Class: Memcache::PGServer

Inherits:
Base
  • Object
show all
Defined in:
lib/memcache/pg_server.rb

Instance Attribute Summary collapse

Attributes inherited from Base

#prefix

Instance Method Summary collapse

Methods inherited from Base

#cas, #clear, #gets

Constructor Details

#initialize(opts) ⇒ PGServer

Returns a new instance of PGServer.



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# File 'lib/memcache/pg_server.rb', line 15

def initialize(opts)
  @table = opts[:table]
  @db    = opts[:db] || ActiveRecord::Base.connection.raw_connection
end

Instance Attribute Details

#db ⇒ Object (readonly)

Returns the value of attribute db.



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# File 'lib/memcache/pg_server.rb', line 13

def db
  @db
end

#table ⇒ Object (readonly)

Returns the value of attribute table.



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# File 'lib/memcache/pg_server.rb', line 13

def table
  @table
end

Instance Method Details

#add(key, value, expiry = 0, flags = 0) ⇒ Object 



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# File 'lib/memcache/pg_server.rb', line 87

def add(key, value, expiry = 0, flags = 0)
  delete_expired(key)
  insert(key, value, expiry, flags)
  value
rescue PGError => e
  nil
end

#append(key, value) ⇒ Object 



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# File 'lib/memcache/pg_server.rb', line 101

def append(key, value)
  delete_expired(key)
  result = db.exec %{
    UPDATE #{table}
      SET value = value || #{quote(value)}, updated_at = NOW()
      WHERE key = #{quote(key)} AND #{prefix_clause}
  }
  result.cmdtuples == 1
end

#decr(key, amount = 1) ⇒ Object 



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# File 'lib/memcache/pg_server.rb', line 67

def decr(key, amount = 1)
  incr(key, -amount)
end

#delete(key) ⇒ Object 



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# File 'lib/memcache/pg_server.rb', line 71

def delete(key)
  result = db.exec %{
    DELETE FROM #{table}
      WHERE key = #{quote(key)} AND #{prefix_clause}
  }
  result.cmdtuples == 1
end

#flush_all(delay = nil) ⇒ Object 



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# File 'lib/memcache/pg_server.rb', line 27

def flush_all(delay = nil)
  db.exec("TRUNCATE #{table}")
end

#get(keys, cas = false) ⇒ Object 



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# File 'lib/memcache/pg_server.rb', line 31

def get(keys, cas = false)
  # cas ignored for now
  return get([keys])[keys.to_s] unless keys.kind_of?(Array)
  return {} if keys.empty?

  keys = keys.collect {|key| quote(key.to_s)}.join(',')
  sql = %{
    SELECT key, value, flags FROM #{table}
      WHERE key IN (#{keys}) AND #{prefix_clause} AND #{expiry_clause}
  }

  results = {}
  db.query(sql).each do |row|
    results[row['key']] = {:value => row['value'], :flags => row['flags'].to_i}
  end
  results
end

#incr(key, amount = 1) ⇒ Object 



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# File 'lib/memcache/pg_server.rb', line 49

def incr(key, amount = 1)
  transaction do
    result = get(key)
    return unless result

    value = result[:value]
    return unless value =~ /^\d+$/

    value = value.to_i + amount
    value = 0 if value < 0
    db.exec %{
      UPDATE #{table} SET value = #{quote(value)}, updated_at = NOW()
        WHERE key = #{quote(key)} AND #{prefix_clause}
    }
    value
  end
end

#name ⇒ Object 



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# File 'lib/memcache/pg_server.rb', line 20

def name
  @name ||= begin
    db_config = db.instance_variable_get(:@config)
    "#{db_config[:host]}:#{db_config[:database]}:#{table}"
  end
end

#prepend(key, value) ⇒ Object 



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# File 'lib/memcache/pg_server.rb', line 111

def prepend(key, value)
  delete_expired(key)
  result = db.exec %{
    UPDATE #{table}
      SET value = #{quote(value)} || value, updated_at = NOW()
      WHERE key = #{quote(key)} AND #{prefix_clause}
  }
  result.cmdtuples == 1
end

#replace(key, value, expiry = 0, flags = 0) ⇒ Object 



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# File 'lib/memcache/pg_server.rb', line 95

def replace(key, value, expiry = 0, flags = 0)
  delete_expired(key)
  result = update(key, value, expiry, flags)
  result.cmdtuples == 1 ? value : nil
end

#set(key, value, expiry = 0, flags = 0) ⇒ Object 



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# File 'lib/memcache/pg_server.rb', line 79

def set(key, value, expiry = 0, flags = 0)
  transaction do
    delete(key)
    insert(key, value, expiry, flags)
  end
  value
end