ActiveModel Serializer - 将参数传递给序列化器 [英] ActiveModel Serializer - Passing params to serializers

问题描述

AMS 版本:0.9.7

我试图将参数传递给 ActiveModel 序列化程序，但没有任何运气.

I am trying to pass a parameter to an ActiveModel serializer without any luck.

我的(精简)控制器:

class V1::WatchlistsController < ApplicationController
  
   def index
     currency = params[:currency]
     @watchlists = Watchlist.belongs_to_user(current_user)
     render json: @watchlists, each_serializer: WatchlistOnlySerializer
   end

我的序列化器:

class V1::WatchlistOnlySerializer < ActiveModel::Serializer
  attributes :id, :name, :created_at, :market_value
  attributes :id

  
  def filter(keys)
    keys = {} if object.active == false 
    keys
  end 
  
  private

  def market_value
    # this is where I'm trying to pass the parameter
    currency = "usd"
    Balance.watchlist_market_value(self.id, currency)
  end

我正在尝试将参数 currency 从控制器传递给序列化程序以在 market_value 方法中使用(在示例中硬编码为;美元").

I am trying to pass a parameter currency from the controller to the serializer to be used in the market_value method (which in the example is hard-coded as "usd").

我已经尝试过@options 和@instance_options，但我似乎无法让它工作.不确定是否只是语法问题.

I've tried @options and @instance_options but I cant seem to get it work. Not sure if its just a syntax issue.

推荐答案

AMS 版本:0.10.6

传递给 render 的任何不为 adapter 保留的选项都可以在序列化程序中作为 instance_options 使用.

Any options passed to render that are not reserved for the adapter are available in the serializer as instance_options.

在您的控制器中:

def index
  @watchlists = Watchlist.belongs_to_user(current_user)
  render json: @watchlists, each_serializer: WatchlistOnlySerializer, currency: params[:currency]
end

然后你可以像这样在序列化器中访问它:

Then you can access it in the serializer like so:

def market_value
  # this is where I'm trying to pass the parameter
  Balance.watchlist_market_value(self.id, instance_options[:currency])
end

文档:传递任意选项到序列化程序

AMS 版本:0.9.7

不幸的是，对于此版本的 AMS，没有明确的方式将参数发送到序列化程序.但是您可以使用任何关键字来破解它，例如 :scope(正如 Jagdeep 所说)或:context 来自 以下访问者:

Unfortunately for this version of AMS, there is no clear way of sending parameters to the serializer. But you can hack this using any of the keywords like :scope (as Jagdeep said) or :context out of the following accessors:

attr_accessor :object, :scope, :root, :meta_key, :meta, :key_format, :context, :polymorphic

虽然我更喜欢 :context 而不是 :scope 来解决这个问题:

Though I would prefer :context over :scope for the purpose of this question like so:

在您的控制器中:

def index
  @watchlists = Watchlist.belongs_to_user(current_user)
  render json: @watchlists,
    each_serializer: WatchlistOnlySerializer,
    context: { currency: params[:currency] }
end

然后你可以像这样在序列化器中访问它:

Then you can access it in the serializer like so:

def market_value
  # this is where I'm trying to pass the parameter
  Balance.watchlist_market_value(self.id, context[:currency])
end

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