1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
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
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
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
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
|
require 'active_support/core_ext/regexp'
module ActiveRecord
module DynamicMatchers #:nodoc:
def respond_to?(name, include_private = false)
if self == Base
super
else
match = Method.match(self, name)
match && match.valid? || super
end
end
private
def method_missing(name, *arguments, &block)
match = Method.match(self, name)
if match && match.valid?
match.define
send(name, *arguments, &block)
else
super
end
end
class Method
@matchers = []
class << self
attr_reader :matchers
def match(model, name)
klass = matchers.find { |k| k.pattern.match?(name) }
klass.new(model, name) if klass
end
def pattern
@pattern ||= /\A#{prefix}_([_a-zA-Z]\w*)#{suffix}\Z/
end
def prefix
raise NotImplementedError
end
def suffix
''
end
end
attr_reader :model, :name, :attribute_names
def initialize(model, name)
@model = model
@name = name.to_s
@attribute_names = @name.match(self.class.pattern)[1].split('_and_')
@attribute_names.map! { |n| @model.attribute_aliases[n] || n }
end
def valid?
attribute_names.all? { |name| model.columns_hash[name] || model.reflect_on_aggregation(name.to_sym) }
end
def define
model.class_eval <<-CODE, __FILE__, __LINE__ + 1
def self.#{name}(#{signature})
#{body}
end
CODE
end
private
def body
"#{finder}(#{attributes_hash})"
end
# The parameters in the signature may have reserved Ruby words, in order
# to prevent errors, we start each param name with `_`.
def signature
attribute_names.map { |name| "_#{name}" }.join(', ')
end
# Given that the parameters starts with `_`, the finder needs to use the
# same parameter name.
def attributes_hash
"{" + attribute_names.map { |name| ":#{name} => _#{name}" }.join(',') + "}"
end
def finder
raise NotImplementedError
end
end
class FindBy < Method
Method.matchers << self
def self.prefix
"find_by"
end
def finder
"find_by"
end
end
class FindByBang < Method
Method.matchers << self
def self.prefix
"find_by"
end
def self.suffix
"!"
end
def finder
"find_by!"
end
end
end
end
|
