[ActiveStorage :: DiskController＃update通过ActiveStorage :: DirectUploadsController上传图像时抛出422

Question

我一直在撞墙，试图弄清正在发生的事情，并感谢有经验的人的帮助。

这是怎么回事，

我正在尝试使用ActiveStorage::DirectUploadsController上传图像。这是我的自定义控制器的外观：

class DirectUploadsController < ActiveStorage::DirectUploadsController
  # Should only allow null_session in API context, so request is JSON format
  protect_from_forgery with: :null_session, if: proc { |c| c.request.format == 'application/json' }

  before_action :authenticate_request

  private

  def authenticate_request
    user = AuthorizeApiRequest.call(request.headers).result
    render json: { error: 'Not Authorized' }, status: 401 unless user
  end
end

但是，当用jpeg击中端点时，我得到以下信息：

Started POST "/direct_uploads" for ::1 at 2020-04-17 17:42:40 -0400
Processing by DirectUploadsController#create as JSON
  Parameters: {"blob"=>{"filename"=>"image_picker_1249334B-5119-4F5E-91FB-99D55063495C-37712-0000F8C231364FA5.jpg", "content_type"=>"image/jpeg", "byte_size"=>1476387, "checksum"=>"33cpsUeaiJpTT+o6MkZlAQ=="}, "direct_upload"=>{"blob"=>{"filename"=>"image_picker_1249334B-5119-4F5E-91FB-99D55063495C-37712-0000F8C231364FA5.jpg", "content_type"=>"image/jpeg", "byte_size"=>1476387, "checksum"=>"33cpsUeaiJpTT+o6MkZlAQ=="}}}
Can't verify CSRF token authenticity.
  User Load (0.5ms)  SELECT "users".* FROM "users" WHERE "users"."id" = ? LIMIT ?  [["id", 1], ["LIMIT", 1]]
  ↳ app/commands/authorize_api_request.rb:19:in `user'
   (0.1ms)  begin transaction
  ActiveStorage::Blob Create (1.5ms)  INSERT INTO "active_storage_blobs" ("key", "filename", "content_type", "byte_size", "checksum", "created_at") VALUES (?, ?, ?, ?, ?, ?)  [["key", "2qcdc5dzs615rkxf5xgptki4l5pe"], ["filename", "image_picker_1249334B-5119-4F5E-91FB-99D55063495C-37712-0000F8C231364FA5.jpg"], ["content_type", "image/jpeg"], ["byte_size", 1476387], ["checksum", "33cpsUeaiJpTT+o6MkZlAQ=="], ["created_at", "2020-04-17 21:42:41.075445"]]
   (10.2ms)  commit transaction
  Disk Storage (4.8ms) Generated URL for file at key: 2qcdc5dzs615rkxf5xgptki4l5pe (http://localhost:3000/rails/active_storage/disk/eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaDdDVG9JYTJWNVNTSWhNbkZqWkdNMVpIcHpOakUxY210NFpqVjRaM0IwYTJrMGJEVndaUVk2QmtWVU9oRmpiMjUwWlc1MFgzUjVjR1ZKSWc5cGJXRm5aUzlxY0dWbkJqc0dWRG9UWTI5dWRHVnVkRjlzWlc1bmRHaHBBeU9IRmpvTlkyaGxZMnR6ZFcxSkloMHpNMk53YzFWbFlXbEtjRlJVSzI4MlRXdGFiRUZSUFQwR093WlUiLCJleHAiOiIyMDIwLTA0LTE3VDIxOjQ3OjQxLjExMVoiLCJwdXIiOiJibG9iX3Rva2VuIn19--b2c1b25a821e7ef4b150012ad33d28e5bb6752e8)
Completed 200 OK in 439ms (Views: 1.9ms | ActiveRecord: 14.4ms | Allocations: 20173)


Started PUT "/rails/active_storage/disk/eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaDdDVG9JYTJWNVNTSWhNbkZqWkdNMVpIcHpOakUxY210NFpqVjRaM0IwYTJrMGJEVndaUVk2QmtWVU9oRmpiMjUwWlc1MFgzUjVjR1ZKSWc5cGJXRm5aUzlxY0dWbkJqc0dWRG9UWTI5dWRHVnVkRjlzWlc1bmRHaHBBeU9IRmpvTlkyaGxZMnR6ZFcxSkloMHpNMk53YzFWbFlXbEtjRlJVSzI4MlRXdGFiRUZSUFQwR093WlUiLCJleHAiOiIyMDIwLTA0LTE3VDIxOjQ3OjQxLjExMVoiLCJwdXIiOiJibG9iX3Rva2VuIn19--b2c1b25a821e7ef4b150012ad33d28e5bb6752e8" for ::1 at 2020-04-17 17:42:41 -0400
Processing by ActiveStorage::DiskController#update as HTML
  Parameters: {"encoded_token"=>"eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaDdDVG9JYTJWNVNTSWhNbkZqWkdNMVpIcHpOakUxY210NFpqVjRaM0IwYTJrMGJEVndaUVk2QmtWVU9oRmpiMjUwWlc1MFgzUjVjR1ZKSWc5cGJXRm5aUzlxY0dWbkJqc0dWRG9UWTI5dWRHVnVkRjlzWlc1bmRHaHBBeU9IRmpvTlkyaGxZMnR6ZFcxSkloMHpNMk53YzFWbFlXbEtjRlJVSzI4MlRXdGFiRUZSUFQwR093WlUiLCJleHAiOiIyMDIwLTA0LTE3VDIxOjQ3OjQxLjExMVoiLCJwdXIiOiJibG9iX3Rva2VuIn19--b2c1b25a821e7ef4b150012ad33d28e5bb6752e8"}
Completed 422 Unprocessable Entity in 1ms (ActiveRecord: 0.0ms | Allocations: 218)

看起来第一个请求成功，然后从ActiveStorage gem内部进行了内部调用，但失败。我做了一些挖掘，发现的唯一类似问题在这里：https://github.com/rails/rails/issues/34058

似乎此检查失败，导致422：https://github.com/rails/rails/blob/bfea0af4ba7d717d6a065b4370e3ccfd8869dde6/activestorage/app/controllers/active_storage/disk_controller.rb#L22-L26

[调试后，似乎此检查失败：token[:content_length] == request.content_length，因为token[:content_length]是正确的，但request.content_length是0。

我不太确定接下来要去哪里，我想我找到了请求的来源，但是根据我的判断，content_length的设置正确。知道发生了什么吗？

我正在使用以下程序包从Flutter前端发出请求：https://pub.dev/packages/active_storage/。我很想直接使用Postman测试API，但似乎找不到有关请求格式的任何信息。

Answer 1

protect_from_forgery with: :null_session, if: proc { |c| c.request.format.json? }

request.format是一个类似字符串的对象，其中包含格式（：json）的“符号”，而不是MIME类型“ application / json”，这就是为什么比较始终为假的原因。