在 Rails 中创建唯一令牌的最佳方法? [英] Best way to create unique token in Rails?

问题描述

这是我正在使用的.不一定非要听到令牌才能猜测，它更像是一个简短的 url 标识符，而不是其他任何东西，我想保持简短.我已经按照我在网上找到的一些示例进行操作，如果发生冲突，我认为下面的代码将重新创建令牌，但我不确定.不过，我很想看到更好的建议，因为这感觉有点粗糙.

Here's what I'm using. The token doesn't necessarily have to be heard to guess, it's more like a short url identifier than anything else, and I want to keep it short. I've followed some examples I've found online and in the event of a collision, I think the code below will recreate the token, but I'm not real sure. I'm curious to see better suggestions, though, as this feels a little rough around the edges.

def self.create_token
    random_number = SecureRandom.hex(3)
    "1X#{random_number}"

    while Tracker.find_by_token("1X#{random_number}") != nil
      random_number = SecureRandom.hex(3)
      "1X#{random_number}"
    end
    "1X#{random_number}"
  end

我的令牌数据库列是一个唯一索引，我也在模型上使用 validates_uniqueness_of :token，但因为这些是根据用户在应用程序中的操作自动分批创建的(他们下订单并购买代币，本质上)，让应用抛出错误是不可行的.

My database column for the token is a unique index and I'm also using validates_uniqueness_of :token on the model, but because these are created in batches automatically based on a user's actions in the app (they place an order and buy the tokens, essentially), it's not feasible to have the app throw an error.

我想，为了减少冲突的可能性，我还可以在末尾附加另一个字符串，根据时间生成的内容或类似的内容，但我不希望令牌变得太长.

I could also, I guess, to reduce the chance of collisions, append another string at the end, something generated based on the time or something like that, but I don't want the token to get too long.

推荐答案

-- 更新 --

截至 2015 年 1 月 9 日.该解决方案现已在 Rails 5 中实施 ActiveRecord 的安全令牌实现.

As of January 9th, 2015. the solution is now implemented in Rails 5 ActiveRecord's secure token implementation.

-- Rails 4 &3 --

仅供将来参考，创建安全的随机令牌并确保模型的唯一性(使用 Ruby 1.9 和 ActiveRecord 时):

Just for future reference, creating safe random token and ensuring it's uniqueness for the model (when using Ruby 1.9 and ActiveRecord):

class ModelName < ActiveRecord::Base

  before_create :generate_token

  protected

  def generate_token
    self.token = loop do
      random_token = SecureRandom.urlsafe_base64(nil, false)
      break random_token unless ModelName.exists?(token: random_token)
    end
  end

end

@kain 建议，我同意，替换 begin...end...whilecode> with loop do...break until...end 在这个答案中，因为以前的实现可能会在未来被删除.

@kain suggested, and I agreed, to replace begin...end..while with loop do...break unless...end in this answer because previous implementation might get removed in the future.

编辑 2:

对于 Rails 4 和关注点，我建议将其移至关注点.

With Rails 4 and concerns, I would recommend moving this to concern.

# app/models/model_name.rb
class ModelName < ActiveRecord::Base
  include Tokenable
end

# app/models/concerns/tokenable.rb
module Tokenable
  extend ActiveSupport::Concern

  included do
    before_create :generate_token
  end

  protected

  def generate_token
    self.token = loop do
      random_token = SecureRandom.urlsafe_base64(nil, false)
      break random_token unless self.class.exists?(token: random_token)
    end
  end
end

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