iphone - didReceiveResponse 是否保证在 connectionDidFinishLoading 之前？

Question

背景:在握手过程中，我的 iOS 应用学习服务器能力

1. 在didReceiveResponse中查看其头信息

   和

2. 在 connectionDidFinishLoading 中解析其响应 XML>

问题陈述:由于回调 #1 在 #2 之前，我将版本字符串存储在 didReceiveResponse 中，稍后在 connectionDidFinishLoading 中检查它响应可用。

幸运的是，到目前为止它运行良好，因为 #1 在 #2 之前。但是网络/iOS 总是保证该顺序吗？

Answer 1

来自 NSURLCOnnection Reference :

Zero or more connection:didReceiveResponse: messages will be sent

to the delegate before receiving a connection:didReceiveData: message. The only case where connection:didReceiveResponse: is not sent to a delegate is when the protocol implementation encounters an error before a response could be created.

Zero or more connection:didReceiveData: messages will be sent

before any of the following messages are sent to the delegate: connection:willCacheResponse:, connectionDidFinishLoading:, connection:didFailWithError:.

Zero or one connection:willCacheResponse: messages will be sent to

the delegate after connection:didReceiveData: is sent but before a connectionDidFinishLoading: message is sent.

因此，只有在创建响应之前出现错误时才会发生这种情况。