15.2. Status Codes
The HTTP/1.1 standard (see the
demonstration CD-ROM) defines many status codes that can be returned
as a response to a request. Most of the functions involved in
processing a request return OK,
DECLINED, or a status code.
DECLINED generally means that the module is not
interested in processing the request; OK means it
did process it, or that it is happy for the request to proceed,
depending on which function was called. Generally, a status code is
simply returned to the user agent, together with any headers defined
in the request structure's headers_out
table. At the time of writing, the status codes predefined in
httpd.h were as follows:
#define HTTP_CONTINUE 100
#define HTTP_SWITCHING_PROTOCOLS 101
#define HTTP_OK 200
#define HTTP_CREATED 201
#define HTTP_ACCEPTED 202
#define HTTP_NON_AUTHORITATIVE 203
#define HTTP_NO_CONTENT 204
#define HTTP_RESET_CONTENT 205
#define HTTP_PARTIAL_CONTENT 206
#define HTTP_MULTIPLE_CHOICES 300
#define HTTP_MOVED_PERMANENTLY 301
#define HTTP_MOVED_TEMPORARILY 302
#define HTTP_SEE_OTHER 303
#define HTTP_NOT_MODIFIED 304
#define HTTP_USE_PROXY 305
#define HTTP_BAD_REQUEST 400
#define HTTP_UNAUTHORIZED 401
#define HTTP_PAYMENT_REQUIRED 402
#define HTTP_FORBIDDEN 403
#define HTTP_NOT_FOUND 404
#define HTTP_METHOD_NOT_ALLOWED 405
#define HTTP_NOT_ACCEPTABLE 406
#define HTTP_PROXY_AUTHENTICATION_REQUIRED 407
#define HTTP_REQUEST_TIME_OUT 408
#define HTTP_CONFLICT 409
#define HTTP_GONE 410
#define HTTP_LENGTH_REQUIRED 411
#define HTTP_PRECONDITION_FAILED 412
#define HTTP_REQUEST_ENTITY_TOO_LARGE 413
#define HTTP_REQUEST_URI_TOO_LARGE 414
#define HTTP_UNSUPPORTED_MEDIA_TYPE 415
#define HTTP_INTERNAL_SERVER_ERROR 500
#define HTTP_NOT_IMPLEMENTED 501
#define HTTP_BAD_GATEWAY 502
#define HTTP_SERVICE_UNAVAILABLE 503
#define HTTP_GATEWAY_TIME_OUT 504
#define HTTP_VERSION_NOT_SUPPORTED 505
#define HTTP_VARIANT_ALSO_VARIES 506
For backward compatibility, these are also defined:
#define DOCUMENT_FOLLOWS HTTP_OK
#define PARTIAL_CONTENT HTTP_PARTIAL_CONTENT
#define MULTIPLE_CHOICES HTTP_MULTIPLE_CHOICES
#define MOVED HTTP_MOVED_PERMANENTLY
#define REDIRECT HTTP_MOVED_TEMPORARILY
#define USE_LOCAL_COPY HTTP_NOT_MODIFIED
#define BAD_REQUEST HTTP_BAD_REQUEST
#define AUTH_REQUIRED HTTP_UNAUTHORIZED
#define FORBIDDEN HTTP_FORBIDDEN
#define NOT_FOUND HTTP_NOT_FOUND
#define METHOD_NOT_ALLOWED HTTP_METHOD_NOT_ALLOWED
#define NOT_ACCEPTABLE HTTP_NOT_ACCEPTABLE
#define LENGTH_REQUIRED HTTP_LENGTH_REQUIRED
#define PRECONDITION_FAILED HTTP_PRECONDITION_FAILED
#define SERVER_ERROR HTTP_INTERNAL_SERVER_ERROR
#define NOT_IMPLEMENTED HTTP_NOT_IMPLEMENTED
#define BAD_GATEWAY HTTP_BAD_GATEWAY
#define VARIANT_ALSO_VARIES HTTP_VARIANT_ALSO_VARIES
Details of the meaning of these codes are left to the HTTP/1.1
specification, but there are a couple worth mentioning here.
HTTP_OK (formerly known as
DOCUMENT_FOLLOWS) should not normally be used,
because it aborts further processing of the request.
HTTP_MOVED_TEMPORARILY (formerly known as
REDIRECT) causes the browser to go to the URL
specified in the Location header.
HTTP_NOT_MODIFIED (formerly known as
USE_LOCAL_COPY) is used in response to a header
that makes a GET conditional (e.g.,
If-Modified-Since).
 |  |  | | 15. Writing Apache Modules |  | 15.3. The Module Structure |
Copyright © 2001 O'Reilly & Associates. All rights reserved.
|
