Response code classification
4xx: Client error occurs
- 400 Bad Request: think client server error occurred, but the use of this error code can not be clear which of the following error. For example, the HTTP request is malformed
- 401 Unauthorized: user authentication information is missing or incorrect, causing the server to process the request
- 407 Proxy Authentication Required: the need to verify the request via proxy authentication information through the proxy server is not
- 403 Forbidden: understanding the meaning of server requests, but does not have permission to perform this request
- 404 Not Found: The server does not find the corresponding resource
- 410 Gone: The server does not find the corresponding resources and know exactly the location of the resource can not find permanent
- 405 Method Not Allowed: the server does not support the method of the method of the request line
- 406 Not Acceptable: the client specified resource representation is present (for example, requirements of the language or code), the server returns the list of representation for clients to choose
- 408 Request Timeout: the server receiving a request timeout
- 409 Conflict: resource conflicts, such as the target location has been updated when there is a resource file upload
- 411 Length Required: if the request contains inclusions and not carrying Content-Length header, does not belong to the chunk (chunked transfer encoding) based request, returns 411
- 412 Precondition Failed: when multiplexing transmission buffer If-Unmodified-Since or If-None-Match header is not satisfied
- 413 Payload Too Large / Request Entity Too Large: requested packet exceeds the maximum length of the body server can handle
- 414 URI Too Long: URI requested length exceeds the maximum acceptable server
- 415 Unsupported Media Type: The uploaded file type is not supported server
- 416 Range Not Satisfiable: Range can not provide that part of the package body specified in the request. For example file only 100m, but we requested file contents 1G-2G's.
- 417 Expection Failed: response code when a request for the case Expec head expectations can not be met
- 426 Upgrade Required: The server is refusing to provide services based on the current HTTP protocol, the protocol must be upgraded in order to continue processing the client informed by the head Upgrade
- 428 Precondition Required: the user requests deletion of the conditions of the head, e.g. If-Match
- 429 Too Many Request: client-initiated request rate is too fast
- 431 Request Header Fields Too Large: request header size exceeds the limit HEADER
- 451 Unavailable For Legal Reasons: RFC7725, for legal reasons resources are not accessible
5xx: server-side error occurs
- 500 Internal Server Error: Internal server error occurs, and does not belong to the following types
- 501 Not Implemented: The server does not support the achievement of the desired feature request
- 502 Bad Gateway: the proxy server can not obtain legitimate response
- 503 Service Unavailable: the server resources are not yet ready to handle the current request, such as server-side request to do the speed limit, do user IP concurrent connection limit, time limit to achieve can happen when
- 504 Gateway Timeout: the proxy server can not get a timely response from the upstream. (Too small may proxy server timeout setting)
- 505 HTTP Version Not Supported: The request HTTP protocol version does not support
- 507 Insufficient Storage: server does not have enough space to handle the request (but already storm drain internal server problem, we generally will not be seen)
- 508 Loop Detected: detected cycle (cycle has reached the maximum number of times) when accessing resources
- 511 Network Authentication Requeired: Proxy found that clients need to authenticate to get access to the network, such as airports, Internet cafes often see such a scene
所有响应码遵循的响应规则：当客户端接收到了一个它不认识的响应码，不知道如何处理时，将按照他们所在系列的100，200，300，400，500的处理逻辑。