Class: CounterCulture::Counter

Inherits:
Object
  • Object
show all
Defined in:
lib/counter_culture/counter.rb

Constant Summary collapse

CONFIG_OPTIONS = 
[ :column_names, :counter_cache_name, :delta_column, :foreign_key_values, :touch, :delta_magnitude, :execute_after_commit ]
ACTIVE_RECORD_VERSION = 
Gem.loaded_specs["activerecord"].version

Instance Method Summary collapse

Constructor Details

#initialize(model, relation, options) ⇒ Counter

Returns a new instance of Counter.



8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
 
# File 'lib/counter_culture/counter.rb', line 8

def initialize(model, relation, options)
  @model = model
  @relation = relation.is_a?(Enumerable) ? relation : [relation]

  @counter_cache_name = options.fetch(:column_name, "#{model.name.demodulize.tableize}_count")
  @column_names = options[:column_names]
  @delta_column = options[:delta_column]
  @foreign_key_values = options[:foreign_key_values]
  @touch = options.fetch(:touch, false)
  @delta_magnitude = options[:delta_magnitude] || 1
  @with_papertrail = options.fetch(:with_papertrail, false)
  @execute_after_commit = options.fetch(:execute_after_commit, false)

  if @execute_after_commit
    begin
      require 'after_commit_action'
    rescue LoadError
      fail(LoadError.new(
        "You need to include the `after_commit_action` gem in your "\
        "gem dependencies to use the execute_after_commit option"))
    end
    model.include(AfterCommitAction)
  end
end

Instance Method Details

#attribute_changed?(obj, attr) ⇒ Boolean

Returns:

  • (Boolean) 


248
249
250
251
252
253
254
 
# File 'lib/counter_culture/counter.rb', line 248

def attribute_changed?(obj, attr)
  if ACTIVE_RECORD_VERSION >= Gem::Version.new("5.1.0")
    obj.saved_changes[attr].present?
  else
    obj.send(:attribute_changed?, attr)
  end
end

#change_counter_cache(obj, options) ⇒ Object

increments or decrements a counter cache

options:

:increment => true to increment, false to decrement
:relation => which relation to increment the count on,
:counter_cache_name => the column name of the counter cache
:counter_column => overrides :counter_cache_name
:delta_column => override the default count delta (1) with the value of this column in the counted record
:was => whether to get the current value or the old value of the
   first part of the relation
:with_papertrail => update the column via Papertrail touch_with_version method



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
124
125
 
# File 'lib/counter_culture/counter.rb', line 44

def change_counter_cache(obj, options)
  change_counter_column = options.fetch(:counter_column) { counter_cache_name_for(obj) }

  # default to the current foreign key value
  id_to_change = foreign_key_value(obj, relation, options[:was])
  # allow overwriting of foreign key value by the caller
  id_to_change = foreign_key_values.call(id_to_change) if foreign_key_values

  if id_to_change && change_counter_column
    delta_magnitude = if delta_column
                        (options[:was] ? attribute_was(obj, delta_column) : obj.public_send(delta_column)) || 0
                      else
                        counter_delta_magnitude_for(obj)
                      end
    # increment or decrement?
    operator = options[:increment] ? '+' : '-'

    klass = relation_klass(relation, source: obj, was: options[:was])

    # MySQL throws an ambiguous column error if any joins are present and we don't include the
    # table name. We isolate this change to MySQL because sqlite has the opposite behavior and
    # throws an exception if the table name is present after UPDATE.
    quoted_column = if klass.connection.adapter_name == 'Mysql2'
                      "#{klass.quoted_table_name}.#{model.connection.quote_column_name(change_counter_column)}"
                    else
                      "#{model.connection.quote_column_name(change_counter_column)}"
                    end

    column_type = klass.type_for_attribute(change_counter_column).type

    # we don't use Rails' update_counters because we support changing the timestamp
    updates = []
    # this updates the actual counter
    if column_type == :money
      updates << "#{quoted_column} = COALESCE(CAST(#{quoted_column} as NUMERIC), 0) #{operator} #{delta_magnitude}"
    else
      updates << "#{quoted_column} = COALESCE(#{quoted_column}, 0) #{operator} #{delta_magnitude}"
    end
    # and here we update the timestamp, if so desired
    if touch
      current_time = klass.send(:current_time_from_proper_timezone)
      timestamp_columns = klass.send(:timestamp_attributes_for_update_in_model)
      if touch != true
        # starting in Rails 6 this is frozen
        timestamp_columns = timestamp_columns.dup
        timestamp_columns << touch
      end
      timestamp_columns.each do |timestamp_column|
        updates << "#{timestamp_column} = '#{current_time.to_formatted_s(:db)}'"
      end
    end

