General(3pm) User Contributed Perl Documentation General(3pm)
NAME
Config::General - Generic Config Module
SYNOPSIS
#
# the OOP way
use Config::General;
$conf = Config::General->new("rcfile");
my %config = $conf->getall;
#
# the procedural way
use Config::General qw(ParseConfig SaveConfig SaveConfigString);
my %config = ParseConfig("rcfile");
DESCRIPTION
This module opens a config file and parses its contents for you. The
new method requires one parameter which needs to be a filename. The
method getall returns a hash which contains all options and its
associated values of your config file.
The format of config files supported by Config::General is inspired by
the well known Apache config format, in fact, this module is 100%
compatible to Apache configs, but you can also just use simple
name/value pairs in your config files.
In addition to the capabilities of an Apache config file it supports
some enhancements such as here-documents, C-style comments or multiline
options.
SUBROUTINES/METHODS
new()
Possible ways to call new():
$conf = Config::General->new("rcfile");
$conf = Config::General->new(\%somehash);
$conf = Config::General->new( %options ); # see below for description of possible options
This method returns a Config::General object (a hash blessed into
"Config::General" namespace. All further methods must be used from
that returned object. see below.
You can use the new style with hash parameters or the old style
which is of course still supported. Possible parameters to new()
are:
* a filename of a configfile, which will be opened and parsed by
the parser
or
* a hash reference, which will be used as the config.
An alternative way to call new() is supplying an option- hash with
one or more of the following keys set:
-ConfigFile
A filename or a filehandle, i.e.:
-ConfigFile => "rcfile" or -ConfigFile => \$FileHandle
-ConfigHash
A hash reference, which will be used as the config, i.e.:
-ConfigHash => \%somehash
-String
A string which contains a whole config, or an arrayref
containing the whole config line by line. The parser will
parse the contents of the string instead of a file. i.e:
-String => $complete_config
it is also possible to feed an array reference to -String:
-String => \@config_lines
-AllowMultiOptions
If the value is "no", then multiple identical options are
disallowed. The default is "yes". i.e.:
-AllowMultiOptions => "yes"
see IDENTICAL OPTIONS for details.
-LowerCaseNames
If set to a true value, then all options found in the config
will be converted to lowercase. This allows you to provide
case-in-sensitive configs. The values of the options will not
lowercased.
-UseApacheInclude
If set to a true value, the parser will consider "include ..."
as valid include statement (just like the well known Apache
include statement).
It also supports apache's "IncludeOptional" statement with the
same behavior, that is, if the include file doesn't exist no
error will be thrown.
-IncludeRelative
If set to a true value, included files with a relative path
(i.e. "cfg/blah.conf") will be opened from within the location
of the configfile instead from within the location of the
script($0). This works only if the configfile has a absolute
pathname (i.e. "/etc/main.conf").
If the variable -ConfigPath has been set and if the file to be
included could not be found in the location relative to the
current config file, the module will search within -ConfigPath
for the file. See the description of -ConfigPath for more
details.
-IncludeDirectories
If set to a true value, you may specify include a directory, in
which case all files inside the directory will be loaded in
ASCII order. Directory includes will not recurse into
subdirectories. This is comparable to including a directory in
Apache-style config files.
-IncludeGlob
If set to a true value, you may specify a glob pattern for an
include to include all matching files (e.g. <<include
conf.d/*.conf>>). Also note that as with standard file
patterns, * will not match dot-files, so <<include dir/*>> is
often more desirable than including a directory with
-IncludeDirectories.
An include option will not cause a parser error if the glob
didn't return anything.
-IncludeAgain
If set to a true value, you will be able to include a sub-
configfile multiple times. With the default, false, you will
get a warning about duplicate includes and only the first
include will succeed.
Reincluding a configfile can be useful if it contains data that
you want to be present in multiple places in the data tree.
See the example under "INCLUDES".
Note, however, that there is currently no check for include
recursion.
-ConfigPath
As mentioned above, you can use this variable to specify a
search path for relative config files which have to be
included. Config::General will search within this path for the
file if it cannot find the file at the location relative to the
current config file.
To provide multiple search paths you can specify an array
reference for the path. For example:
@path = qw(/usr/lib/perl /nfs/apps/lib /home/lib);
..
-ConfigPath => \@path
-MergeDuplicateBlocks
If set to a true value, then duplicate blocks, that means
blocks and named blocks, will be merged into a single one (see
below for more details on this). The default behavior of
Config::General is to create an array if some junk in a config
appears more than once.
