HTTP 100 Continue vs 501 Not Implemented
HTTP 100 (Continue) is a 1xx Informational response, while 501 (Not Implemented) is a 5xx Server Error response. 100 indicates that the server has received the request headers and the client should proceed to send the request body. This lets the client know it can continue with the request or abort if the headers were rejected. 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.
Descrição
The server has received the request headers and the client should proceed to send the request body. This lets the client know it can continue with the request or abort if the headers were rejected.
Quando você o vê
When a client sends an Expect: 100-continue header, the server responds with 100 before the client sends the body.
Como corrigir
This is an interim response — no fix needed. The client should continue sending the request body.
Descrição
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.
Quando você o vê
When using an HTTP method (like PATCH) that the server doesn't support.
Como corrigir
Use a different HTTP method that the server supports. Check server documentation.
Diferenças principais
100 is a 1xx Informational response, while 501 is a 5xx Server Error response.
HTTP 100: The server has received the request headers and the client should proceed to send the request body. This lets the client know it can continue with the request or abort if the headers were rejected.
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 100 when when a client sends an Expect: 100-continue header, the server responds with 100 before the client sends the body.
You encounter 501 when when using an HTTP method (like PATCH) that the server doesn't support.
Quando usar qual
For 100 (Continue): This is an interim response — no fix needed. The client should continue sending the request body. For 501 (Not Implemented): Use a different HTTP method that the server supports. Check server documentation.