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.
Description
The server understands the Upgrade header field request and indicates which protocol it is switching to.
Quand vous le voyez
When upgrading from HTTP/1.1 to WebSocket, or to HTTP/2.
Comment résoudre
This is normal behavior during protocol upgrades. Ensure your client supports the target protocol.
Description
The server refuses to perform the request using the current protocol but might after the client upgrades to a different protocol.
Quand vous le voyez
When a server requires HTTPS or a newer protocol version.
Comment résoudre
Switch to the protocol specified in the Upgrade response header.
Différences clés
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.
Quand utiliser lequel
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.