-MergeDuplicateOptions
If set to a true value, then duplicate options will be merged.
That means, if the same option occurs more than once, the last
one will be used in the resulting config hash.
Setting this option implies -AllowMultiOptions == false unless
you set -AllowMultiOptions explicit to 'true'. In this case
duplicate blocks are allowed and put into an array but
duplicate options will be merged.
-AutoLaunder
If set to a true value, then all values in your config file
will be laundered to allow them to be used under a -T taint
flag. This could be regarded as circumventing the purpose of
the -T flag, however, if the bad guys can mess with your config
file, you have problems that -T will not be able to stop.
AutoLaunder will only handle a config file being read from
-ConfigFile.
-AutoTrue
If set to a true value, then options in your config file, whose
values are set to true or false values, will be normalised to 1
or 0 respectively.
The following values will be considered as true:
yes, on, 1, true
The following values will be considered as false:
no, off, 0, false
This effect is case-insensitive, i.e. both "Yes" or "No" will
result in 1.
-FlagBits
This option takes one required parameter, which must be a hash
reference.
The supplied hash reference needs to define variables for which
you want to preset values. Each variable you have defined in
this hash-ref and which occurs in your config file, will cause
this variable being set to the preset values to which the value
in the config file refers to.
Multiple flags can be used, separated by the pipe character |.
Well, an example will clarify things:
my $conf = Config::General->new(
-ConfigFile => "rcfile",
-FlagBits => {
Mode => {
CLEAR => 1,
STRONG => 1,
UNSECURE => "32bit" }
}
);
In this example we are defining a variable named "Mode" which
may contain one or more of "CLEAR", "STRONG" and "UNSECURE" as
value.
The appropriate config entry may look like this:
# rcfile
Mode = CLEAR | UNSECURE
The parser will create a hash which will be the value of the
key "Mode". This hash will contain all flags which you have
pre-defined, but only those which were set in the config will
contain the pre-defined value, the other ones will be
undefined.
The resulting config structure would look like this after
parsing:
%config = (
Mode => {
CLEAR => 1,
UNSECURE => "32bit",
STRONG => undef,
}
);
This method allows the user (or, the "maintainer" of the
configfile for your application) to set multiple pre-defined
values for one option.
Please beware, that all occurrences of those variables will be
handled this way, there is no way to distinguish between
variables in different scopes. That means, if "Mode" would
also occur inside a named block, it would also parsed this way.
Values which are not defined in the hash-ref supplied to the
parameter -FlagBits and used in the corresponding variable in
the config will be ignored.
Example:
# rcfile
Mode = BLAH | CLEAR
would result in this hash structure:
%config = (
Mode => {
CLEAR => 1,
UNSECURE => undef,
STRONG => undef,
}
);
"BLAH" will be ignored silently.
-DefaultConfig
This can be a hash reference or a simple scalar (string) of a
config. This causes the module to preset the resulting config
hash with the given values, which allows you to set default
values for particular config options directly.
Note that you probably want to use this with
-MergeDuplicateOptions, otherwise a default value already in
the configuration file will produce an array of two values.
-Tie
-Tie takes the name of a Tie class as argument that each new
hash should be based off of.
This hash will be used as the 'backing hash' instead of a
standard Perl hash, which allows you to affect the way,
variable storing will be done. You could, for example supply a
tied hash, say Tie::DxHash, which preserves ordering of the
keys in the config (which a standard Perl hash won't do). Or,
you could supply a hash tied to a DBM file to save the parsed
variables to disk.
There are many more things to do in tie-land, see tie to get
some interesting ideas.
If you want to use the -Tie feature together with
-DefaultConfig make sure that the hash supplied to
-DefaultConfig must be tied to the same Tie class.
Make sure that the hash which receives the generated hash
structure (e.g. which you are using in the assignment: %hash =
$config->getall()) must be tied to the same Tie class.
Example:
use Config::General qw(ParseConfig);
use Tie::IxHash;
tie my %hash, "Tie::IxHash";
%hash = ParseConfig(
-ConfigFile => shift(),
-Tie => "Tie::IxHash"
);
-InterPolateVars
If set to a true value, variable interpolation will be done on
your config input. See Config::General::Interpolated for more
information.
-InterPolateEnv
If set to a true value, environment variables can be used in
configs.
This implies -InterPolateVars.
-AllowSingleQuoteInterpolation
By default variables inside single quotes will not be
interpolated. If you turn on this option, they will be
interpolated as well.
-ExtendedAccess
If set to a true value, you can use object oriented (extended)
methods to access the parsed config. See
Config::General::Extended for more information.
