如何将JSON文件解析为Ruby对象？

Question

我试图制作一个函数，从JSON文件中读取并将其解析为一个对象，给定的rspec如下，但它给了我这个错误。

NoMethodError:undefined method `from_json' for Recipe:Class

这是librecipe. rb:

require 'json'

class Recipe
  attr_accessor :title, :description, :ingredients, :cook_time, :featured

  def initialize(title:, description:, ingredients:, cook_time:, featured:)
    @title = title
    @description = description
    @ingredients = ingredients
    @cook_time = cook_time
    @featured = featured 
  end

  def from_json(file)
    recipe = JSON.parse(json)
    Recipe.new(recipe)
  end
end

而我的rspec:

 it 'Converts a json into an objeto from recipe type' do
recipe = Recipe.from_json('data/pudim.json')

    expect(recipe.class).to eq Recipe
    expect(recipe.title).to eq 'Pudim'
    expect(recipe.description).to eq 'O melhor pudim da sua vida!'
    expect(recipe.ingredients).to eq 'Leite condensado, ovos e leite'
    expect(recipe.cook_time).to eq 80
    expect(recipe.featured).to eq true
  end

这是datapudim.json:

{
  "title": "Pudim",
  "description": "O melhor pudim da sua vida!",
  "ingredients": "Leite condensado, ovos e leite",
  "cook_time": 80,
  "featured": true
}

Answer 1

看起来你试图调用一个类方法，但你的类中有一个实例方法。

考虑到这一点，你可以尝试将这个方法改为 "from_json"。self.from_json(file).