Class: CGI::Session::ActiveRecordStore::SqlBypass

Inherits:
Object
  • Object
show all
Defined in:
lib/action_controller/session/active_record_store.rb

Overview

A barebones session store which duck-types with the default session store but bypasses Active Record and issues SQL directly.

The database connection, table name, and session id and data columns are configurable class attributes. Marshaling and unmarshaling are implemented as class methods that you may override. By default, marshaling data is Base64.encode64(Marshal.dump(data)) and unmarshaling data is Marshal.load(Base64.decode64(data)).

This marshaling 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'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(attributes) ⇒ SqlBypass

Look for normal and marshaled data, self.find_by_session_id's way of telling us to postpone unmarshaling 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/action_controller/session/active_record_store.rb', line 204

def initialize(attributes)
  @session_id, @data, @marshaled_data = attributes[:session_id], attributes[:data], attributes[:marshaled_data]
  @new_record = @marshaled_data.nil?
end

Instance Attribute Details

#dataObject

Lazy-unmarshal session state. Take a fingerprint so we can detect whether to save changes later.


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# File 'lib/action_controller/session/active_record_store.rb', line 215

def data
  unless @data
    if @marshaled_data
      @fingerprint = self.class.fingerprint(@marshaled_data)
      @data, @marshaled_data = self.class.unmarshal(@marshaled_data), nil
    else
      @data = {}
      @fingerprint = nil
    end
  end
  @data
end

#session_idObject (readonly)

Returns the value of attribute session_id


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# File 'lib/action_controller/session/active_record_store.rb', line 198

def session_id
  @session_id
end

Class Method Details

.connectionObject


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# File 'lib/action_controller/session/active_record_store.rb', line 168

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

.create_table!Object


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# File 'lib/action_controller/session/active_record_store.rb', line 183

def create_table!
  @@connection.execute <<-end_sql
    CREATE TABLE #{table_name} (
      id INTEGER PRIMARY KEY,
      #{@@connection.quote_column_name(session_id_column)} TEXT UNIQUE,
      #{@@connection.quote_column_name(data_column)} TEXT
    )
  end_sql
end

.drop_table!Object


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# File 'lib/action_controller/session/active_record_store.rb', line 193

def drop_table!
  @@connection.execute "DROP TABLE #{table_name}"
end

.find_by_session_id(session_id) ⇒ Object

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


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# File 'lib/action_controller/session/active_record_store.rb', line 173

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

.fingerprint(data) ⇒ Object


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# File 'lib/action_controller/session/active_record_store.rb', line 181

def fingerprint(data) Digest::MD5.hexdigest(data)         end

.marshal(data) ⇒ Object


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# File 'lib/action_controller/session/active_record_store.rb', line 179

def marshal(data)     Base64.encode64(Marshal.dump(data)) end

.unmarshal(data) ⇒ Object


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# File 'lib/action_controller/session/active_record_store.rb', line 180

def unmarshal(data)   Marshal.load(Base64.decode64(data)) end

Instance Method Details

#destroyObject


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# File 'lib/action_controller/session/active_record_store.rb', line 253

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

#new_record?Boolean

Returns:

  • (Boolean)

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# File 'lib/action_controller/session/active_record_store.rb', line 209

def new_record?
  @new_record
end

#saveObject


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# File 'lib/action_controller/session/active_record_store.rb', line 228

def save
  marshaled_data = self.class.marshal(data)

  if @new_record
    @new_record = false
    @@connection.update <<-end_sql, 'Create session'
      INSERT INTO #{@@table_name} (
        #{@@connection.quote_column_name(@@session_id_column)},
        #{@@connection.quote_column_name(@@data_column)} )
      VALUES (
        #{@@connection.quote(session_id)},
        #{@@connection.quote(marshaled_data)} )
    end_sql
  else
    old_fingerprint, @fingerprint = @fingerprint, self.class.fingerprint(marshaled_data)
    if old_fingerprint != @fingerprint
      @@connection.update <<-end_sql, 'Update session'
        UPDATE #{@@table_name}
        SET #{@@connection.quote_column_name(@@data_column)}=#{@@connection.quote(marshaled_data)}
        WHERE #{@@connection.quote_column_name(@@session_id_column)}=#{@@connection.quote(session_id)}
      end_sql
    end
  end
end