HTTP 101 Switching Protocols vs 426 Upgrade Required
HTTP 101 (Switching Protocols) is a 1xx Informational response, while 426 (Upgrade Required) 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, 426 means that the server refuses to perform the request using the current protocol but might after the client upgrades to a different protocol.
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 refuses to perform the request using the current protocol but might after the client upgrades to a different protocol.
このコードが表示される場合
When a server requires HTTPS or a newer protocol version.
解決方法
Switch to the protocol specified in the Upgrade response header.
主な違い
101 is a 1xx Informational response, while 426 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 426: The server refuses to perform the request using the current protocol but might after the client upgrades to a different protocol.
You encounter 101 when when upgrading from HTTP/1.1 to WebSocket, or to HTTP/2.
You encounter 426 when when a server requires HTTPS or a newer protocol version.
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 426 (Upgrade Required): Switch to the protocol specified in the Upgrade response header.