Module: ActiveRecord::ConnectionHandling

Included in:
Base
Defined in:
lib/active_record/connection_adapters/mysql2_adapter.rb,
lib/active_record/connection_handling.rb,
lib/active_record/connection_adapters/sqlite3_adapter.rb,
lib/active_record/connection_adapters/postgresql_adapter.rb

Overview

:nodoc:

Defined Under Namespace

Classes: MergeAndResolveDefaultUrlConfig

Constant Summary collapse

RAILS_ENV =
-> { (Rails.env if defined?(Rails.env)) || ENV["RAILS_ENV"].presence || ENV["RACK_ENV"].presence }
DEFAULT_ENV =
-> { RAILS_ENV.call || "default_env" }

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#connection_specification_nameObject

Return the specification name from the current class or its parent.



96
97
98
99
100
101
# File 'lib/active_record/connection_handling.rb', line 96

def connection_specification_name
  if !defined?(@connection_specification_name) || @connection_specification_name.nil?
    return self == Base ? "primary" : superclass.connection_specification_name
  end
  @connection_specification_name
end

Instance Method Details

#clear_cache!Object

:nodoc:



138
139
140
# File 'lib/active_record/connection_handling.rb', line 138

def clear_cache! # :nodoc:
  connection.schema_cache.clear!
end

#connected?Boolean

Returns true if Active Record is connected.

Returns:

  • (Boolean)


122
123
124
# File 'lib/active_record/connection_handling.rb', line 122

def connected?
  connection_handler.connected?(connection_specification_name)
end

#connectionObject

Returns the connection currently associated with the class. This can also be used to “borrow” the connection to do database work unrelated to any of the specific Active Records.



89
90
91
# File 'lib/active_record/connection_handling.rb', line 89

def connection
  retrieve_connection
end

#connection_configObject

Returns the configuration of the associated connection as a hash:

ActiveRecord::Base.connection_config
# => {pool: 5, timeout: 5000, database: "db/development.sqlite3", adapter: "sqlite3"}

Please use only for reading.



109
110
111
# File 'lib/active_record/connection_handling.rb', line 109

def connection_config
  connection_pool.spec.config
end

#connection_poolObject



113
114
115
# File 'lib/active_record/connection_handling.rb', line 113

def connection_pool
  connection_handler.retrieve_connection_pool(connection_specification_name) || raise(ConnectionNotEstablished)
end

#establish_connection(config = nil) ⇒ Object

Establishes the connection to the database. Accepts a hash as input where the :adapter key must be specified with the name of a database adapter (in lower-case) example for regular databases (MySQL, PostgreSQL, etc):

ActiveRecord::Base.establish_connection(
  adapter:  "mysql2",
  host:     "localhost",
  username: "myuser",
  password: "mypass",
  database: "somedatabase"
)

Example for SQLite database:

ActiveRecord::Base.establish_connection(
  adapter:  "sqlite3",
  database: "path/to/dbfile"
)

Also accepts keys as strings (for parsing from YAML for example):

ActiveRecord::Base.establish_connection(
  "adapter"  => "sqlite3",
  "database" => "path/to/dbfile"
)

Or a URL:

ActiveRecord::Base.establish_connection(
  "postgres://myuser:mypass@localhost/somedatabase"
)

In case ActiveRecord::Base.configurations is set (Rails automatically loads the contents of config/database.yml into it), a symbol can also be given as argument, representing a key in the configuration hash:

ActiveRecord::Base.establish_connection(:production)

The exceptions AdapterNotSpecified, AdapterNotFound and ArgumentError may be returned on an error.



49
50
51
52
53
54
55
56
57
58
59
60
61
# File 'lib/active_record/connection_handling.rb', line 49

def establish_connection(config = nil)
  raise "Anonymous class is not allowed." unless name

  config ||= DEFAULT_ENV.call.to_sym
  spec_name = self == Base ? "primary" : name
  self.connection_specification_name = spec_name

  resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new(Base.configurations)
  spec = resolver.resolve(config).symbolize_keys
  spec[:name] = spec_name

  connection_handler.establish_connection(spec)
end

#mysql2_connection(config) ⇒ Object

Establishes a connection to the database that's used by all Active Record objects.



12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
# File 'lib/active_record/connection_adapters/mysql2_adapter.rb', line 12

def mysql2_connection(config)
  config = config.symbolize_keys
  config[:flags] ||= 0

  if config[:flags].kind_of? Array
    config[:flags].push "FOUND_ROWS".freeze
  else
    config[:flags] |= Mysql2::Client::FOUND_ROWS
  end

  client = Mysql2::Client.new(config)
  ConnectionAdapters::Mysql2Adapter.new(client, logger, nil, config)
rescue Mysql2::Error => error
  if error.message.include?("Unknown database")
    raise ActiveRecord::NoDatabaseError
  else
    raise
  end
end

#postgresql_connection(config) ⇒ Object

Establishes a connection to the database that's used by all Active Record objects



33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
# File 'lib/active_record/connection_adapters/postgresql_adapter.rb', line 33

def postgresql_connection(config)
  conn_params = config.symbolize_keys

  conn_params.delete_if { |_, v| v.nil? }

  # Map ActiveRecords param names to PGs.
  conn_params[:user] = conn_params.delete(:username) if conn_params[:username]
  conn_params[:dbname] = conn_params.delete(:database) if conn_params[:database]

  # Forward only valid config params to PG::Connection.connect.
  valid_conn_param_keys = PG::Connection.conndefaults_hash.keys + [:requiressl]
  conn_params.slice!(*valid_conn_param_keys)

  # The postgres drivers don't allow the creation of an unconnected PG::Connection object,
  # so just pass a nil connection object for the time being.
  ConnectionAdapters::PostgreSQLAdapter.new(nil, logger, conn_params, config)
end

#remove_connection(name = nil) ⇒ Object



126
127
128
129
130
131
132
133
134
135
136
# File 'lib/active_record/connection_handling.rb', line 126

def remove_connection(name = nil)
  name ||= @connection_specification_name if defined?(@connection_specification_name)
  # if removing a connection that has a pool, we reset the
  # connection_specification_name so it will use the parent
  # pool.
  if connection_handler.retrieve_connection_pool(name)
    self.connection_specification_name = nil
  end

  connection_handler.remove_connection(name)
end

#retrieve_connectionObject



117
118
119
# File 'lib/active_record/connection_handling.rb', line 117

def retrieve_connection
  connection_handler.retrieve_connection(connection_specification_name)
end

#sqlite3_connection(config) ⇒ Object



17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
# File 'lib/active_record/connection_adapters/sqlite3_adapter.rb', line 17

def sqlite3_connection(config)
  # Require database.
  unless config[:database]
    raise ArgumentError, "No database file specified. Missing argument: database"
  end

  # Allow database path relative to Rails.root, but only if the database
  # path is not the special path that tells sqlite to build a database only
  # in memory.
  if ":memory:" != config[:database]
    config[:database] = File.expand_path(config[:database], Rails.root) if defined?(Rails.root)
    dirname = File.dirname(config[:database])
    Dir.mkdir(dirname) unless File.directory?(dirname)
  end

  db = SQLite3::Database.new(
    config[:database].to_s,
    results_as_hash: true
  )

  db.busy_timeout(ConnectionAdapters::SQLite3Adapter.type_cast_config_to_integer(config[:timeout])) if config[:timeout]

  ConnectionAdapters::SQLite3Adapter.new(db, logger, nil, config)
rescue Errno::ENOENT => error
  if error.message.include?("No such file or directory")
    raise ActiveRecord::NoDatabaseError
  else
    raise
  end
end