Common HTTP status Codes

Request

1, the semantic error, the current request can not be understood by the server. Unless modified, the client should not submit the request repeatedly.

2, the request parameter is wrong.

401 Unauthorized

The current request requires user authentication. The response must contain a Www-authenticate information header for the requested resource to ask for user information. The client can repeatedly submit a request that contains the appropriate Authorization header information. If the current request already contains the Authorization certificate, the 401 response indicates that the certificate has been rejected by the server authentication. If the 401 response contains the same authentication query as the previous response, and the browser has tried at least one validation, the browser should show the user the entity information contained in the response, because the entity information may contain related diagnostic information. See RFC 2617.

402 Payment Required

This status code is reserved for possible future requirements.

403 Forbidden

The server has understood the request, but refuses to execute it. Unlike the 401 response, authentication does not provide any help, and the request should not be repeated. If this is not a HEAD request, and the server wants to be able to explain why the request cannot be executed, then the reason for the rejection should be described within the entity. Of course the server can also return a 404 response if it does not want the client to get any information.

404 Not Found

The request failed and the requested resource was not found on the server. No information can tell the user whether the situation is temporary or permanent. If the server knows the situation, it should use the 410 status code to tell the old resources because of some internal configuration mechanism problems, has been permanently unavailable, and there is no jump to the address. 404 This status code is widely used when the server does not want to reveal exactly why the request was rejected or if no other appropriate response is available. The most likely cause of this error is that the server side does not have this page.

405 Method not allowed

The request method specified in the request line cannot be used to request the appropriate resource. The response must return an allow header to indicate a list of request methods that the current resource can accept.

Because the Put,delete method writes to resources on the server, most Web servers do not support or do not allow the above request method under the default configuration, and 405 errors are returned for such requests.

406 Not acceptable

The content attribute of the requested resource could not satisfy the criteria in the request header, so the response entity could not be generated.

Unless this is a HEAD request, the response should return an entity that contains the most appropriate entity attributes and address lists that the user or browser can choose from. The format of the entity is determined by the media type defined in the Content-type header. The browser can make the best choice based on its format and ability. However, the specification does not define any criteria for making such automatic selections.

407 Proxy Authentication Required

Similar to the 401 response, except that the client must authenticate on the proxy server. The proxy server must return a proxy-authenticate to be used for identity questioning. The client can return a Proxy-authorization message header for verification. See RFC 2617.

408 Request Timeout

The request timed out. The client does not complete a request in the time the server is waiting to be sent. The client can submit the request again at any time without making any changes.

409 Conflict

The request could not be completed because there was a conflict between the current state of the requested resource and the request. This code is only allowed to be used in situations where the user is considered to be able to resolve the conflict and will resubmit the new request. The response should contain enough information for the user to discover the source of the conflict.

Conflicts usually occur in the processing of PUT requests. For example, in a version-checking environment, where the version information that accompanies a PUT-submitted modification request for a specific resource conflicts with one of the previous (third-party) requests, the server should return a 409 error informing the user that the request could not be completed. At this point, it is likely that the response entity will contain a diff comparison between the two conflicting versions, so that the user can resubmit the new version after merging.

410 Gone

The requested resource is no longer available on the server, and there are no known forwarding addresses. Such a situation should be considered permanent. If possible, a client with link editing should remove all references to this address after obtaining the user's permission. If the server does not know or is unsure whether the condition is permanent, then the 404 status Code should be used. Unless otherwise noted, the response is cacheable.

410 The purpose of the response is primarily to help the site administrator maintain the site, informing the user that the resource is no longer available, and that the server owner wants all remote connections that point to the resource to be deleted. Such events are common in time-limited and value-added services. Similarly, a 410 response is used to notify the client that a resource that was originally owned by a person is no longer available on the current server site. Of course, it is entirely up to the server owner to mark all permanently unavailable resources as ' 410 Gone ' and how long it will take to keep this tag.

411 Length Required

The server refuses to accept the request without defining a content-length header. After adding a valid Content-length header that indicates the body length of the request message, the client can submit the request again.

412 Precondition Failed

The server failed to satisfy one or more of these when validating the prerequisites in the header field of the request. This status code allows the client to set the prerequisites in the requested meta-information (Request header field data) when acquiring the resource, to prevent the request method from being applied to resources other than what it wants.

413 Request Entity Too Large

The server refuses to process the current request because the size of the entity data submitted by the request exceeds the scope that the server is willing or able to handle. In this case, the server can close the connection to prevent the client from continuing to send this request.

If this condition is temporary, the server should return a retry-after response header to tell the client how much time it can retry.

