Http状态码含义 朱燚:

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The following is a list of HTTP response status codes and standard associated phrases, intended to give a short textual description of the status. These status codes are specified by RFC 2616, along with additional codes (RFC 2518, RFC 2817, RFC 2295, RFC 2774, RFC 4918), some from the Distributed Authoring (WebDAV) extension. Others are unstandardised but commonly used.

The first digit of the status code specifies one of five classes of response.

Contents

• 1 1xx Informational
• 2 2xx Success
• 3 3xx Redirection
• 4 4xx Client Error
• 5 5xx Server Error
• 6 See also
• 7 References
• 8 External links

1xx Informational

Request received, continuing process.

100 Continue

This means that the server has received the request headers, and that the client should proceed to send the request body (in the case of a request for which a body needs to be sent; for example, a POST request). If the request body is large, sending it to a server when a request has already been rejected based upon inappropriate headers is inefficient. To have a server check if the request could be accepted based on the request's headers alone, a client must send Expect: 100-continue as a header in its initial request (see RFC 2616 §14.20: Expect header) and check if a 100 Continue status code is received in response before continuing (or receive 417 Expectation Failed and not continue).^[1]

101 Switching Protocols

102 Processing (WebDAV) (RFC 2518)

2xx Success

The action was successfully received, understood, and accepted.

200 OK

Standard response for HTTP successful requests.

201 Created

202 Accepted

203 Non-Authoritative Information (since HTTP/1.1)

204 No Content

205 Reset Content

206 Partial Content

Notice that a file has been partially downloaded. This is used by tools like wget to enable resuming of interrupted downloads, or split a download into multiple simultaneous streams.

207 Multi-Status (WebDAV)

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.

3xx Redirection

The client must take additional action to complete the request.

300 Multiple Choices

Indicates multiple options for the URI that the client may follow. It, for instance, could be used to present different format options for video, list files with different extensions, or word sense disambiguation.

301 Moved Permanently

This and all future requests should be directed to the given URI.

302 Found

This is the most popular redirect code, but also an example of industrial practice contradicting the standard. HTTP/1.0 specification (RFC 1945) required the client to perform a temporary redirect (the original describing phrase was "Moved Temporarily"), but popular browsers implemented it as a 303 See Other. Therefore, HTTP/1.1 added status codes 303 and 307 to disambiguate between the two behaviors. However, the majority of Web applications and frameworks still use the 302 status code as if it were the 303.

303 See Other (since HTTP/1.1)

The response to the request can be found under another URI using a GET method.

304 Not Modified

Indicates the request URL has not been modified since last requested. Typically, the HTTP client provides a header like the If-Modified-Since header to provide a time with which to compare against. Utilizing this saves bandwidth and reprocessing on both the server and client.

305 Use Proxy (since HTTP/1.1)

Many HTTP clients (such as Mozilla [1] and Internet Explorer) don't correctly handle responses with this status code, primarily for security reasons.

306 Switch Proxy

No longer used.

307 Temporary Redirect (since HTTP/1.1)

In this occasion, the request should be repeated with another URI, but future requests can still be directed to the original URI. In contrast to 303, the request method should not be changed when reissuing the original request. For instance, a POST request must be repeated using another POST request.

4xx Client Error

400 Bad Request

The request contains bad syntax or cannot be fulfilled.

401 Unauthorized

Similar to 403 Forbidden, but specifically for use when authentication is possible but has failed or not yet been provided. See Basic access authentication and Digest access authentication.

402 Payment Required

The original intention was that this code might be used as part of some form of digital cash or micropayment scheme, but that has not happened, and this code has never been used.

403 Forbidden

The request was a legal request, but the server is refusing to respond to it. Unlike a 401 Unauthorized response, authenticating will make no difference.

404 Not Found

405 Method Not Allowed

A request was made to a URL using a request method not supported by that URL; for example, using GET on a form which requires data to be presented via POST, or using PUT on a read-only resource

406 Not Acceptable

407 Proxy Authentication Required

408 Request Timeout

409 Conflict

410 Gone

Indicates that the resource requested is no longer available and will not be available again. This should be used when a resource has been intentionally removed; however, in practice, a 404 Not Found is often issued instead.

411 Length Required

412 Precondition Failed

413 Request Entity Too Large

414 Request-URI Too Long

415 Unsupported Media Type

416 Requested Range Not Satisfiable

417 Expectation Failed

422 Unprocessable Entity (WebDAV) (RFC 4918)

The request was well-formed but was unable to be followed due to semantic errors.

423 Locked (WebDAV) (RFC 4918)

The resource that is being accessed is locked

424 Failed Dependency (WebDAV) (RFC 4918)

The request failed due to failure of a previous request (e.g. a PROPPATCH).

425 Unordered Collection

Defined in drafts of WebDav Advanced Collections, but not present in "Web Distributed Authoring and Versioning (WebDAV) Ordered Collections Protocol" (RFC 3648).

426 Upgrade Required (RFC 2817)

The client should switch to TLS/1.0.

449 Retry With

A Microsoft extension: The request should be retried after doing the appropriate action.

5xx Server Error

The server failed to fulfill an apparently valid request.

500 Internal Server Error

501 Not Implemented

502 Bad Gateway

503 Service Temporarily Unavailable

504 Gateway Timeout

505 HTTP Version Not Supported

506 Variant Also Negotiates (RFC 2295)

507 Insufficient Storage (WebDAV) (RFC 4918)

509 Bandwidth Limit Exceeded

This status code, while used by many servers, is not an official HTTP status code.

510 Not Extended (RFC 2774)