CGI Perl Tutorial

Status Codes and Reason Phrases

The following information is a subset of an Internet draft known as Hypertext Transfer Protocol-HTTP/1.0

The status code element is a three-digit integer result code of an attempt to understand and satisfy a request. The reason phrase is intended to give a short, textual description of the status code. The status code is intended for use by the supporting software and the reason phrase is intended for the human user. The client is not required to examine or display the reason phrase.

The first digit of the status code defines the class of response. The last two digits do not have any categorization role. There are five values for the first digit, as shown in Table C.1.

Table C.1. Status codes and meanings.

Numeric	English	Meaning
1xx	Informational	This is not used; it is reserved for future use.
2xx	Success	The action was received, understood, and accepted.
3xx	Redirection	Further action must be taken in order to complete the request.
4xx	Client Error	The request contains bad syntax or cannot be fulfilled.
5xx	Server Error	The server failed to fulfill an apparently valid request.

Table C.2 lists the individual values of the numeric status codes defined for HTTP/1.0.

Table C.2. Status codes for HTTP/1.0.

Code	Reason Field	Meaning
201	Created	The request has been fulfilled and resulted in a new resource being created. The newly created resource can be referenced by the URI(s) returned in the URI-header field of the response, with the most specific URI for the resource given by a Location header field.
202	Accepted	The request has been accepted for processing, but the processing has not been completed.
203	Non-Authoritative	The returned metainformation in the Entity-Information header is not the definitive set as available from the origin server, but is gathered from a local or a third-party copy.
204	No Content	The server has fulfilled the request, but there is no new information to send back.
300	Multiple Choices	The requested resource is available at one or more locations and a preferred location could not be determined via content negotiation.
301	Moved Permanently	The requested resource has been assigned a new, permanent URI; any future references to this resource should be done using one of the returned URIs.
302	Moved Temporarily	The requested resource resides temporarily under a different URI.
303	See Other	The requested resource resides under a different URI and should be accessed using a Get method on that resource.
304	Not Modified	If the client has performed a conditional Get request and access is allowed, but the document has not been modified since the date and time specified in the If-Modified-Since field, the server responds with this status code and does not send an Entity-Body header to the client.
400	Bad Request	The request could not be understood by the server because it has a malformed syntax.
401	Unauthorized	The request requires user authentication. The response must include a WWW-Authenticate header field containing a challenge applicable to the requested resource.
402	Payment Required	This code is not currently supported, but it is reserved for future use.
403	Forbidden	The server understood the request but is refusing to perform the request because of an unspecified reason.
404	Not Found	The server has not found anything matching the request URI.
405	Method Not Allowed	The method specified in the request line is not allowed for the resource identified by the request URI.
406	None Acceptable	The server has found a resource matching the request URI, but not one that satisfies the conditions identified by the Accept and Accept-Encoding request headers.
407	Proxy Authentication (Unauthorized) Required	This code is reserved for future use. Itis similar to 401, but it indicates that the client first must authenticate itself with the proxy. HTTP/1.0 does not provide a means for proxy authentication.
408	Request Timeout	The client did not produce a request within the time that the server was prepared to wait.
409	Conflict	The request could not be completed due to a conflict with the current state of the resource.
410	Gone	The requested resource is no longer available at the server, and no forwarding address is known.
411	Authorization Refused	The request credentials provided by the client were rejected by the server or insufficient to grant authorization to access the resource.
500	Internal Server Error	The server encountered an unexpected condition that prevented it from fulfilling the request.
501	Not Implemented	The server does not support the functionality required to fulfill the request.
502	Bad Gateway	The server received an invalid response from the gateway or upstream server it accessed when attempting to fulfill the request.
503	Service Unavailable	The server currently is unable to handle the request due to a temporary overloading or maintenance of the server.
504	Gateway Timeout	The server did not receive a timely response from the gateway or upstream server it accessed when attempting to complete the request.