414 Request-uri Too Long

The requested URI length exceeds the length that the server can interpret, so the server refuses to service the request. This is rare, and the usual situations include:

A form submission that should use the Post method becomes a Get method that causes the query string to be too long.

REDIRECT uri "Black Hole", for example, each redirect takes the old Uri as part of the new URI, resulting in a long URI after several redirects.

The client is trying to exploit a security vulnerability in some servers to attack the server. This type of server uses a fixed-length buffer to read or manipulate the requested URI, and when the GET parameter exceeds a certain value, a buffer overflow may result, resulting in arbitrary code being executed [1]. A server that does not have such a vulnerability should return a 414 status code.

415 Unsupported Media Type

For the currently requested method and the requested resource, the entity submitted in the request is not a supported format in the server and therefore the request is rejected.

416 requested Range not satisfiable

If a range request header is included in the request, and any data range specified in range does not coincide with the current resource's available range, and the request does not have a If-range request header defined, the server should return a 416 status code.

If range uses a byte range, this is the case where the first byte position of all data ranges specified by the request exceeds the current resource's length. The server should also include a Content-range entity header to indicate the length of the current resource while returning a 416 status code. This response is also forbidden to use multipart/byteranges as its content-type.

417 Expectation Failed

The expected content specified in the request header Expect cannot be satisfied by the server, or the server is a proxy server, and it has obvious evidence that the contents of the Expect are not satisfied on the next node of the current route.

421There is too many connections from your Internet address

The number of connections from the current client's IP address to the server exceeds the maximum range of server licenses. Typically, the IP address here refers to the client address seen from the server (such as the user's gateway or proxy server address). In this case, the calculation of the number of connections may involve more than one end user.

422 unprocessable Entity

The request is well-formed, but cannot be responded to because of a semantic error. (RFC 4918 WebDAV)

423 Locked

The current resource is locked. (RFC 4918 WebDAV)

424 Failed Dependency

The current request failed, such as PROPPATCH, because of an error that occurred in a previous request. (RFC 4918 WebDAV)

425 Unordered Collection

Defined in the WebDAV advanced collections draft, but does not appear in the WebDAV sequence set protocol (RFC 3658).

426 Upgrade Required

The client should switch to tls/1.0. (RFC 2817)

449 Retry with

Extended by Microsoft, the representative request should be retried after the appropriate action has been performed.

This type of status code indicates that the server has an error or an abnormal state in the process of processing the request, or that the server is aware that the processing of the request cannot be completed with the current hardware and software resources. Unless this is a head request, the server should contain an explanatory information entity that interprets the current error state and whether the condition is temporary or permanent. The browser should show the user any entities that are contained in the current response.

These status codes apply to any response method.

Internal Server Error

The server encountered an unexpected condition that prevented it from completing the processing of the request. In general, this problem occurs when the source code on the server side is wrong.

501 Not implemented

The server does not support a feature that is required for the current request. When the server does not recognize the requested method and cannot support its request for any resource.

502 Bad Gateway

An invalid response was received from the upstream server when the server acting as a gateway or agent attempted to execute the request.

503 Service Unavailable

The server is currently unable to process the request due to temporary server maintenance or overloading. This situation is temporary and will be resumed after a certain period of time. If the delay time can be estimated, then the response can include a retry-after header to indicate the delay time. If this retry-after message is not given, the client should handle it in a manner that handles 500 responses.

Note: The presence of a 503 status code does not mean that the server must use it when it is overloaded. Some servers simply want to deny connections to clients.

504 Gateway Timeout

When a server acting as a gateway or agent attempts to execute a request, it fails to receive a response from the upstream server (the server that the URI identifies, such as HTTP, FTP, LDAP), or the secondary server (such as DNS).

Note: Some proxy servers return 400 or 500 errors in DNS query timeout

505 HTTP Version not supported

The server does not support or refuses to support the HTTP version used in the request. This implies that the server cannot or does not want to use the same version as the client. The response should contain an entity that describes why the version is not supported and which protocols the server supports.

506 Variant Also negotiates

Extended by the Transparent Content negotiation Protocol (RFC 2295), there is an internal configuration error on behalf of the server: The requested negotiation meta-resource is configured to use itself in transparent content negotiation, so it is not an appropriate focus in a negotiation process.

507 Insufficient Storage

The server cannot store the content necessary to complete the request. The situation is considered to be temporary. WebDAV (RFC 4918)

509 Bandwidth Limit exceeded

The server reached the bandwidth limit. This is not an official status code, but is still widely used.

510 not Extended

The policies needed to get resources are not met. (RFC 2774)

unparseable Response Headers

The source station does not return a response header, only the entity content is returned

Common HTTP status Codes