Class: Capistrano::Configuration::ValidatedVariables

Inherits:
SimpleDelegator
  • Object
show all
Includes:
ProcHelpers
Defined in:
lib/capistrano/configuration/validated_variables.rb

Overview

Decorates a Variables object to additionally perform an optional set of user-supplied validation rules. Each rule for a given key is invoked immediately whenever ‘set` is called with a value for that key.

If ‘set` is called with a callable value or a block, validation is not performed immediately. Instead, the validation rules are invoked the first time `fetch` is used to access the value.

A rule is simply a block that accepts two arguments: key and value. It is up to the rule to raise an exception when it deems the value is invalid (or just print a warning).

Rules can be registered using the DSL like this:

validate(:my_key) do |key, value|
  # rule goes here
end

Defined Under Namespace

Classes: ValidatedQuestion

Instance Method Summary collapse

Methods included from ProcHelpers

callable_without_parameters?

Constructor Details

#initialize(variables) ⇒ ValidatedVariables

Returns a new instance of ValidatedVariables.



27
28
29
30
 
# File 'lib/capistrano/configuration/validated_variables.rb', line 27

def initialize(variables)
  super(variables)
  @validators = {}
end

Instance Method Details

#set(key, value = nil, &block) ⇒ Object

Decorate Variables#set to add validation behavior.



33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
 
# File 'lib/capistrano/configuration/validated_variables.rb', line 33

def set(key, value=nil, &block)
  assert_value_or_block_not_both(value, block)

  # Skip validation behavior if no validators are registered for this key
  return super unless validators.key?(key)

  value_to_evaluate = block || value

  if callable_without_parameters?(value_to_evaluate)
    super(key, assert_valid_later(key, value_to_evaluate), &nil)
  else
    assert_valid_now(key, value_to_evaluate)
    super
  end
end

#validate(key, &validator) ⇒ Object

Register a validation rule for the given key.



50
51
52
53
54
 
# File 'lib/capistrano/configuration/validated_variables.rb', line 50

def validate(key, &validator)
  vs = (validators[key] || [])
  vs << validator
  validators[key] = vs
end