Class: FlexiRecord::Connection

Inherits:
Object
  • Object
show all
Includes:
MonitorMixin
Defined in:
lib/flexirecord.rb

Overview

A Connection object represents a distinct connection to the database.

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ Connection

Generates a new Connection object. The passed ‘options’ are a hash, which may contain the following keys:

  • :engine (only :postgresql is supported)

  • :host

  • :port

  • :options

  • :db

  • :user

  • :pass

  • :data_types (used for the PostgreSQL interface to supply a mapping between OID’s and ruby types, will be set automatically in the hash object, if it is nil or missing)

Raises:

  • (ArgumentError) 


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# File 'lib/flexirecord.rb', line 1219

def initialize(options)
  super()
  options.each do |key, value|
    case key
    when :engine
      @engine = value.to_sym
    when :host
      @host = value.to_s.dup.freeze if value
    when :port
      @port = value.to_i
    when :options
      @options = options.to_s.dup.freeze if value
    when :db
      @dbname = value.to_s.dup.freeze if value
    when :user
      @login = value.to_s.dup.freeze if value
    when :pass
      @passwd = value.to_s.dup.freeze if value
    when :data_types
      @data_types = value.to_hash.dup.freeze if value
    else
      raise ArgumentError, "Unknown option '#{key}'."
    end
  end
  raise ArgumentError, "No engine selected." if @engine.nil?
  raise ArgumentError, "Engine '#{@engine}' not supported." unless @engine == :postgresql
  unless @data_types
    @data_types = {}
    options[:data_types] = {}
    connection = nil
    begin
      connection = FlexiRecord::Connection.new(options)
      connection.query('SELECT "oid", "typname" FROM "pg_type" WHERE typtype=$', 'b').each do |type_record|
      @data_types[type_record.oid.to_i] = type_record.typname.to_s.freeze
      end
    ensure
      connection.close if connection
    end
    options[:data_types] = @data_types.freeze
  end
  begin
    @backend_connection = PGconn.new(@host, @port, @options, nil, @dbname, @login, @passwd)
  rescue PGError
    raise FlexiRecord::DatabaseError, $!.message
  end
  @transaction_stacklevel = 0
  @isolation_level = nil
  @spoiled = false
  nil
end

Instance Method Details

#close ⇒ Object

Closes the connection. The connection object must not be used after it is closed.



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# File 'lib/flexirecord.rb', line 1493

def close
  @backend_connection.close
  @backend_connection = nil
  nil
end

#execute(command_template, *command_arguments) ⇒ Object

Same as record_query, but having no ‘record_class’, theirfor returning nil.



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# File 'lib/flexirecord.rb', line 1398

def execute(command_template, *command_arguments)
  record_query(nil, command_template, *command_arguments)
end

#isolation_level ⇒ Object

Returns the isolation_level of a transaction in progress on this connection.



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# File 'lib/flexirecord.rb', line 1410

def isolation_level
  synchronize do
    @isolation_level
  end
end

#query(command_template, *command_arguments) ⇒ Object

Same as record_query, but using BaseRecord’s as ‘record_class’.



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# File 'lib/flexirecord.rb', line 1393

def query(command_template, *command_arguments)
  record_query(FlexiRecord::BaseRecord, command_template, *command_arguments)
end

#record_query(record_class, command_template, *command_arguments) ⇒ Object

Executes an SQL query and returns an Array of objects of ‘record_class’ (which should be a sub-class of BaseRecord). The ‘command_template’ is an SQL statement with ‘$’ placeholders to be replaced by the following ‘command_arguments’.

