HTTP Response Status Code Back
Responses are mainly grouped into five classes:
- Informational responses (
- Successful responses (
- Redirects (
- Client errors (
- Server errors (
This class of status code indicates a provisional(臨時的) response, consisting only of the
Status-Line and optional headers, and is terminated by an empty line. Since HTTP/1.0 did not define any 1xx status codes, servers must not send a 1xx response to an HTTP/1.0 client except under experimental conditions.
The Server has received the request headers and the client should proceed to send the request body (like a POST request). To have a server check the request's headers, a client must send
Expect: 100-continue as a header in its initial request and receive a
100 Continue status code in response before sending the body. The response
417 Expectation Failed indicates the request should not be continued.
101 Switching Protocols
The requester has asked the server to switch protocols and the server has agreed to do so.
102 Processing (WebDAV)
A WebDAV request may contain many sub-requests involving file operations, requiring a long time to complete the request. This code indicates that the server has received and is processing the request, but no response is available yet.
This class of status codes indicates the action requested by the client was received, understood, accepted, and processed successfully.
Standard response for successful HTTP requests.
The actual response will depend on the request method used. In a GET request, the response will contain an entity corresponding to the requested resource. In a POST request, the response will contain an entity describing or containing the result of the action.
The request has been fulfilled, resulting in the creation of a new resource.
The request has been accepted for processing, but the processing has not been completed.
203 Non-Authoritative Information (since HTTP/1.1)
The server is a transforming proxy (e.g. a Web accelerator) that received a 200 OK from its origin, but is returning a modified version of the origin's response.
204 No Content
The server successfully processed the request and is not returning any content.
205 Reset Content
The server successfully processed the request, but is not returning any content. Unlike a 204 response, this response requires that the requester reset the document view.
206 Partial Content
The server is delivering only part of the resource (byte serving) due to a range header sent by the client. The range header is used by HTTP clients to enable resuming of interrupted downloads, or split a download into multiple simultaneous streams(同步流).
The message body that follows is an XML message and can contain a number of separate response codes, depending on how many sub-requests were made.
208 Already Reported(WebDAV)
The members of a DAV binding have already been enumerated in a previous reply to this request, and are not being included again.
226 IM Used
The server has fulfilled a request for the resource, and the response is a representation of the result of one or more instance-manipulations applied to the current instance. Many of them are used in URL Redirection.
This class of status code indicates the client must take additional action to complete the request.
300 Multiple Choices
Indicates multiple options for the resource from which the client may choose to redirect into.
301 Moved Permanently
This and all future requests should be directed to the given URI.
Indicates that the server require the client to perform a temporary redirect.
303 See Other
The response to the request can be found under another URI using a GET method. When received in response to a POST (or PUT/DELETE), the client should presume that the server has received the data and should issue a redirect with a separate GET message.
304 Not Modified (Notes)
Indicates that the resource has not been modified since the version specified by the request headers
If-None-Match. In such case, there is no need to retransmit(重發) the resource since the client still has a previously-downloaded copy.
305 Use Proxy
The requested resource is available only through a proxy, the address for which is provided in the response.
306 Switch Proxy
No longer used.
307 Temporary Redirect (Response to 302)
In this case, the request should be repeated with another URI; however, future requests should still use the original URI. In contrast to how 302 was historically implemented, the request method is not allowed to be changed when reissuing the original request.
308 Permanent Redirect (Response to 301)
The request and all future requests should be repeated using another URI.
307 and 308 parallel the behaviors of 302 and 301, but do not allow the HTTP method to change.
4xx Client Error
The 4xx class of status code is intended for situations in which the client seems to have erred.
400 Bad Request
The server cannot or will not process the request due to an apparent client error (e.g., malformed request syntax, too large size, invalid request message framing, or deceptive request routing)
403 Forbidden, but specifically for use when authentication is required and has failed or has not yet been provided. The response must include a
WWW-Authenticate header field containing a challenge applicable to the requested resource.
