[英]Stack level too deep
Hello I am received a "Stack level too deep" error and I am fairly sure that it is being generated from this model. 您好我收到了“Stack level too deep”错误,我很确定它是从这个模型生成的。 I know it has something to do with a recursive call, but I have thus far been unable to locate it, thanks. 我知道它与递归调用有关,但到目前为止我无法找到它,谢谢。
class Character < ActiveRecord::Base
# Associations
belongs_to :user
# Validations
validates :name, :presence => true, :uniqueness => true, :length =>
{ minimum: 2, maximum: 20 }, format: { with: /\A[a-zA-Z]+\Z/ }
validates :race, :presence => true
validates :class, :presence => true
validates :user, :presence => true
def self.races
["Human", "Dwarf", "Elven", "Orc", "Undead", "Demon"]
end
def self.classes
{
:fighter => {strength: 4, endurance: 3, dexterity: -2, charisma: -2, wisdom: -2, intelligence: -3},
:thief => {strength: -3,endurance: 2, dexterity: 4, charisma: 2, wisdom: -2, intelligence: 0},
:magi => {strength: -3, endurance: -2, dexterity: -2, charisma: 2, wisdom: 3, intelligence: -3},
:ranger => {strength: -2, endurance: 2, dexterity: 2, charisma: 0, wisdom: -3, intelligence: 0},
:cleric => {strength: 2,endurance: 2, dexterity: -3, charisma: -2, wisdom: 3, intelligence: 2}
}
end
def set_class(_class)
_attributes = Character.classes[_class.downcase]
transaction do
self.class = _class.downcase
_attributes.each do |name, value|
self.name += value
end
self.save
end
end
end
Server log: 服务器日志:
Started GET "/characters/new" for 127.0.0.1 at 2014-04-04 01:54:14 +0200
[1m[36mActiveRecord::SchemaMigration Load (0.8ms)[0m [1mSELECT "schema_migrations".* FROM "schema_migrations"[0m
Processing by CharactersController#new as HTML
[1m[35mUser Load (1.5ms)[0m SELECT "users".* FROM "users" WHERE "users"."id" = 1 ORDER BY "users"."id" ASC LIMIT 1
Rendered shared/_error_messages.html.erb (3.8ms)
Rendered characters/new.html.erb within layouts/application (38.1ms)
Completed 500 Internal Server Error in 199ms
SystemStackError - stack level too deep: SystemStackError - 堆栈级别太深:
activerecord (4.0.2) lib/active_record/attribute_methods/read.rb:85:in `'
There are three problems with your code: 您的代码有三个问题:
class
as an attribute, 你正在使用class
作为属性, :symbols
and "String".downcase
, 你很困惑:symbols
和"String".downcase
, self.name
(attribute) thinking it's a different setter. 你正在使用self.name
(属性)认为它是一个不同的setter。 Don't use class
. 不要class
。 It's a reserved keyword. 这是一个保留的关键字。
These lines will leave ruby very confused: 这些线条会让ruby非常困惑:
validates :class, :presence => true
self.class = _class.downcase
Also, I assume that you have a class
column in your DB table. 另外,我假设您的数据库表中有一个class
列。 You should really rename it to something like character_class
or rpg_class
. 您应该将其重命名为character_class
或rpg_class
。
Your self.classes
method returns a Hash
whose keys are symbols. 您的self.classes
方法返回一个Hash
其键是符号。 And yet, later you try to access it using a string: 然而,稍后您尝试使用字符串访问它:
_attributes = Character.classes[_class.downcase]
While it's true that :foobar.downcase
will do nothing, you can't access those values with "Foobar".downcase
. 虽然确实如此:foobar.downcase
什么都不做,你不能用"Foobar".downcase
访问这些值。
To fix that, you could: 要解决这个问题,您可以:
Character.classes[_class.to_sym]
使用Character.classes[_class.to_sym]
HashWithIndifferentAccess
使用HashWithIndifferentAccess
In any case, that method could be improved by using memoization . 无论如何,可以通过使用memoization来改进该方法。
At the moment you are re-creating a hash of hashes with each call. 目前,您正在为每次调用重新创建哈希哈希值。 Instead, you can save it in a variable and create it only the first time. 相反,您可以将其保存在变量中,并仅在第一次创建它。
def self.classes
@char_classes ||= { fighter: { #...
end
Or, even better, use a constant: 或者,更好的是,使用常量:
CHAR_CLASSES = { #.....
def self.classes
CHAR_CLASSES
end
I see that you have this validation in place: 我看到你已经有了这个验证:
validates :name, :presence => true, :uniqueness => true, :length => { minimum: 2, maximum: 20 }, format: { with: /\A[a-zA-Z]+\Z/ }
which means you have a name
column in your DB table, and that it's supposed to be a String
matching a specific format (only letters, between 2 and 20). 这意味着你的数据库表中有一个name
列,它应该是一个匹配特定格式的String
(只有2到20之间的字母)。
With this said, let's have a look at this block of code: 有了这个,让我们来看看这段代码:
_attributes.each do |name, value|
self.name += value
end
In this local scope, name
is a variable holding a Symbol
(eg :strength
) and value
is a Fixnum
. 在此局部范围中, name
是一个包含Symbol
的变量(例如:strength
), value
是一个Fixnum
。
When you do self.name += value
, however, you are assigning the Fixnum
to the object attribute name
. 但是,当您执行self.name += value
时,您将Fixnum
分配给对象属性 name
。
I can't see where you define methods like strength=
or dexterity=
. 我看不到你在哪里定义像strength=
或dexterity=
。 I'm assuming they are columns on the table. 我假设他们是桌上的专栏。
In that case, then this should work: 在那种情况下,这应该工作:
self.public_send("#{name}=", value)
# or just 'send' if it's a private method
When you are setting the attributes on your character, you need to generate the setter dynamically. 在角色上设置属性时,需要动态生成setter。 You can't call a dynamic method by appending a variable. 您不能通过附加变量来调用动态方法。 name = 'mike'; self.name
name = 'mike'; self.name
will not call self.mike
. name = 'mike'; self.name
不会调用self.mike
。
def set_class(_class)
_attributes = Character.classes[_class.downcase]
transaction do
self.class = _class.downcase
_attributes.each do |name, value|
self.public_send("#{name}=", value)
end
self.save
end
end
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