-StrictObjects
By default this is turned on, which causes Config::General to
croak with an error if you try to access a non-existent key
using the OOP-way (-ExtendedAcess enabled). If you turn
-StrictObjects off (by setting to 0 or "no") it will just
return an empty object/hash/scalar. This is valid for OOP-
access 8via AUTOLOAD and for the methods obj(), hash() and
value().
-StrictVars
By default this is turned on, which causes Config::General to
croak with an error if an undefined variable with
InterPolateVars turned on occurs in a config. Set to false
(i.e. 0) to avoid such error messages.
-SplitPolicy
You can influence the way how Config::General decides which
part of a line in a config file is the key and which one is the
value. By default it tries its best to guess. That means you
can mix equalsign assignments and whitespace assignments.
However, sometime you may wish to make it more strictly for
some reason. In this case you can set -SplitPolicy. The
possible values are: 'guess' which is the default, 'whitespace'
which causes the module to split by whitespace, 'equalsign'
which causes it to split strictly by equal sign, or 'custom'.
In the latter case you must also set -SplitDelimiter to some
regular expression of your choice. For example:
-SplitDelimiter => '\s*:\s*'
will cause the module to split by colon while whitespace which
surrounds the delimiter will be removed.
Please note that the delimiter used when saving a config
(save_file() or save_string()) will be chosen according to the
current -SplitPolicy. If -SplitPolicy is set to 'guess' or
'whitespace', 3 spaces will be used to delimit saved options.
If 'custom' is set, then you need to set -StoreDelimiter.
-SplitDelimiter
Set this to any arbitrary regular expression which will be used
for option/value splitting. -SplitPolicy must be set to
'custom' to make this work.
-StoreDelimiter
You can use this parameter to specify a custom delimiter to use
when saving configs to a file or string. You only need to set
it if you want to store the config back to disk and if you have
-SplitPolicy set to 'custom'.
However, this parameter takes precedence over whatever is set
for -SplitPolicy.
Be very careful with this parameter.
-CComments
Config::General is able to notice c-style comments (see section
COMMENTS). But for some reason you might no need this. In this
case you can turn this feature off by setting -CComments to a
false value('no', 0, 'off').
By default -CComments is turned on.
-BackslashEscape
Deprecated Option.
-SlashIsDirectory
If you turn on this parameter, a single slash as the last
character of a named block will be considered as a directory
name.
By default this flag is turned off, which makes the module
somewhat incompatible to Apache configs, since such a setup
will be normally considered as an explicit empty block, just as
XML defines it.
For example, if you have the following config:
<Directory />
Index index.awk
</Directory>
you will get such an error message from the parser:
EndBlock "</Directory>" has no StartBlock statement (level: 1, chunk 10)!
This is caused by the fact that the config chunk below will be
internally converted to:
<Directory></Directory>
Index index.awk
</Directory>
Now there is one '</Directory>' too much. The proper solution
is to use quotation to circumvent this error:
<Directory "/">
Index index.awk
</Directory>
However, a raw apache config comes without such quotes. In this
case you may consider to turn on -SlashIsDirectory.
Please note that this is a new option (incorporated in version
2.30), it may lead to various unexpected side effects or other
failures. You've been warned.
-UseApacheIfDefine
Enables support for Apache <IfDefine> ... </IfDefine>. See
-Define.
-Define
Defines the symbols to be used for conditional configuration
files. Allowed arguments: scalar, scalar ref, array ref or
hash ref.
Examples:
-Define => 'TEST'
-Define => \$testOrProduction
-Define => [qw(TEST VERBOSE)]
-Define => {TEST => 1, VERBOSE => 1}
Sample configuration:
<Logging>
<IfDefine TEST>
Level Debug
include test/*.cfg
</IfDef>
<IfDefine !TEST>
Level Notice
include production/*.cfg
</IfDefine>
</Logging>
-ApacheCompatible
Over the past years a lot of options has been incorporated into
Config::General to be able to parse real Apache configs.
The new -ApacheCompatible option now makes it possible to tweak
all options in a way that Apache configs can be parsed.
This is called "apache compatibility mode" - if you will ever
have problems with parsing Apache configs without this option
being set, you'll get no help by me. Thanks :)
The following options will be set:
UseApacheInclude = 1
IncludeRelative = 1
IncludeDirectories = 1
IncludeGlob = 1
SlashIsDirectory = 1
SplitPolicy = 'whitespace'
CComments = 0
UseApacheIfDefine = 1
Take a look into the particular documentation sections what
those options are doing.
