ruby - 将类的 Ruby 数组转换为 JSON

Question

我有一个这样的 Ruby 数据结构:

class Albums
    attr_accessor :title, :url

    def initialize(title, url)
        @title = title
        @url = url
    end
end

class Albumlist < Albums
    attr_accessor :id, :albums

    def initialize(id)
        @id = id
        @albums = Array.new
    end
end

然后我制作了一个 Albumlist 数组，看起来像(使用 .inspect 方法):

[#<Albumlist:0x8db6390 @id="abc",@albums=[
     #<Albums:0x8db6098 @title="123", @url="test">,
     #<Albums:0x8db5fe4 @title="456", @url="test">
 ]>,
 #<Albumlist:0x8f4042c @id="def", @albums=[
     #<Albums:0x8f49f2c @title="Untitled Album", @url="test">
 ]>
]

我不确定这个数组看起来是否正常，但是一旦我在这个数组上使用方法 .to_json 或 JSON.generate()，我得到的是:

["#<Albumlist:0x8db6390>","#<Albumlist:0x8f4042c>"]

看起来 Ruby 返回对象实例的“引用”。我想用 JSON 格式转换这个数组，它应该看起来像

[
    {
            "id":"abc"
            "albums":[
                    {
                            "title":"123",
                            "url":"test"
                    },
                    {
                            "title":"456",
                            "url":"test"
                    }
            ]
    },
    {
            "id":"def"
            "albums":[
                    {
                            "title":"Untitled Album",
                            "url":"test"
                    }
            ]
    }
]

而且我相信我遗漏了一些东西，例如将数组转换为某种中间对象？

编辑:替代解决方案

在类 Albumlist 中定义一个 to_json 方法:

def to_json(*a)
    {
        "id" => @id,
        "albums" => @albums
    }.to_json(*a)
end

然后改用它..

Answer 1

这里有效，可能您没有在正确的时间应用该方法，让我们尝试一下，首先，将注意力集中在数组上，如下所示:

require 'rubygems'
require 'active_support/all'
class Albums
    attr_accessor :title, :url

    def initialize(title, url)
        @title = title
        @url = url
    end
end

class Albumlist < Albums
    attr_accessor :id, :albums

    def initialize(id)
        @id = id
        @albums = Array.new
    end
end

a = Albums.new("a", "www.a.com")
b = Albums.new("b", "www.b.com")
c = Albums.new("c", "www.c.com")

list_of_albums_list = Array.new
list_a = Albumlist.new(1)
list_b = Albumlist.new(2)

list_a.albums << a
list_a.albums << b
list_b.albums << c

list_of_albums_list << list_a
list_of_albums_list << list_b
puts list_of_albums_list.to_json

输出是:

[{"albums":[{"title":"a","url":"www.a.com"},{"title":"b","url":"www.b.com"}],"id":1},{"albums":[{"title":"c","url":"www.c.com"}],"id":2}]

因此该方法按预期工作。