AppConfig::File
AppConfig::File(3) User Contributed Perl Documentation AppConfig::File(3)
NAME
AppConfig::File - Perl5 module for reading configuration files.
SYNOPSIS
use AppConfig::File;
my $state = AppConfig::State->new(\%cfg1);
my $cfgfile = AppConfig::File->new($state, $file);
$cfgfile->parse($file); # read config file
OVERVIEW
AppConfig::File is a Perl5 module which reads configuration files and
use the contents therein to update variable values in an AppCon-
fig::State object.
AppConfig::File is distributed as part of the AppConfig bundle.
DESCRIPTION
USING THE AppConfig::File MODULE
To import and use the AppConfig::File module the following line should
appear in your Perl script:
use AppConfig::File;
AppConfig::File is used automatically if you use the AppConfig module
and create an AppConfig::File object through the file() method.
AppConfig::File is implemented using object-oriented methods. A new
AppConfig::File object is created and initialised using the AppCon-
fig::File->new() method. This returns a reference to a new AppCon-
fig::File object. A reference to an AppConfig::State object should be
passed in as the first parameter:
my $state = AppConfig::State->new();
my $cfgfile = AppConfig::File->new($state);
This will create and return a reference to a new AppConfig::File
object.
READING CONFIGURATION FILES
The "parse()" method is used to read a configuration file and have the
contents update the STATE accordingly.
$cfgfile->parse($file);
Multiple files maye be specified and will be read in turn.
$cfgfile->parse($file1, $file2, $file3);
The method will return an undef value if it encounters any errors
opening the files. It will return immediately without processing any
further files. By default, the PEDANTIC option in the AppCon-
fig::State object, $self->{ STATE }, is turned off and any parsing
errors (invalid variables, unvalidated values, etc) will generated
warnings, but not cause the method to return. Having processed all
files, the method will return 1 if all files were processed without
warning or 0 if one or more warnings were raised. When the PEDANTIC
option is turned on, the method generates a warning and immediately
returns a value of 0 as soon as it encounters any parsing error.
Variables values in the configuration files may be expanded depending
on the value of their EXPAND option, as determined from the App::State
object. See AppConfig::State for more information on variable expan-
sion.
CONFIGURATION FILE FORMAT
A configuration file may contain blank lines and comments which are
ignored. Comments begin with a ’#’ as the first character on a line
or following one or more whitespace tokens, and continue to the end of
the line.
# this is a comment
foo = bar # so is this
url = index.html#hello # this too, but not the ’#welcome’
Notice how the ’#welcome’ part of the URL is not treated as a comment
because a whitespace character doesn’t precede it.
Long lines can be continued onto the next line by ending the first
line with a ’\’.
callsign = alpha bravo camel delta echo foxtrot golf hipowls \
india juliet kilo llama mike november oscar papa \
quebec romeo sierra tango umbrella victor whiskey \
x-ray yankee zebra
Variables that are simple flags and do not expect an argument
(ARGCOUNT = ARGCOUNT_NONE) can be specified without any value. They
will be set with the value 1, with any value explicitly specified
(except "0" and "off") being ignored. The variable may also be speci-
fied with a "no" prefix to implicitly set the variable to 0.
verbose # on (1)
verbose = 1 # on (1)
verbose = 0 # off (0)
verbose off # off (0)
verbose on # on (1)
verbose mumble # on (1)
noverbose # off (0)
Variables that expect an argument (ARGCOUNT = ARGCOUNT_ONE) will be
set to whatever follows the variable name, up to the end of the cur-
rent line. An equals sign may be inserted between the variable and
value for clarity.
room = /home/kitchen
room /home/bedroom
Each subsequent re-definition of the variable value overwrites the
previous value.
print $config->room(); # prints "/home/bedroom"
Variables may be defined to accept multiple values (ARGCOUNT =
ARGCOUNT_LIST). Each subsequent definition of the variable adds the
value to the list of previously set values for the variable.
drink = coffee
drink = tea
A reference to a list of values is returned when the variable is
requested.
my $beverages = $config->drinks();
print join(", ", @$beverages); # prints "coffee, tea"
Variables may also be defined as hash lists (ARGCOUNT =
ARGCOUNT_HASH). Each subsequent definition creates a new key and
value in the hash array.
alias l="ls -CF"
alias h="history"
A reference to the hash is returned when the variable is requested.
my $aliases = $config->alias();
foreach my $k (keys %$aliases) {
print "$k => $aliases->{ $k }\n";
}
A large chunk of text can be defined using Perl’s "heredoc" quoting
style.
scalar = <<BOUNDARY_STRING
line 1
line 2: Space/linebreaks within a HERE document are kept.
line 3: The last linebreak (\n) is stripped.
BOUNDARY_STRING
hash key1 = <<’FOO’
* Quotes ([’"]) around the boundary string are simply ignored.
* Whether the variables in HERE document are expanded depends on
the EXPAND option of the variable or global setting.
FOO
hash = key2 = <<"_bar_"
Text within HERE document are kept as is.
# comments are treated as a normal text.
The same applies to line continuation. \
_bar_
Note that you cannot use HERE document as a key in a hash or a name of
a variable.
The ’-’ prefix can be used to reset a variable to its default value
and the ’+’ prefix can be used to set it to 1
-verbose
+debug
Variable, environment variable and tilde (home directory) expansions
Variable values may contain references to other AppConfig variables,
environment variables and/or users’ home directories. These will be
expanded depending on the EXPAND value for each variable or the GLOBAL
EXPAND value.
Three different expansion types may be applied:
bin = ~/bin # expand ’~’ to home dir if EXPAND_UID
tmp = ~abw/tmp # as above, but home dir for user ’abw’
perl = $bin/perl # expand value of ’bin’ variable if EXPAND_VAR
ripl = $(bin)/ripl # as above with explicit parens
home = ${HOME} # expand HOME environment var if EXPAND_ENV
See AppConfig::State for more information on expanding variable val-
ues.
The configuration files may have variables arranged in blocks. A
block header, consisting of the block name in square brackets, intro-
duces a configuration block. The block name and an underscore are
then prefixed to the names of all variables subsequently referenced in
that block. The block continues until the next block definition or to
the end of the current file.
[block1]
foo = 10 # block1_foo = 10
[block2]
foo = 20 # block2_foo = 20
AUTHOR
Andy Wardley, <abw@wardley.org>
COPYRIGHT
Copyright (C) 1997-2007 Andy Wardley. All Rights Reserved.
This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
SEE ALSO
AppConfig, AppConfig::State
perl v5.8.8 2007-05-30 AppConfig::File(3)
