Class: ActiveRecord::SessionStore::SqlBypass

Inherits:
Object
  • Object
show all
Extended by:
ClassMethods
Defined in:
lib/active_record/session_store/sql_bypass.rb

Overview

A barebones session store which duck-types with the default session store but bypasses Active Record and issues SQL directly. This is an example session model class meant as a basis for your own classes.

The database connection, table name, and session id and data columns are configurable class attributes. Serializing and deserializeing are implemented as class methods that you may override. By default, serializing data is

::Base64.encode64(Marshal.dump(data))

and deserializing data is

Marshal.load(::Base64.decode64(data))

This serializing behavior is intended to store the widest range of binary session data in a text column. For higher performance, store in a blob column instead and forgo the Base64 encoding.

Constant Summary collapse

@@table_name = 
'sessions'
@@session_id_column = 
'session_id'
@@data_column = 
'data'

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from ClassMethods

create_table!, deserialize, drop_table!, serialize, serializer_class

Constructor Details

#initialize(attributes) ⇒ SqlBypass

Look for normal and serialized data, self.find_by_session_id's way of telling us to postpone deserializing until the data is requested. We need to handle a normal data attribute in case of a new record.



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# File 'lib/active_record/session_store/sql_bypass.rb', line 78

def initialize(attributes)
  @session_id = attributes[:session_id]
  @retrieved_by = attributes[:retrieved_by]
  @data           = attributes[:data]
  @serialized_data = attributes[:serialized_data]
  @new_record     = @serialized_data.nil?
  @data_changed    = false
end

Class Attribute Details

.connection ⇒ Object 



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# File 'lib/active_record/session_store/sql_bypass.rb', line 53

def connection
  @connection ||= ActiveRecord::Base.connection
end

.connection_pool ⇒ Object 



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# File 'lib/active_record/session_store/sql_bypass.rb', line 57

def connection_pool
  @connection_pool ||= ActiveRecord::Base.connection_pool
end

Instance Attribute Details

#new_record ⇒ Object (readonly) Also known as: new_record?

Returns the value of attribute new_record.



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# File 'lib/active_record/session_store/sql_bypass.rb', line 71

def new_record
  @new_record
end

#session_id ⇒ Object

Returns the value of attribute session_id.



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# File 'lib/active_record/session_store/sql_bypass.rb', line 72

def session_id
  @session_id
end

Class Method Details

.find_by_session_id(session_id) ⇒ Object

Look up a session by id and deserialize its data if found.



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# File 'lib/active_record/session_store/sql_bypass.rb', line 62

def find_by_session_id(session_id)
  if record = connection.select_one("SELECT #{connection.quote_column_name(data_column)} AS data FROM #{@@table_name} WHERE #{connection.quote_column_name(@@session_id_column)}=#{connection.quote(session_id)}")
    new(:session_id => session_id, :retrieved_by => session_id, :serialized_data => record['data'])
  end
end

Instance Method Details

#changed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/session_store/sql_bypass.rb', line 113

def changed?
  persisted? && (@retrieved_by != session_id || @data_changed)
end

#data ⇒ Object

Lazy-deserialize session state.



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# File 'lib/active_record/session_store/sql_bypass.rb', line 93

def data
  unless @data
    if @serialized_data
      @data, @serialized_data = self.class.deserialize(@serialized_data) || {}, nil
    else
      @data = {}
    end
  end
  @data
end

#data=(data) ⇒ Object 



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# File 'lib/active_record/session_store/sql_bypass.rb', line 108

def data=(data)
  @data_changed = true if data != self.data
  @data = data
end

#data_column ⇒ Object

:singleton-method: The data field defaults to 'data'.



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# File 'lib/active_record/session_store/sql_bypass.rb', line 41

cattr_accessor :data_column

#destroy ⇒ Object 



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# File 'lib/active_record/session_store/sql_bypass.rb', line 147

def destroy
  return if @new_record

  connect = connection
  connect.delete <<-end_sql, 'Destroy session'
    DELETE FROM #{table_name}
    WHERE #{connect.quote_column_name(session_id_column)}=#{connect.quote(session_id)}
  end_sql
end

#loaded? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/session_store/sql_bypass.rb', line 104

def loaded?
  @data
end

#persisted? ⇒ Boolean

Returns true if the record is persisted, i.e. it's not a new record

Returns:

  • (Boolean) 


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# File 'lib/active_record/session_store/sql_bypass.rb', line 88

def persisted?
  !@new_record
end

#save ⇒ Object 



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# File 'lib/active_record/session_store/sql_bypass.rb', line 117

def save
  return false unless loaded?
  serialized_data = self.class.serialize(data)
  connect        = connection

  if @new_record
    @new_record = false
    result = connect.update <<-end_sql, 'Create session'
      INSERT INTO #{table_name} (
        #{connect.quote_column_name(session_id_column)},
        #{connect.quote_column_name(data_column)} )
      VALUES (
        #{connect.quote(session_id)},
        #{connect.quote(serialized_data)} )
    end_sql
  else
    result = connect.update <<-end_sql, 'Update session'
      UPDATE #{table_name}
      SET
        #{connect.quote_column_name(data_column)}=#{connect.quote(serialized_data)},
        #{connect.quote_column_name(session_id_column)}=#{connect.quote(@session_id)}
      WHERE #{connect.quote_column_name(session_id_column)}=#{connect.quote(@retrieved_by)}
    end_sql
  end

  @retrieved_by = @session_id
  @data_changed = false
  result
end

#session_id_column ⇒ Object

:singleton-method: The session id field defaults to 'session_id'.



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# File 'lib/active_record/session_store/sql_bypass.rb', line 35

cattr_accessor :session_id_column

#table_name ⇒ Object

:singleton-method: The table name defaults to 'sessions'.



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# File 'lib/active_record/session_store/sql_bypass.rb', line 29

cattr_accessor :table_name