    primary_key = relation_primary_key(relation, source: obj, was: options[:was])

    if @with_papertrail
      instance = klass.where(primary_key => id_to_change).first
      if instance
        if instance.paper_trail.respond_to?(:save_with_version)
          # touch_with_version is deprecated starting in PaperTrail 9.0.0

          current_time = obj.send(:current_time_from_proper_timezone)
          timestamp_columns = obj.send(:timestamp_attributes_for_update_in_model)
          timestamp_columns.each do |timestamp_column|
            instance.send("#{timestamp_column}=", current_time)
          end

          execute_now_or_after_commit(obj) do
            instance.paper_trail.save_with_version(validate: false)
          end
        else
          execute_now_or_after_commit(obj) do
            instance.paper_trail.touch_with_version
          end
        end
      end
    end

    execute_now_or_after_commit(obj) do
      klass.where(primary_key => id_to_change).update_all updates.join(', ')
    end
  end
end

#counter_cache_name_for(obj) ⇒ Object

Gets the name of the counter cache for a specific object

obj: object to calculate the counter cache name for cache_name_finder: object used to calculate the cache name



142
143
144
145
146
147
148
149
150
151
 
# File 'lib/counter_culture/counter.rb', line 142

def counter_cache_name_for(obj)
  # figure out what the column name is
  if counter_cache_name.is_a?(Proc)
    # dynamic column name -- call the Proc
    counter_cache_name.call(obj)
  else
    # static column name
    counter_cache_name
  end
end

#counter_delta_magnitude_for(obj) ⇒ Object

Gets the delta magnitude of the counter cache for a specific object

obj: object to calculate the counter cache name for



130
131
132
133
134
135
136
 
# File 'lib/counter_culture/counter.rb', line 130

def counter_delta_magnitude_for(obj)
  if delta_magnitude.is_a?(Proc)
    delta_magnitude.call(obj)
  else
    delta_magnitude
  end
end

#execute_now_or_after_commit(obj, &block) ⇒ Object 



325
326
327
328
329
330
331
332
333
 
# File 'lib/counter_culture/counter.rb', line 325

def execute_now_or_after_commit(obj, &block)
  execute_after_commit = @execute_after_commit.is_a?(Proc) ? @execute_after_commit.call : @execute_after_commit

  if execute_after_commit
    obj.execute_after_commit(&block)
  else
    block.call
  end
end

#first_level_relation_changed?(instance) ⇒ Boolean

Returns:

  • (Boolean) 


240
241
242
243
244
245
246
 
# File 'lib/counter_culture/counter.rb', line 240

def first_level_relation_changed?(instance)
  return true if attribute_changed?(instance, first_level_relation_foreign_key)
  if polymorphic?
    return true if attribute_changed?(instance, first_level_relation_foreign_type)
  end
  false
end

#first_level_relation_foreign_key ⇒ Object

gets the foreign key name of the relation. will look at the first level only – i.e., if passed an array will consider only its first element

relation: a symbol or array of symbols; specifies the relation

that has the counter cache column



300
301
302
303
 
# File 'lib/counter_culture/counter.rb', line 300

def first_level_relation_foreign_key
  first_relation = relation.first if relation.is_a?(Enumerable)
  relation_reflect(first_relation).foreign_key
end

#first_level_relation_foreign_type ⇒ Object 



305
306
307
308
309
 
# File 'lib/counter_culture/counter.rb', line 305

def first_level_relation_foreign_type
  return nil unless polymorphic?
  first_relation = relation.first if relation.is_a?(Enumerable)
  relation_reflect(first_relation).foreign_type
end

#foreign_key_value(obj, relation, was = false) ⇒ Object

gets the value of the foreign key on the given relation

relation: a symbol or array of symbols; specifies the relation

that has the counter cache column

was: whether to get the current or past value from ActiveRecord;

pass true to get the past value, false or nothing to get the
current value



165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
 
# File 'lib/counter_culture/counter.rb', line 165

def foreign_key_value(obj, relation, was = false)
  original_relation = relation
  relation = relation.is_a?(Enumerable) ? relation.dup : [relation]
  
  if was
    first = relation.shift
    foreign_key_value = attribute_was(obj, relation_foreign_key(first))
    klass = relation_klass(first, source: obj, was: was)
    if foreign_key_value
      value = klass.where(
        "#{klass.table_name}.#{relation_primary_key(first, source: obj, was: was)} = ?",
        foreign_key_value).first
    end
  else
    value = obj
  end
  while !value.nil? && relation.size > 0
    value = value.send(relation.shift)
  end

  return value.try(relation_primary_key(original_relation, source: obj, was: was).try(:to_sym))
end

