如何使用 rack-cors 在 Access-Control-Expose-Headers 标头中声明 Content-Range

Question

为了从前端访问我的 api，它要求我在 Access-Control-Expose-Headers 标头中声明 Content-Range。我不知道具体怎么写。

Rails.application.config.middleware.insert_before 0, Rack::Cors do
  allow do
    origins '*'

    resource '*',
      headers: ["Access-Control-Expose-Headers", "Content-Range: 0-24/319"], 
      methods: [:get, :post, :put, :patch, :delete, :options, :head]
  end
end

或

Rails.application.config.middleware.insert_before 0, Rack::Cors do
  allow do
    origins '*'
    resource '*',
      headers: :any, 
      expose: ["Content-Range: orders 0-24/319"],
      methods: [:get, :post, :put, :patch, :delete, :options, :head]
  end
end

知道我写错了什么吗？

Answer 1

根据原始仓库中的test case 不可能在路由定义中传递 key: value 对 rack-cors 会接受的

Rails.application.config.middleware.insert_before 0, Rack::Cors do
  allow do
    origins '*'
    resource '*',
      headers: :any, 
      expose: ["Content-Range"],
      methods: [:get, :post, :put, :patch, :delete, :options, :head]
  end
end

然后例如，您可以在BaseController 中写入默认值，然后从中继承每个控制器

class BaseController < ApplicationController
  after_action :apply_content_range_header

  protected
  def apply_content_range_header
    response.headers['Content-Range'] = 'orders 0-24/319'
  end
end

然后在你的控制器中调用它

class ProductsController < BaseController
  def index; end # your products#index will have Content-Range header
end