HTTP 101 Switching Protocols vs 501 Not Implemented
HTTP 101 (Switching Protocols) is a 1xx Informational response, while 501 (Not Implemented) is a 5xx Server Error response. 101 indicates that the server understands the Upgrade header field request and indicates which protocol it is switching to. In contrast, 501 means that the server does not support the functionality required to fulfill the request. The server either does not recognize the request method or lacks the ability to fulfill it.
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 does not support the functionality required to fulfill the request. The server either does not recognize the request method or lacks the ability to fulfill it.
このコードが表示される場合
When using an HTTP method (like PATCH) that the server doesn't support.
解決方法
Use a different HTTP method that the server supports. Check server documentation.
主な違い
101 is a 1xx Informational response, while 501 is a 5xx Server Error response.
HTTP 101: The server understands the Upgrade header field request and indicates which protocol it is switching to.
HTTP 501: The server does not support the functionality required to fulfill the request. The server either does not recognize the request method or lacks the ability to fulfill it.
You encounter 101 when when upgrading from HTTP/1.1 to WebSocket, or to HTTP/2.
You encounter 501 when when using an HTTP method (like PATCH) that the server doesn't support.
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 501 (Not Implemented): Use a different HTTP method that the server supports. Check server documentation.