HTTP 101 Switching Protocols vs 417 Expectation Failed
HTTP 101 (Switching Protocols) is a 1xx Informational response, while 417 (Expectation Failed) is a 4xx Client Error response. 101 indicates that the server understands the Upgrade header field request and indicates which protocol it is switching to. In contrast, 417 means that the server cannot meet the requirements of the Expect header.
説明
The server understands the Upgrade header field request and indicates which protocol it is switching to.
このコードが表示される場合
When upgrading from HTTP/1.1 to WebSocket, or to HTTP/2.
解決方法
This is normal behavior during protocol upgrades. Ensure your client supports the target protocol.
説明
The server cannot meet the requirements of the Expect header.
このコードが表示される場合
When the server doesn't support Expect: 100-continue.
解決方法
Remove the Expect header from your request.
主な違い
101 is a 1xx Informational response, while 417 is a 4xx Client Error response.
HTTP 101: The server understands the Upgrade header field request and indicates which protocol it is switching to.
HTTP 417: The server cannot meet the requirements of the Expect header.
You encounter 101 when when upgrading from HTTP/1.1 to WebSocket, or to HTTP/2.
You encounter 417 when when the server doesn't support Expect: 100-continue.
どちらをいつ使うか
For 101 (Switching Protocols): This is normal behavior during protocol upgrades. Ensure your client supports the target protocol. For 417 (Expectation Failed): Remove the Expect header from your request.