Raises:

  • (ArgumentError) 


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# File 'lib/flexirecord.rb', line 1276

def record_query(record_class, command_template, *command_arguments)
  command = command_template.to_s.gsub(/\$([^0-9]|$)/) {
    rest = $1
    if command_arguments.empty?
      raise ArgumentError, "Too few arguments supplied for SQL command."
    end
    command_argument = command_arguments.shift
    if command_argument.kind_of? Float
      if command_argument.finite?
        PGconn.quote(command_argument)
      elsif command_argument.nan?
        "'NaN'"
      elsif command_argument < 0
        "'-Infinity'"
      else
        "'Infinity'"
      end
    else
      if command_argument.kind_of? Rational
        command_argument = command_argument.to_f
      elsif command_argument.kind_of? Time
        time_offset_hours = command_argument.utc_offset / 3600
        unless 3600 * time_offset_hours == command_argument.utc_offset
          raise "Time zone offset is not an integer amount of hours."
        end
        command_argument = "%s.%06i%+03i" % [command_argument.strftime("%Y-%m-%d %H:%M:%S"), command_argument.usec, time_offset_hours]
      end
      PGconn.quote(command_argument)
    end << rest
    # argument = command_arguments.shift
    # if argument.kind_of? FlexiRecord::SqlSnippet
    #   argument.to_s + $1
    # else
    #   PGconn.quote(argument) << $1
    # end
  }
  raise ArgumentError, "Too many arguments supplied for SQL command." unless command_arguments.empty?
  if $flexirecord_debug_output
    $flexirecord_debug_output << "#{command}\n"
  end
  begin
    synchronize do
      if record_class
        backend_result = @backend_connection.async_exec(command)
        result = FlexiRecord::RecordArray.new(record_class)
        for row in 0...(backend_result.num_tuples)
          record_data = {}
          for col in 0...(backend_result.num_fields)
            value_string = backend_result.getvalue(row, col)
            record_data[backend_result.fieldname(col)] = if value_string.nil?
              nil
            else
              if @data_types
                data_type = @data_types[backend_result.type(col)]
                if data_type == "bool"
                  value_string[0, 1] == 't'
                elsif ["int2", "int4", "int8"].include? data_type
                  value_string.to_i
                elsif ["text", "varchar"].include? data_type
                  value_string
                elsif data_type == "numeric"
                  unless value_string =~ /^([+-]?[0-9]*)(\.([0-9]+)?)?$/
                    raise "Unexpected format for numeric data from database."
                  end
                  if $3
                    $1.to_i + Rational($3.to_i, 10**($3.length)) * (($1[0, 1] == '-') ? -1 : 1)
                  else
                    $1.to_i
                  end
                elsif ["float4", "float8"].include? data_type
                  if value_string =~ /^NaN$/i
                    0.0 / 0.0
                  elsif value_string =~ /^Infinity$/i
                    1.0 / 0.0
                  elsif value_string =~ /^-Infinity$/i
                    -1.0 / 0.0
                  else
                    value_string.to_f
                  end
                elsif data_type == "date"
                  unless value_string =~ /^([0-9]{4})-([0-9]{2})-([0-9]{2})$/
                    raise "Unexpected format for date from database."
                  end
                  Time.local($1.to_i, $2.to_i, $3.to_i)
                elsif data_type == "timestamp"
                  unless value_string =~ /^([0-9]{4})-([0-9]{2})-([0-9]{2}) ([0-9]{2}):([0-9]{2}):([0-9]{2})(\.([0-9]*))?$/
                    raise "Unexpected format for timestamp without time zone from database."
                  end
                  Time.local($1.to_i, $2.to_i, $3.to_i, $4.to_i, $5.to_i, $6.to_i, $8.to_i * 10 ** (6 - $8.to_s.length))
                elsif data_type == "timestamptz"
                  unless value_string =~ /^([0-9]{4})-([0-9]{2})-([0-9]{2}) ([0-9]{2}):([0-9]{2}):([0-9]{2})(\.([0-9]*))?( ?[+-][0-9]{2})$/
                    aise "Unexpected format for timestamp with time zone from database."
                  end
                  (Time.utc($1.to_i, $2.to_i, $3.to_i, $4.to_i, $5.to_i, $6.to_i, $8.to_i * 10 ** (6 - $8.to_s.length)) - (3600 * $9.to_i)).localtime
                else
                  value_string
                end
              else
                value_string
              end
            end
          end
          result << record_class.new(record_data, true)
        end
        return result
      else
        @backend_connection.async_exec(command)
        return nil
      end
    end
  rescue PGError
    @spoiled = true
    raise FlexiRecord::DatabaseError, $!.message
  end
end

#spoiled? ⇒ Boolean

Returns true, if an error has been occured in the lifetime of this connection.

