=head1 NAME

Apache::Constants - Constants defined in apache header files

=head1 Synopsis

    use Apache::Constants;
    use Apache::Constants ':common';
    use Apache::Constants ':response';

=head1 Description

Server constants used by apache modules are defined in
B<httpd.h> and other header files, this module gives Perl access
to those constants.


=head1 Export Tags

=over 4

=item common

This tag imports the most commonly used constants.

 OK
 DECLINED
 DONE
 NOT_FOUND
 FORBIDDEN
 AUTH_REQUIRED
 SERVER_ERROR

=item response

This tag imports the B<common> response codes, plus these
response codes:

 DOCUMENT_FOLLOWS
 MOVED
 REDIRECT
 USE_LOCAL_COPY
 BAD_REQUEST
 BAD_GATEWAY
 RESPONSE_CODES
 NOT_IMPLEMENTED
 CONTINUE
 NOT_AUTHORITATIVE

B<CONTINUE> and B<NOT_AUTHORITATIVE> are aliases for B<DECLINED>.

=item methods

This are the method numbers, commonly used with
the Apache B<method_number> method.

 METHODS
 M_CONNECT
 M_DELETE
 M_GET
 M_INVALID
 M_OPTIONS
 M_POST
 M_PUT
 M_TRACE
 M_PATCH
 M_PROPFIND
 M_PROPPATCH
 M_MKCOL
 M_COPY
 M_MOVE
 M_LOCK
 M_UNLOCK

=item options

These constants are most commonly used with
the Apache B<allow_options> method:

 OPT_NONE
 OPT_INDEXES
 OPT_INCLUDES
 OPT_SYM_LINKS
 OPT_EXECCGI
 OPT_UNSET
 OPT_INCNOEXEC
 OPT_SYM_OWNER
 OPT_MULTI
 OPT_ALL

=item satisfy

These constants are most commonly used with
the Apache B<satisfies> method:

 SATISFY_ALL
 SATISFY_ANY
 SATISFY_NOSPEC

=item remotehost

These constants are most commonly used with
the Apache B<get_remote_host> method:

 REMOTE_HOST
 REMOTE_NAME
 REMOTE_NOLOOKUP
 REMOTE_DOUBLE_REV

=item http

This is the full set of HTTP response codes:
(NOTE: not all implemented here)

 HTTP_OK
 HTTP_MOVED_TEMPORARILY
 HTTP_MOVED_PERMANENTLY
 HTTP_METHOD_NOT_ALLOWED
 HTTP_NOT_MODIFIED
 HTTP_UNAUTHORIZED
 HTTP_FORBIDDEN
 HTTP_NOT_FOUND
 HTTP_BAD_REQUEST
 HTTP_INTERNAL_SERVER_ERROR
 HTTP_NOT_ACCEPTABLE
 HTTP_NO_CONTENT
 HTTP_PRECONDITION_FAILED
 HTTP_SERVICE_UNAVAILABLE
 HTTP_VARIANT_ALSO_VARIES

=item server

These are constants related to server version:

 MODULE_MAGIC_NUMBER
 SERVER_VERSION
 SERVER_BUILT

=item config

These are constants related to configuration directives:

 DECLINE_CMD

=item types

These are constants related to internal request types:

 DIR_MAGIC_TYPE

=item override

These constants are used to control and test the context of configuration
directives.

 OR_NONE
 OR_LIMIT
 OR_OPTIONS
 OR_FILEINFO
 OR_AUTHCFG
 OR_INDEXES
 OR_UNSET
 OR_ALL
 ACCESS_CONF
 RSRC_CONF

=item args_how

 RAW_ARGS
 TAKE1
 TAKE2
 TAKE12
 TAKE3
 TAKE23
 TAKE123
 ITERATE
 ITERATE2
 FLAG
 NO_ARGS

=back

=head1 Warnings

You should be aware of the issues relating to using constant
subroutines in Perl. For example, look at this example:

  $r->custom_response(FORBIDDEN => "File size exceeds quota.");

This will not set a custom response for C<FORBIDDEN>, but for the
string C<"FORBIDDEN">, which clearly isn't what is expected. You'll
get an error like this:

  [Tue Apr 23 19:46:14 2002] null: Argument "FORBIDDEN" isn't numeric in subroutine entry at ...

Therefore, you can avoid this by not using the hash notation for
things that don't require it.

  $r->custom_response(FORBIDDEN,  "File size exceeds quota.");

Another important note is that you should be using the correct
constants defined here, and not direct HTTP codes. For example:

  sub handler {
      return 200;
  }

Is not correct. The correct use is:

  use Apache::Constants qw(OK);
  
  sub handler {
      return OK;
  }

Also remember that C<OK != HTTP_OK>.

=head1 Maintainers

Maintainer is the person(s) you should contact with updates,
corrections and patches.

=over

=item * The L<documentation mailing list|maillist::docs-dev>

=back

=head1 Authors

=over

=item * Doug MacEachern

=item * Gisle Aas

=item * h2xs

=back

Only the major authors are listed above. For contributors see the
Changes file.

=cut