#full_primary_key(klass) ⇒ Object

the string to pass to order() in order to sort by primary key



154
155
156
 
# File 'lib/counter_culture/counter.rb', line 154

def full_primary_key(klass)
  "#{klass.quoted_table_name}.#{klass.quoted_primary_key}"
end

#polymorphic? ⇒ Boolean

Returns:

  • (Boolean) 


256
257
258
259
260
261
262
 
# File 'lib/counter_culture/counter.rb', line 256

def polymorphic?
  is_polymorphic = relation_reflect(relation).options.key?(:polymorphic)
  if is_polymorphic && !(relation.is_a?(Symbol) || relation.length == 1)
    raise "Polymorphic associations only supported with one level"
  end
  return is_polymorphic
end

#previous_model(obj) ⇒ Object 



311
312
313
314
315
316
317
318
319
320
321
322
323
 
# File 'lib/counter_culture/counter.rb', line 311

def previous_model(obj)
  prev = obj.dup

  changes_method = ACTIVE_RECORD_VERSION >= Gem::Version.new("5.1.0") ? :saved_changes : :changed_attributes
  obj.public_send(changes_method).each do |key, value|
    old_value = ACTIVE_RECORD_VERSION >= Gem::Version.new("5.1.0") ? value.first : value
    # We set old values straight to AR @attributes variable to avoid
    # write_attribute callbacks from other gems (e.g. ArTransactionChanges)
    prev.instance_variable_get(:@attributes).write_from_user(key, old_value)
  end

  prev
end

#relation_foreign_key(relation) ⇒ Object

gets the foreign key name of the given relation

relation: a symbol or array of symbols; specifies the relation

that has the counter cache column



268
269
270
 
# File 'lib/counter_culture/counter.rb', line 268

def relation_foreign_key(relation)
  relation_reflect(relation).foreign_key
end

#relation_klass(relation, source: nil, was: false) ⇒ Object

gets the class of the given relation

relation: a symbol or array of symbols; specifies the relation

that has the counter cache column

source [optional]: the source object,

only needed for polymorphic associations,
probably only works with a single relation (symbol, or array of 1 symbol)

was: boolean

we're actually looking for the old value -- only can change for polymorphic relations



222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
 
# File 'lib/counter_culture/counter.rb', line 222

def relation_klass(relation, source: nil, was: false)
  reflect = relation_reflect(relation)
  if reflect.options.key?(:polymorphic)
    raise "Can't work out relation's class without being passed object (relation: #{relation}, reflect: #{reflect})" if source.nil?
    raise "Can't work out polymorhpic relation's class with multiple relations yet" unless (relation.is_a?(Symbol) || relation.length == 1)
    # this is the column that stores the polymorphic type, aka the class name
    type_column = reflect.foreign_type.to_sym
    # so now turn that into the class that we're looking for here
    if was
      attribute_was(source, type_column).try(:constantize)
    else
      source.public_send(type_column).try(:constantize)
    end
  else
    reflect.klass
  end
end

#relation_primary_key(relation, source: nil, was: false) ⇒ Object

gets the primary key name of the given relation

relation: a symbol or array of symbols; specifies the relation

that has the counter cache column

source: the model instance that the relationship is linked from,

only needed for polymorphic associations,
probably only works with a single relation (symbol, or array of 1 symbol)

was: boolean

we're actually looking for the old value -- only can change for polymorphic relations



281
282
283
284
285
286
287
288
289
290
291
292
 
# File 'lib/counter_culture/counter.rb', line 281

def relation_primary_key(relation, source: nil, was: false)
  reflect = relation_reflect(relation)
  klass = nil
  if reflect.options.key?(:polymorphic)
    raise "can't handle multiple keys with polymorphic associations" unless (relation.is_a?(Symbol) || relation.length == 1)
    raise "must specify source for polymorphic associations..." unless source

    return reflect.options[:primary_key] if reflect.options.key?(:primary_key)
    return relation_klass(relation, source: source, was: was).try(:primary_key)
  end
  reflect.association_primary_key(klass)
end

#relation_reflect(relation) ⇒ Object

gets the reflect object on the given relation

relation: a symbol or array of symbols; specifies the relation

that has the counter cache column



192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
 
# File 'lib/counter_culture/counter.rb', line 192

def relation_reflect(relation)
  relation = relation.is_a?(Enumerable) ? relation.dup : [relation]

  # go from one relation to the next until we hit the last reflect object
  klass = model
  while relation.size > 0
    cur_relation = relation.shift
    reflect = klass.reflect_on_association(cur_relation)
    raise "No relation #{cur_relation} on #{klass.name}" if reflect.nil?

    if relation.size > 0
      # not necessary to do this at the last link because we won't use
      # klass again. not calling this avoids the following causing an
      # exception in the now-supported one-level polymorphic counter cache
      klass = reflect.klass
    end
  end

  return reflect
end