Status codes

The values of the numeric status code toHTTP requests are as follows. The datasections of messages Error, Forward and redirection responses may be usedto contain human-readable diagnostic information.

Success 2xx

These codes indicate success. The body section if present is the object returnedby the request. It is a MIME format object. It is in MIME format, and mayonly be in text/plain, text/html or one fo the formats specified as acceptablein the request.

OK 200

The request was fulfilled.

CREATED 201

Following a POST command, this indicates success, but the textual part ofthe response line indicates the URI by which the newly created document shouldbe known.

Accepted 202

The request has been accepted for processing, but the processing has notbeen completed. The request may or may not eventually be acted upon, as itmay be disallowed when processing actually takes place. there is no facilityfor status returns from asynchronous operations such as this.

Partial Information 203

When received in the response to a GET command, this indicates that the returnedmetainformation is not a definitive set of the object from a server witha copy of the object, but is from a private overlaid web. This may includeannotation information about the object, for example.

No Response 204

Server has received the request but there is no information to send back,and the client should stay in the same document view. This is mainly to allowinput for scripts without changing the document at the same time.

Error 4xx, 5xx

The 4xx codes are intended for cases in which the client seems to have erred,and the 5xx codes for the cases in which the server is aware that the serverhas erred. It is impossible to distinguish these cases in general, so thedifference is only informational.

The body section may contain a document describing the error in human readableform. The document is in MIMEformat, and may only be in text/plain, text/html or one for the formats specifiedas acceptable in the request.

Bad request 400

The request had bad syntax or was inherently impossible to be satisfied.

Unauthorized 401

The parameter to this message gives a specification of authorization schemeswhich are acceptable. The client should retry the request with a suitableAuthorization header.

PaymentRequired 402

The parameter to this message gives a specification of charging schemesacceptable. The client may retry the request with a suitable ChargeTo header.

Forbidden 403

The request is for something forbidden. Authorization will not help.

Not found 404

The server has not found anything matching the URI given

Internal Error 500

The server encountered an unexpected condition which prevented it from fulfillingthe request.

Not implemented 501

The server does not support the facility required.

Service temporarily overloaded 502 (TO BE DISCUSSED)

The server cannot process the request due to a high load (whether HTTP servicingor other requests). The implication is that this is a temporary conditionwhich maybe alleviated at other times.

Gateway timeout 503 (TO BE DISCUSSED)

This is equivalent to Internal Error 500, but in the case of a server whichis in turn accessing some other service, this indicates that the resposefrom the other service did not return within a time that the gateway wasprepared to wait. As from the point of view of the clientand the HTTP transactionthe other service is hidden within the server, this maybe treated identicallyto Internal error 500, but has more diagnostic value.

Note: The 502 and 503 codes are new and for discussion, September19, 1994

Redirection 3xx

The codes in this section indicate action to be taken (normally automatically)by the client in order to fulfill the request.

Moved 301

The data requested has been assigned a new URI, the change is permanent.(N.B. this is an optimisation, which must, pragmatically, be included inthis definition. Browsers with link editing capabiliy should automaticallyrelink to the new reference, where possible)

The response contains one or more header lines of the form

       URI:  String CrLf

Which specify alternative addresses for the object in question. The Stringis an optional comment field. If the response is to indicate a set of variantswhich each correspond to the requested URI, then themultipart/alternative wrappingmay be used to distinguish different sets

Found 302

The data requested actually resides under a different URL, however, theredirection may be altered on occasion (when making links to these kindsof document, the browser should default to using the Udi of the redirectiondocument, but have the option of linking to the final document) as for "Forward".

The response format is the same as for Moved.

Method 303

Method:  body-section

Note: This status code is to be specified in more detail. Forthe moment it is for discussion only.

Like the found response, this suggests that the client go try another networkaddress. In this case, a different method may be used too, rather than GET.

The body-section contains the parameters to be used for the method. Thisallows a document to be a pointer to a complex query operation.

The body may be preceded by the following additional fieldsas listed.

Not Modified 304

If the client has done a conditional GET and access is allowed, but the documenthas not been modified since the date and time specified inIf-Modified-Sincefield, the server responds with a 304 status code and does not send the documentbody to the client.

Response headers are as if the client had sent a HEAD request, but limitedto only those headers which make sense in this context. This means only headersthat are relevant to cache managers and which may have changed independentlyof the document's Last-Modified date. Examples include Date , Server andExpires .

The purpose of this feature is to allow efficient updates of local cacheinformation (including relevant metainformation) without requiring the overheadof multiple HTTP requests (e.g. a HEAD followed by a GET) and minimizingthe transmittal of information already known by the requesting client (usuallya caching proxy).