" + x + "\n"
end

#mapi_proto_v8? ⇒ Boolean

Check which protocol is spoken by the server

Returns:

  • (Boolean) 


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# File 'lib/MonetDBConnection.rb', line 505

def mapi_proto_v8?
  if @protocol == 8
    true
  else
    false
  end
end

#mapi_proto_v9? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/MonetDBConnection.rb', line 513

def mapi_proto_v9?
  if @protocol == 9
    true
  else
    false
  end    
end

#merovingian? ⇒ Boolean

Check if monetdb is running behind the merovingian proxy and forward the connection in case

Returns:

  • (Boolean) 


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# File 'lib/MonetDBConnection.rb', line 488

def merovingian?
  if @server_name.downcase == 'merovingian'
    true
  else
    false
  end
end

#mserver? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/MonetDBConnection.rb', line 496

def mserver?
  if @server_name.downcase == 'monetdb'
    true
  else
    false
  end
end

#real_connect ⇒ Object

perform a real connection; retrieve challenge, proxy through merovinginan, build challenge and set the timezone



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# File 'lib/MonetDBConnection.rb', line 123

def real_connect
  
  server_challenge = retrieve_server_challenge()
  print "CHALLENGE: " + server_challenge.to_s
  if server_challenge != nil
    salt = server_challenge.split(':')[0]
    @server_name = server_challenge.split(':')[1]
    @protocol = server_challenge.split(':')[2].to_i
    @supported_auth_types = server_challenge.split(':')[3].split(',')
    @server_endianness = server_challenge.split(':')[4]
    if @protocol == 9
      @pwhash = server_challenge.split(':')[5]
    end
  else
    raise MonetDBConnectionError, "Error: server returned an empty challenge string."
  end
  
  # The server supports only RIPMED168 or crypt as an authentication hash function, but the driver does not.
  if @supported_auth_types.length == 1
    auth = @supported_auth_types[0]
    if auth.upcase == "RIPEMD160" or auth.upcase == "CRYPT"
      raise MonetDBConnectionError, auth.upcase + " " + ": algorithm not supported by ruby-monetdb."
    end
  end
  
  
  # If the server protocol version is not 8: abort and notify the user.
  if @@SUPPORTED_PROTOCOLS.include?(@protocol) == false
    raise MonetDBProtocolError, "Protocol not supported. The current implementation of ruby-monetdb works with MAPI protocols #{@@SUPPORTED_PROTOCOLS} only."
  
  elsif mapi_proto_v8?
    reply = build_auth_string_v8(@auth_type, salt, @database)
  elsif mapi_proto_v9?
    reply = build_auth_string_v9(@auth_type, salt, @database)
  end
           
  if @socket != nil
    @connection_established = true

    send(reply)
    monetdb_auth = receive
    
    if monetdb_auth.length == 0
      # auth succedeed
      true
    else
      if monetdb_auth[0].chr == MSG_REDIRECT
      #redirection
        
        redirects = [] # store a list of possible redirects
        
        monetdb_auth.split('\n').each do |m|
          # strip the trailing ^mapi:
          # if the redirect string start with something != "^mapi:" or is empty, the redirect is invalid and shall not be included.
          if m[0..5] == "^mapi:"
            redir = m[6..m.length]
            # url parse redir
            redirects.push(redir)  
          else
            $stderr.print "Warning: Invalid Redirect #{m}"
          end          
        end
        
        if redirects.size == 0  
          raise MonetDBConnectionError, "No valid redirect received"
        else
          begin 
            uri = URI.split(redirects[0])
            # Splits the string on following parts and returns array with result:
            #
            #  * Scheme
            #  * Userinfo
            #  * Host
            #  * Port
            #  * Registry
            #  * Path
            #  * Opaque
            #  * Query
            #  * Fragment
            server_name = uri[0]
            host   = uri[2]
            port   = uri[3]
            database   = uri[5].gsub(/^\//, '') if uri[5] != nil
          rescue URI::InvalidURIError
            raise MonetDBConnectionError, "Invalid redirect: #{redirects[0]}"
          end
        end
        
        if server_name == "merovingian"
          if @auth_iteration <= 10
            @auth_iteration += 1
            real_connect
          else
            raise MonetDBConnectionError, "Merovingian: too many iterations while proxying."
          end
        elsif server_name == "monetdb"
          begin
            @socket.close
          rescue
            raise MonetDBConnectionError, "I/O error while closing connection to #{@socket}"
          end
          # reinitialize a connection
          @host = host
         @port = port
          
          connect(database, @auth_type)
        else
          @connection_established = false
          raise MonetDBConnectionError, monetdb_auth
        end
      elsif monetdb_auth[0].chr == MSG_INFO
        raise MonetDBConnectionError, monetdb_auth
      end
    end
  end
end

