F.4 4xx Request Errors

only for RuBoard - do not distribute or recompile

F.4 4xx Request Errors

400 Bad Request

This code indicates that the server could not understand the client's request or found it to be incorrect in some way.

401 Unauthorized

This code is used when access to a resource is protected and the client did not provide valid authentication credentials. Often, the 401 response includes information that causes the user agent to prompt the user for a username and password.

402 Payment Required

This code is reserved but not yet described in the HTTP/1.1 specifications.

403 Forbidden

This code indicates that the resource cannot be accessed, regardless of any authentication credentials. For example, this happens if a directory or file is unreadable due to file permissions.

404 Not Found

This code indicates that the requested resource does not exist on the server. It may also be used in place of 403 if the server doesn't want to acknowledge that the resource exists but cannot be accessed.

405 Method Not Allowed

This code indicates that the request method is inappropriate for the given URI. The response should include a list of methods that are allowed.

406 Not Acceptable

This code is used when the client's requirements, as given in the Accept header, conflict with the server's capabilities. For example, the client may indicate it will accept a GIF image, but the server is only able to generate JPEG images.

407 Proxy Authentication Required

This code is similar to 401 but is only returned by proxies. A proxy returns a 407 message upon receipt of a client request that doesn't have valid authentication credentials.

408 Request Time-out

This code is used when a server times out waiting for the client's request.

409 Conflict

This code indicates that the server's resource is in a state of conflict, such that it cannot satisfy the request. Presumably, the user will be able to resolve the conflict after receiving this response.

410 Gone

This code is used when an origin server knows that the requested resource has been permanently removed.

411 Length Required

This code is used when the server requires, but did not receive, a Content-length header in the client's request. Requests for some methods, such as POST and PUT, have message bodies by default and therefore require Content-length headers.

412 Precondition Failed

This code indicates that the request was unsuccessful because one of the client's conditions was not met. For example, the client can tell the server, "Only update this resource if the current version is X." If the current version is not X, the server returns a 412 response.

413 Request Entity Too Large

This code is used when a client's request is larger than the server is willing to accept.

414 Request-URI Too Large

This code indicates that the requested URI exceeds the server's limits. Although servers should accept URIs of any length, practical considerations may require actual limits.

415 Unsupported Media Type

This code is returned when a server refuses a request because the message body is in an inappropriate format.

416 Requested Range Not Satisfiable

This code indicates that the server could not process the client's partial GET request.

417 Expectation Failed

This code indicates that the client's expectation, given in an Expect header, cannot be met. HTTP/1.1 clients typically use the Expect header to tell the server they expect to receive a 100 (Continue) status line.

only for RuBoard - do not distribute or recompile