Returns:

  • (Boolean) 


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# File 'lib/flexirecord.rb', line 1271

def spoiled?
  @spoiled
end

#transaction(*arguments) ⇒ Object

Starts a transaction or “nested transaction” (implemented by using save points), if already one is in progress. The arguments to this function can be an IsolationLevel constant, a symbol representing an IsolationLevel, the special symbol :unless_open or any number of BaseRecord objects, which are copied with BaseRecord#dup and restored with BaseRecord#replace, in case the transaction fails. If :unless_open is specified, and a transaction is already open, this method does nothing, except calling the given block. As partitial rollbacks on errors won’t happen in this case, it’s not recommended to use the :unless_open parameter, unless you know what you are doing. IsolationLevel’s are only regarded, if there is no transaction open yet.



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# File 'lib/flexirecord.rb', line 1417

def transaction(*arguments)
  isolation_level = nil
  records = []
  unless_open_mode = false
  arguments.flatten.each do |argument|
    if argument.kind_of? FlexiRecord::IsolationLevel
      isolation_level_argument = argument
    elsif argument.respond_to? :to_sym
      isolation_level_argument = FlexiRecord::IsolationLevel.by_symbol(argument)
    end
    if argument.nil?
      # nothing
    elsif argument == :unless_open
      unless_open_mode = true
    elsif isolation_level_argument
      unless isolation_level.nil?
        raise ArgumentError, "Multiple isolation levels given."
      end
      isolation_level = isolation_level_argument
    elsif argument.kind_of? Symbol
      raise ArgumentError, "Unknown symbol #{argument.inspect} given as argument to transaction method."
    else
      records << argument
    end
  end
  if unless_open_mode and not records.empty?
    raise ArgumentError, "No records may be specified, if a transaction is started 'unless_open'."
  end
  synchronize do
    if unless_open_mode and transaction?
      return yield
    end
    backup = records.collect { |record| record.dup }
    old_stacklevel = @transaction_stacklevel
    success = true
    begin
      if @transaction_stacklevel == 0
        @isolation_level = isolation_level
        if isolation_level
          execute("BEGIN TRANSACTION ISOLATION LEVEL #{isolation_level}")
        else
          execute('BEGIN TRANSACTION')
        end
      else
        execute('SAVEPOINT "FlexiRecord_' << @transaction_stacklevel.to_s << '"')
      end
      @transaction_stacklevel += 1
      return yield
    rescue StandardError
      success = false
      raise $!
    ensure
      @transaction_stacklevel = old_stacklevel
      if success
        if old_stacklevel == 0
          execute('COMMIT TRANSACTION')
        else
          execute('RELEASE SAVEPOINT "FlexiRecord_' << @transaction_stacklevel.to_s << '"')
        end
      else
        if old_stacklevel == 0
          @isolation_level = 0
          execute('ROLLBACK TRANSACTION')
        else
          execute('ROLLBACK TO SAVEPOINT "FlexiRecord_' << @transaction_stacklevel.to_s << '"')
          execute('RELEASE SAVEPOINT "FlexiRecord_' << @transaction_stacklevel.to_s << '"')
        end
        backup.each_index do |record_index|
          records[record_index].replace(backup[record_index])
        end
      end
    end
  end
end

#transaction? ⇒ Boolean

Returns true, if a transaction is in progress on this connection.

Returns:

  • (Boolean) 


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# File 'lib/flexirecord.rb', line 1403

def transaction?
  synchronize do
    @transaction_stacklevel > 0
  end
end