Class: SqliteObjectStore

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/sqlite_object_store.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(database_path, table_name = "default_table") ⇒ SqliteObjectStore

Returns a new instance of SqliteObjectStore.



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# File 'lib/sqlite_object_store.rb', line 10

def initialize(database_path, table_name = "default_table")
  @database_path = database_path
  @db = open_database(database_path)
  @table_name = table_name
  create_table(table_name)
  @find_statement = db.prepare "select value from #{table_name} where key = ?"
end

Instance Attribute Details

#database_path ⇒ Object

Returns the value of attribute database_path.



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# File 'lib/sqlite_object_store.rb', line 9

def database_path
  @database_path
end

#db ⇒ Object

Returns the value of attribute db.



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# File 'lib/sqlite_object_store.rb', line 9

def db
  @db
end

#table_name ⇒ Object

Returns the value of attribute table_name.



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# File 'lib/sqlite_object_store.rb', line 9

def table_name
  @table_name
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/sqlite_object_store.rb', line 24

def [](key)
  @find_statement.execute!(String(key)) do |row|
    return json_decode(row.first)
  end
  return nil
end

#[]=(key, value) ⇒ Object 



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# File 'lib/sqlite_object_store.rb', line 31

def []=(key, value)
  db.execute "insert or replace into #{table_name} (key, value) values (?, ?)", String(key), json_encode(value)
end

#close ⇒ Object 



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# File 'lib/sqlite_object_store.rb', line 59

def close
  @find_statement.close
  db.close
  @@databases.delete(File.expand_path(database_path))
end

#create_table(table_name) ⇒ Object 



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# File 'lib/sqlite_object_store.rb', line 55

def create_table(table_name)
  db.execute "create table if not exists #{table_name} (key string primary key, value blob)"
end

#each ⇒ Object 



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# File 'lib/sqlite_object_store.rb', line 35

def each
  db.execute "select key, value from #{table_name}" do |row|
    yield [row[0], json_decode(row[1])]
  end
end

#json_decode(str) ⇒ Object 



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# File 'lib/sqlite_object_store.rb', line 69

def json_decode(str)
  Oj.load(str, :mode => :compat)
end

#json_encode(value) ⇒ Object 



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# File 'lib/sqlite_object_store.rb', line 65

def json_encode(value)
  Oj.dump(value, :mode => :compat)
end

#keys ⇒ Object 



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# File 'lib/sqlite_object_store.rb', line 41

def keys
  key_list = []
  db.execute "select key from #{table_name}" do |row|
    key_list << row[0]
  end
  key_list
end

#open_database(path) ⇒ Object 



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# File 'lib/sqlite_object_store.rb', line 18

def open_database(path)
  full_path = File.expand_path(path)
  @@databases ||= {}
  @@databases[full_path] ||= SQLite3::Database.new(full_path)
end

#size ⇒ Object 



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# File 'lib/sqlite_object_store.rb', line 49

def size
  db.execute "select count(*) from #{table_name}" do |row|
    return row.first
  end
end