#receive ⇒ Object

receive data from a monetdb5 server instance



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# File 'lib/MonetDBConnection.rb', line 293

def receive
  is_final, chunk_size = recv_decode_hdr

  if chunk_size == 0
   return ""  # needed on ruby-1.8.6 linux/64bit; recv(0) hangs on this configuration. 
  end
  
  data = @socket.recv(chunk_size)
  
  if is_final == false 
    while is_final == false
      is_final, chunk_size = recv_decode_hdr
      data +=  @socket.recv(chunk_size)
    end
  end

  return data
end

#recv_decode_hdr ⇒ Object

reads and decodes the header of a server message



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# File 'lib/MonetDBConnection.rb', line 406

def recv_decode_hdr()
  if @socket != nil
    fb = @socket.recv(1)
    sb = @socket.recv(1)
    
    # Use execeptions handling to keep compatibility between different ruby
    # versions.
    #
    # Chars are treated differently in ruby 1.8 and 1.9
    # try do to ascii to int conversion using ord (ruby 1.9)
    # and if it fail fallback to character.to_i (ruby 1.8)
    begin
      fb = fb[0].ord
      sb = sb[0].ord
    rescue NoMethodError => one_eight
      fb = fb[0].to_i
      sb = sb[0].to_i
    end
    
    chunk_size = (sb << 7) | (fb >> 1)
    
    is_final = false
    if ( (fb & 1) == 1 )
      is_final = true
      
    end
    # return the size of the chunk (in bytes)
    return is_final, chunk_size  
  else  
      raise MonetDBSocketError, "Error while receiving data\n"
  end 
end

#retrieve_server_challenge ⇒ Object

Used as the first step in the authentication phase; retrives a challenge string from the server.



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# File 'lib/MonetDBConnection.rb', line 401

def retrieve_server_challenge()
  server_challenge = receive
end

#savepoint ⇒ Object 



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# File 'lib/MonetDBConnection.rb', line 239

def savepoint
  @transactions.savepoint
end

#send(data) ⇒ Object

send data to a monetdb5 server instance and returns server’s response



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# File 'lib/MonetDBConnection.rb', line 286

def send(data)
  encode_message(data).each do |m|
    @socket.write(m)
  end
end

#set_auto_commit(flag = true) ⇒ Object

Turns auto commit on/off



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# File 'lib/MonetDBConnection.rb', line 463

def set_auto_commit(flag=true)
  if flag == false 
    ac = " 0"
  else 
    ac = " 1"
  end

  send(format_command("auto_commit " + ac))
  
  response = receive
  if response == MSG_PROMPT
    @auto_commit = flag
  elsif response[0].chr == MSG_INFO
    raise MonetDBCommandError, response
    return 
  end
  
end

#set_export(id, idx, offset) ⇒ Object

send an ‘export’ command to the server



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# File 'lib/MonetDBConnection.rb', line 250

def set_export(id, idx, offset)
  send(format_command("export " + id.to_s + " " + idx.to_s + " " + offset.to_s ))
end

#set_output_seq ⇒ Object 



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# File 'lib/MonetDBConnection.rb', line 268

def set_output_seq
  send(format_command("output seq"))
end

#set_reply_size ⇒ Object

send a ‘reply_size’ command to the server



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# File 'lib/MonetDBConnection.rb', line 255

def set_reply_size
  send(format_command(("reply_size " + REPLY_SIZE)))
  
  response = receive

  if response == MSG_PROMPT
    true
  elsif response[0] == MSG_INFO
    raise MonetDBCommandError, "Unable to set reply_size: #{response}"
  end
  
end

#set_timezone ⇒ Object

Sets the time zone according to the Operating System settings



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# File 'lib/MonetDBConnection.rb', line 440

def set_timezone()
  tz = Time.new
  tz_offset = tz.gmt_offset / @@HOUR
    
  if tz_offset <= 9 # verify minute count!
    tz_offset = "'+0" + tz_offset.to_s + ":00'"
  else
    tz_offset = "'+" + tz_offset.to_s + ":00'"
  end
  query_tz = "sSET TIME ZONE INTERVAL " + tz_offset + " HOUR TO MINUTE;"
  
  # Perform the query directly within the method
  send(query_tz)
  response = receive
  
  if response == MSG_PROMPT
    true
  elsif response[0].chr == MSG_INFO
    raise MonetDBQueryError, response
  end
end