我想帮忙完成一段代码。我不知道如何解释我需要什么,所以我会一点一点地告诉你。
我有这个模型:
class Metric < ApplicationRecord
belongs_to: :post
after_save: :analysis!
# The table Metrics has the following columns:
# adverb_count
# adverb_density
# sentiment
# word_count
# letter_count
def analysis!
res = MetricService.call post.body
update! res
end
end
保存度量实例后,我需要调用一个外部服务,该服务将返回一个哈希值,其中包含可帮助我计算值的属性adverb_count
、adverb_density
、sentiment
,word_count
,最后是 letter_count
。为此,我创建了一个封装此逻辑的 MetricService
类:
class ApplicationService
def self.call(*args, &block)
new(*args, &block).call
end
end
class MetricService < ApplicationService
extend Memoist
def initiaze(text)
@text = text
end
# TODO: return the
def call
pre_analysis
# =>
# Hash containing several props
post_nalysis
# =>
# Hash containing sereral props
end
private
def pre_analysis
client.pre_analysis @text
end
memoize :pre_analysis
def post_analysis
client.post_analysis pre_analysis['id']
end
def client
SDK::Service.new ENV['API_KEY']
end
memoize :client
end
在这个类实例化之后,我调用了client
的两个方法:pre_analysis
和post_analyis
,通过这两个信息我可以最后计算属性 adverb_count、adverb_density、sentiment、word_count 和 letter_count
的值并将其返回给 Metric
。我想做的是为每个属性创建一个方法:
class MetricService < ApplicationService
# ...
def adverb_count
# use pre_analysis and post_analysis to computate this value here
end
def adverb_density
# use pre_analysis and post_analysis to computate this value here
end
def sentiment
# use pre_analysis and post_analysis to computate this value here
end
def word_count
# use pre_analysis and post_analysis to computate this value here
end
def letter_count
# use pre_analysis and post_analysis to computate this value here
end
# ...
end
在 call
方法中,我只是调用它们并返回哈希值。
根据我的研究,ROR 上的服务应该只包含一个公共(public)方法,所以我想我应该将这些属性保密。这是一个正确的假设吗?
有没有一种方法可以从 #call
构建散列,而不必单独调用这些方法中的每一个?例如:
def call
{
adverb_count: adverb_count
# etc
}
end
谢谢。
最佳答案
您可以像这样使用元编程:
# the only public method
def call
%w[adverb_count adverb_density sentiment word_count letter_count].each_with_object({}) do |method_name, result|
result[method_name] = send(method_name)
end
end
private
def adverb_count
# use pre_analysis and post_analysis to computate this value here
end
def adverb_density
# use pre_analysis and post_analysis to computate this value here
end
# and so on...
关于ruby-on-rails - 使用服务类中的计算属性构建哈希,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/58612857/