Swift：检查成功的HTTP状态代码

Question

我想查看HTTPURLResponse statusCode是否以2开头以指示成功。看看它是否在200到299之间（含200和299）是否更有意义？还是Swift有内置函数来查看HTTP状态代码是否代表成功？

也就是说，

var statusCode: Int = ..

以下哪个表达式是首选？

let success = String(statusCode).prefix(1) == "2"

let success = statusCode < 300 && statusCode >= 200

相关文档阅读

The first digit of the Status-Code defines the class of response. The
   last two digits do not have any categorization role. There are 5
   values for the first digit:

      - 1xx: Informational - Request received, continuing process

      - 2xx: Success - The action was successfully received,
        understood, and accepted

      - 3xx: Redirection - Further action must be taken in order to
        complete the request

      - 4xx: Client Error - The request contains bad syntax or cannot
        be fulfilled

      - 5xx: Server Error - The server failed to fulfill an apparently
        valid request

https://www.ietf.org/rfc/rfc2616.txt

Answer 1

您是正确的，任何介于200到299（含）之间的值都表示成功。

但是，这还不完整。 3XX响应可能意味着您还不知道请求是否成功，并且您需要按照重定向来确定真实状态。

303重定向可以导致返回404或200 OK的URI。