已经在 Rails 中设置了 Access-Control-Allow-Origin，仍然抱怨“请求的资源上不存在‘Access-Control-Allow-Origin’标头”

Question

在 Ruby on Rails API 中遇到 CORS 问题：我已经在 config/application.rb 中将 Access-Control-Allow-Origin 设置为“*”，如下面的代码所示。但是，当我的前端向后端 API 发出 GET 或 POST 请求时，我收到错误消息“请求的资源上不存在 'Access-Control-Allow-Origin' 标头。因此，不允许访问 Origin 'http://localhost:8888'。 "

require_relative 'boot'

require "rails"
# Pick the frameworks you want:
require "active_model/railtie"
require "active_job/railtie"
require "active_record/railtie"
require "action_controller/railtie"
require "action_mailer/railtie"
require "action_view/railtie"
require "action_cable/engine"
# require "sprockets/railtie"
# require "rails/test_unit/railtie"

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(*Rails.groups)

module MyapplicationApi
  class Application < Rails::Application
    # Initialize configuration defaults for originally generated Rails version.
    # config.load_defaults 5.1

    # Settings in config/environments/* take precedence over those specified here.
    # Application configuration should go into files in config/initializers
    # -- all .rb files in that directory are automatically loaded.

    # Only loads a smaller set of middleware suitable for API only apps.
    # Middleware like session, flash, cookies can be added back manually.
    # Skip views, helpers and assets when generating a new resource.
    config.api_only = true
    config.action_dispatch.default_headers = {
      'Access-Control-Allow-Origin' => '*',
      'Access-Control-Request-Method' => %w{GET POST PUT OPTIONS}.join(",")
    }
  end
end

我也尝试添加以下行但无济于事：

'Access-Control-Request-Method' => '*',
'Access-Control-Allow-Methods' => 'POST, PUT, DELETE, GET, OPTIONS',
'Access-Control-Allow-Headers' => 'Origin, X-Requested-With, Content-Type, Accept, Authorization'

感谢您的帮助！

Answer 1

你用过吗

gem 'rack-cors'

在 Gemfile 中

如果没有尝试添加这个。会有帮助的