Module: ActiveSupport::Rescuable

Defined in:
lib/active_support/rescuable.rb

Overview

Rescuable module adds support for easier exception handling.

Defined Under Namespace

Modules: ClassMethods

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object

:nodoc:



4
5
6
7
8
9
 
# File 'lib/active_support/rescuable.rb', line 4

def self.included(base) # :nodoc:
  base.class_inheritable_accessor :rescue_handlers
  base.rescue_handlers = []

  base.extend(ClassMethods)
end

Instance Method Details

#handler_for_rescue(exception) ⇒ Object 



78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
 
# File 'lib/active_support/rescuable.rb', line 78

def handler_for_rescue(exception)
  # We go from right to left because pairs are pushed onto rescue_handlers
  # as rescue_from declarations are found.
  _, rescuer = Array(rescue_handlers).reverse.detect do |klass_name, handler|
    # The purpose of allowing strings in rescue_from is to support the
    # declaration of handler associations for exception classes whose
    # definition is yet unknown.
    #
    # Since this loop needs the constants it would be inconsistent to
    # assume they should exist at this point. An early raised exception
    # could trigger some other handler and the array could include
    # precisely a string whose corresponding constant has not yet been
    # seen. This is why we are tolerant to unknown constants.
    #
    # Note that this tolerance only matters if the exception was given as
    # a string, otherwise a NameError will be raised by the interpreter
    # itself when rescue_from CONSTANT is executed.
    klass = self.class.const_get(klass_name) rescue nil
    klass ||= klass_name.constantize rescue nil
    exception.is_a?(klass) if klass
  end

  case rescuer
  when Symbol
    method(rescuer)
  when Proc
    rescuer.bind(self)
  end
end

#rescue_with_handler(exception) ⇒ Object

Tries to rescue the exception by looking up and calling a registered handler.



71
72
73
74
75
76
 
# File 'lib/active_support/rescuable.rb', line 71

def rescue_with_handler(exception)
  if handler = handler_for_rescue(exception)
    handler.arity != 0 ? handler.call(exception) : handler.call
    true # don't rely on the return value of the handler
  end
end