Notice: some sites issue 401 when an IP is banned from accessing by the server.
402 Payment Required
Reserved for future use. The original intention was that this code might be used as part of some form of digital cash or micro-payment scheme, but that has not happened, and this code is not usually used.
The request was a valid request, but the server is refusing to respond to it. The user might be logged in but does not have the necessary permissions for the resource.
404 Not Found
The requested resource could not be found but may be available in the future
405 Method Not Allowed
A request method is not supported for the requested resource; for example, a GET request on a form which requires data to be presented via POST, or a PUT request on a read-only resource.
406 Not Acceptable
The requested resource is capable of generating only content not acceptable according to the
Accept headers sent in the request.
407 Proxy Authentication Required
The client must first authenticate itself with the proxy.
408 Request Timeout
The server timed out waiting for the request.
Indicates that the request could not be processed because of conflict in the request, such as an edit conflict between multiple simultaneous updates.
Indicates that the resource requested is no longer available and will not be available again.
411 Length Required
The request did not specify the length of its content, which is required by the requested resource.
412 Precondition Failed
The server does not meet one of the preconditions that the requester put on the request.
413 Payload Too Large
The request is larger than the server is willing or able to process. Previously called "Request Entity Too Large".
414 URI Too Long
The URI provided was too long for the server to process. Often the result of too much data being encoded as a query-string of a GET request, in which case it should be converted to a POST request.
415 Unsupported Media Type
The request entity has a media type which the server or resource does not support.
416 Range Not Stasfiable
The client has asked for a portion(部分) of the file (byte serving), but the server cannot supply that portion.
417 Expectation Failed
The server cannot meet the requirements of the
Expect request-header field.
418 I'm a teapot
This code was defined in 1998 as one of the traditional IETF April Fools' jokes, in RFC 2324.
421 Misdirected Request
The request was directed at a server that is not able to produce a response.
422 Unprocessable Entity(WebDAV)
The request was well-formed but was unable to be followed due to semantic errors.
The resource that is being accessed is locked.
424 Failed Dependency(WebDAV)
The request failed due to failure of a previous request.
426 Upgrade Required
The client should switch to a different protocol such as TLS/1.0, given in the
Upgrade header field.
428 Precondition Required
The origin server requires the request to be conditional.
429 Too Many Requests
The user has sent too many requests in a given amount of time.
431 Request Header Fields Too Large
The server is unwilling to process the request because either an individual header field, or all the header fields collectively, are too large.
451 Unavailable For Legal Reasons
A server operator has received a legal demand to deny access to a resource or to a set of resources that includes the requested resource.
5xx Server Error
The server failed to fulfill an apparently valid request.
500 Internal Server Error
A generic error message, given when an unexpected condition was encountered(遭遇) and no more specific message is suitable.
501 Not Implemented
The server either does not recognize the request method, or it lacks the ability to fulfill the request. Usually this implies future availability.
502 Bad Gateway
The server was acting as a gateway or proxy and received an invalid response from the upstream server.
503 Service Unavailable
The server is currently unavailable (because it is overloaded or down for maintenance). Generally, this is a temporary state.
504 Gateway Timeout
The server was acting as a gateway or proxy and did not receive a timely response from the upstream server.
505 HTTP Version Not Supported
The server does not support the HTTP protocol version used in the request.
506 Variant Also Negotiates
Transparent content negotiation for the request results in a circular reference.
507 Insufficient Storage(WebDAV)
The server is unable to store the representation needed to complete the request.
508 Loop Detected(WebDAV)
The server detected an infinite loop while processing the request
510 Not Extended
Further extensions to the request are required for the server to fulfill it.
511 Network Authentication Required
The client needs to authenticate to gain network access. Intended for use by intercepting proxies used to control access to the network (e.g., "captive portals" used to require agreement to Terms of Service before granting full Internet access via a Wi-Fi hotspot).