Ruby on rails 机架cors未通过精细上传器预飞

我正在尝试使用react前端的fine uploader，将其上传到rails 5后端

rack cors在我的中间产品列表中排名第二：

use Webpacker::DevServerProxy
use Rack::Cors
use Rack::Sendfile
use ActionDispatch::Static
use ActionDispatch::Executor
use ActiveSupport::Cache::Strategy::LocalCache::Middleware
use Rack::Runtime
use ActionDispatch::RequestId
use ActionDispatch::RemoteIp
use Rails::Rack::Logger
use ActionDispatch::ShowExceptions
use WebConsole::Middleware
use ActionDispatch::DebugExceptions
use ActionDispatch::Reloader
use ActionDispatch::Callbacks
use ActiveRecord::Migration::CheckPending
use Rack::Head
use Rack::ConditionalGet
use Rack::ETag
use Warden::Manager
run Project::Application.routes

当fine uploader尝试上载图像时，我进入控制台：

Failed to load http://localhost:5000/item/1374/image: Response to preflight 
request doesn't pass access control check: No 'Access-Control-Allow-Origin' 
header is present on the requested resource. Origin 'http://lvh.me:3000' is 
therefore not allowed access.

我可以看到飞行前（

选项

）http请求，其中包含以下数据：

GENERAL
Request URL:http://localhost:5000/item/1374/image
Request Method:OPTIONS
Status Code:200 OK
Remote Address:127.0.0.1:5000
Referrer Policy:no-referrer-when-downgrade

RESPONSE HEADERS:
HTTP/1.1 200 OK
Content-Type: text/plain
Transfer-Encoding: chunked

REQUEST HEADERS: 
OPTIONS /item/1374/image HTTP/1.1
Host: localhost:5000
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache
Access-Control-Request-Method: update
Origin: http://lvh.me:3000
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.186 Safari/537.36
Access-Control-Request-Headers: cache-control,x-requested-with
Accept: */*
DNT: 1
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9,it;q=0.8

这是同一调用的cors调试日志：

{"Access-Control-Allow-Origin"=>"http://lvh.me:3000", "Access-Control-Allow-Methods"=>"GET, POST, PUT, PATCH, DELETE, OPTIONS, HEAD", "Access-Control-Expose-Headers"=>"access-token, expiry, token-type, uid, client, Access-Control-Allow-Origin", "Access-Control-Max-Age"=>"1728000", "Access-Control-Allow-Credentials"=>"true"}
Incoming Headers:
  Origin: http://lvh.me:3000
  Access-Control-Request-Method: update
  Access-Control-Request-Headers: cache-control,x-requested-with
Preflight Headers:
  Content-Type: text/plain

我的

config/initializers/cors.rb

看起来像：

Rails.application.config.middleware.insert_before 0, Rack::Cors, debug: true, logger: (-> { Rails.logger }) do
  allow do
    origins 'localhost:3000',
            'http://localhost:3000',
            '127.0.0.1:3000',
            /\Ahttp:\/\/192\.168\.0\.\d{1,3}(:\d+)?\z/,
            'http://lvh.me:3000'

    resource '*',
             headers: :any,
             expose:  %w[access-token expiry token-type uid client Access-Control-Allow-Origin],
             credentials: true,
             methods: %i[get post put patch delete options head]
  end
end

我还尝试了

origin'*'

和

credentials:false

，但得到了相同的结果

---

我不明白问题出在哪里

是我的错，我请求

更新

，但只允许

放置

和

补丁

---

我把请求改成了put，现在我离walhalla又近了一步

好的，谢谢分享。请相应地编辑/更新问题。