Class: Liquid::Strainer

Inherits:
Object
  • Object
show all
Defined in:
lib/liquid/strainer.rb

Overview

Strainer is the parent class for the filters system. New filters are mixed into the strainer class which is then instantiated for each liquid template render run.

The Strainer only allows method calls defined in filters given to it via Strainer.global_filter, Context#add_filters or Template.register_filter

Constant Summary collapse

@@filters =

:nodoc:

[]
@@known_filters = 
Set.new
@@known_methods = 
Set.new
@@strainer_class_cache = 
Hash.new do |hash, filters|
  hash[filters] = Class.new(Strainer) do
    filters.each { |f| include f }
  end
end

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(context) ⇒ Strainer

Returns a new instance of Strainer.



20
21
22
 
# File 'lib/liquid/strainer.rb', line 20

def initialize(context)
  @context = context
end

Class Method Details

.add_known_filter(filter) ⇒ Object 



30
31
32
33
34
35
36
37
38
 
# File 'lib/liquid/strainer.rb', line 30

def self.add_known_filter(filter)
  unless @@known_filters.include?(filter)
    @@method_blacklist ||= Set.new(Strainer.instance_methods.map(&:to_s))
    new_methods = filter.instance_methods.map(&:to_s)
    new_methods.reject!{ |m| @@method_blacklist.include?(m) }
    @@known_methods.merge(new_methods)
    @@known_filters.add(filter)
  end
end

.create(context, filters = []) ⇒ Object 



44
45
46
47
 
# File 'lib/liquid/strainer.rb', line 44

def self.create(context, filters = [])
  filters = @@filters + filters
  strainer_class_cache[filters].new(context)
end

.global_filter(filter) ⇒ Object

Raises:



24
25
26
27
28
 
# File 'lib/liquid/strainer.rb', line 24

def self.global_filter(filter)
  raise ArgumentError, "Passed filter is not a module" unless filter.is_a?(Module)
  add_known_filter(filter)
  @@filters << filter unless @@filters.include?(filter)
end

.strainer_class_cache ⇒ Object 



40
41
42
 
# File 'lib/liquid/strainer.rb', line 40

def self.strainer_class_cache
  @@strainer_class_cache
end

Instance Method Details

#invokable?(method) ⇒ Boolean

Returns:

  • (Boolean) 


59
60
61
 
# File 'lib/liquid/strainer.rb', line 59

def invokable?(method)
  @@known_methods.include?(method.to_s) && respond_to?(method)
end

#invoke(method, *args) ⇒ Object 



49
50
51
52
53
54
55
56
57
 
# File 'lib/liquid/strainer.rb', line 49

def invoke(method, *args)
  if invokable?(method)
    send(method, *args)
  else
    args.first
  end
rescue ::ArgumentError => e
  raise Liquid::ArgumentError.new(e.message)
end