BIND::Conf_Parser(3) User Contributed Perl Documentation BIND::Conf_Parser(3)NAMEBIND::Conf_Parser - Parser class for BIND configuration files
SYNOPSIS
# Should really be a subclass
use BIND::Conf_Parser;
$p = BIND::Conf_Parser->new;
$p->parse_file("/etc/named.conf");
$p->parse_fh(STDIN);
$p->parse("server 10.0.0.1 { bogus yes; };");
# For one-shot parsing
BIND::Conf_Parser->parse_file("/etc/named.conf")
BIND::Conf_Parser->parse_fh(STDIN);
BIND::Conf_Parser->parse("server 10.0.0.1 { bogus yes; };");
DESCRIPTION
"BIND::Conf_Parser" implements a virtual base class for parsing BIND
(Berkeley Internet Name Domain) server version 8 configuration files
("named.conf"). The parsing methods shown in the synopsis perform
syntactic analysis only. As each meaningful semantic 'chunk' is
parsed, a callback method is invoked with the parsed information. The
following methods are the public entry points for the base class:
$p = BIND::Conf_Parser->new
The object constructor takes no arguments.
$p->parse_file( $filename )
The given filename is parsed in its entirety.
$p->parse_fh( $fh [, $filename] )
The given filehandle is parsed in its entirety. An optional
filename may be given for inclusion in any error messages that are
generated during the parsing. If it is not included a default of
"a file handle" will be used.
$p->parse( $statements [, $filename] );
The given scalar is parsed in its entirety. Partial statements
will be treated as a syntax error. An optional filename may be
given for inclusion in any error messages that are generated during
the parsing. If it is not included a default of "a scalar" will be
used.
For conveniance, the last three methods may also be called as class
methods (that is, with the class name instead of a constructed object
reference), in which case they will call new() method and use the
resulting object. All three return the object used, whether passed in
or constructed at call-time.
In order to make the parser useful, you must make a subclass where you
override one or more of the following methods as appropriate:
$self->handle_logging_category( $name, \@names )
$self->handle_logging_channel( $name, \%options )
$self->handle_key( $name, $algo, $secret )
$self->handle_acl( $name, $addrmatchlist )
$self->handle_option( $option, $argument )
$self->handle_server( $name, \%options )
$self->handle_trusted_key( $domain, \@key_definition)
$self->handle_empty_zone( $name, $class, \%options )
$self->handle_zone( $name, $class, $type, \%options )
$self->handle_control( $socket_type, \@type_specific_data )
The exact format of the data passed to the above routines is not
currently documented outside of the source to the class, but should be
found to be fairly natural.
USAGE
A typical usage would run something like:
# Define a subclass
package Parser;
use BIND::Conf_Parser;
use vars qw(@ISA);
@ISA = qw(BIND::Conf_Parser);
# implement handle_* methods for config file statements that
# we're interested in
sub handle_option {
my($self, $option, $argument) = @_;
return unless $option eq "directory";
$named_dir = $argument;
}
sub handle_zone {
my($self, $name, $class, $type, $options) = @_;
return unless $type eq "master" && $class eq "in";
$files{$name} = $options->{file};
}
# later, back at the ranch...
package main;
Parser->parse_file("/etc/named.conf");
WARNING: if the subclass is defined at the end of the main program
source file, the assignment to @ISA may need to be wrapped in a "BEGIN"
block, ala
BEGIN {
@ISA = qw(BIND::Conf_Parser);
}
BUGS
"BIND::Conf_Parser" does not perform all the syntactic checks performed
by the parser in named itself. For example, port numbers are not
verified to be positive intergers in the range 0 to 65535.
The parse() method cannot be called multiple times with parts of
statements.
Comments are not passed to a callback method.
Some callbacks are invoked before the semicolon that terminates the
corresponding syntactic form is actually recognized. It is therefore
possible for a syntax error to not be detected until after a callback
is invoked for the presumably completly parsed form. No attempt is
made to delay the invocation of callbacks to the completion of toplevel
statements.
NOTE
This version of "BIND::Conf_Parser" corresponds to BIND version 8.2.2
and understands the statements, options, and forms of that version.
Since the BIND developers have only made upward compatible changes to
the syntax, "BIND::Conf_Parser" will correctly parse valid config files
for previous versions of BIND.
A "BIND::Conf_Parser" object is a blessed anonymous hash. In an
attempt to prevent modules trampling on each other I propose that any
subclass that requires persistant state between calls to the callback
routines (handle_foo()) and other subclass methods should prefix its
keys names with its own name separated by _'s. For example, a
hypothetical "BIND::Conf_Parser::Keys" module would keep data under
keys that started with 'bind_conf_parser_keys_', e.g.,
'bind_conf_parser_keys_key_count'. The 'state' key is reserved for use
by application specific one-shot parsers (this is expected to encompass
most uses of "BIND::Conf_Parser"). "BIND::Conf_Parser" reserves for
itself all keys beginning with an underbar.
COPYRIGHT
Copyright 1998-1999 Philip Guenther. All rights reserved.
This library is free software; you can redistribute it and/or This
program is free software; redistribution and modification in any form
is explicitly permitted provided that all versions retain this
copyright notice and the following disclaimer.
This library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
perl v5.18.1 2013-09-27 BIND::Conf_Parser(3)
