Id is required for update of singular resource.

Hello. In my case I send put request to /profile route. And since this resource is singular, I don't need to provide id param. But, unfortunately, it throws A key is required error if I don't provide id(it works if I provide any random value as id).

It happens because of this line of code
https://github.com/cerebris/jsonapi-resources/blob/master/lib/jsonapi/request_parser.rb#L201

Are the any specific reasons for this behaviour?

阅读 lib/jsonapi/request_parser.rb 第 201 行附近的代码，跟踪对单数资源 /profile 的 PUT 请求是如何进行解析的。重现缺少 ID 和任意 ID 的情况，然后确定当前的 key 要求是否是有意设计的。确定了预期行为及其原因，并且在行为应当改变时添加了回归测试，即视为完成。