Beside setting some options it also turns off support for
explicit empty blocks.
-UTF8
If turned on, all files will be opened in utf8 mode. This may
not work properly with older versions of Perl.
-SaveSorted
If you want to save configs in a sorted manner, turn this
parameter on. It is not enabled by default.
-NoEscape
If you want to use the data ( scalar or final leaf ) without
escaping special character, turn this parameter on. It is not
enabled by default.
-NormalizeBlock
Takes a subroutine reference as parameter and gets the current
block or blockname passed as parameter and is expected to
return it in some altered way as a scalar string. The sub will
be called before anything else will be done by the module
itself (e.g. interpolation).
Example:
-NormalizeBlock => sub { my $x = shift; $x =~ s/\s*$//; $x; }
This removes trailing whitespaces of block names.
-NormalizeOption
Same as -NormalizeBlock but applied on options only.
-NormalizeValue
Same as -NormalizeBlock but applied on values only.
getall()
Returns a hash structure which represents the whole config.
files()
Returns a list of all files read in.
save_file()
Writes the config hash back to the hard disk. This method takes one
or two parameters. The first parameter must be the filename where
the config should be written to. The second parameter is optional,
it must be a reference to a hash structure, if you set it. If you
do not supply this second parameter then the internal config hash,
which has already been parsed, will be used.
Please note that any occurrence of comments will be ignored by
getall() and thus be lost after you call this method.
You need also to know that named blocks will be converted to nested
blocks (which is the same from the perl point of view). An example:
<user hans>
id 13
</user>
will become the following after saving:
<user>
<hans>
id 13
</hans>
</user>
Example:
$conf_obj->save_file("newrcfile", \%config);
or, if the config has already been parsed, or if it didn't change:
$conf_obj->save_file("newrcfile");
save_string()
This method is equivalent to the previous save_file(), but it does
not store the generated config to a file. Instead it returns it as
a string, which you can save yourself afterwards.
It takes one optional parameter, which must be a reference to a
hash structure. If you omit this parameter, the internal config
hash, which has already been parsed, will be used.
Example:
my $content = $conf_obj->save_string(\%config);
or:
my $content = $conf_obj->save_string();
CONFIG FILE FORMAT
Lines beginning with # and empty lines will be ignored. (see section
COMMENTS!) Spaces at the beginning and the end of a line will also be
ignored as well as tabulators. If you need spaces at the end or the
beginning of a value you can surround it with double quotes. An option
line starts with its name followed by a value. An equal sign is
optional. Some possible examples:
user max
user = max
user max
If there are more than one statements with the same name, it will
create an array instead of a scalar. See the example below.
The method getall returns a hash of all values.
BLOCKS
You can define a block of options. A block looks much like a block in
the wellknown Apache config format. It starts with <blockname> and ends
with </blockname>.
A block start and end cannot be on the same line.
An example:
<database>
host = muli
user = moare
dbname = modb
dbpass = D4r_9Iu
</database>
Blocks can also be nested. Here is a more complicated example:
user = hans
server = mc200
db = maxis
passwd = D3rf$
<jonas>
user = tom
db = unknown
host = mila
<tablestructure>
index int(100000)
name char(100)
prename char(100)
city char(100)
status int(10)
allowed moses
allowed ingram
allowed joice
</tablestructure>
</jonas>
The hash which the method getall returns look like that:
print Data::Dumper(\%hash);
$VAR1 = {
'passwd' => 'D3rf$',
'jonas' => {
'tablestructure' => {
'prename' => 'char(100)',
'index' => 'int(100000)',
'city' => 'char(100)',
'name' => 'char(100)',
'status' => 'int(10)',
'allowed' => [
'moses',
'ingram',
'joice',
]
},
'host' => 'mila',
'db' => 'unknown',
'user' => 'tom'
},
'db' => 'maxis',
'server' => 'mc200',
'user' => 'hans'
};
If you have turned on -LowerCaseNames (see new()) then blocks as in the
following example:
<Dir>
<AttriBUTES>
Owner root
</attributes>
</dir>
would produce the following hash structure:
$VAR1 = {
'dir' => {
'attributes' => {
'owner' => "root",
}
}
};
As you can see, the keys inside the config hash are normalized.
Please note, that the above config block would result in a valid hash
structure, even if -LowerCaseNames is not set! This is because
Config::General does not use the block names to check if a block ends,
instead it uses an internal state counter, which indicates a block end.
If the module cannot find an end-block statement, then this block will
be ignored.
NAMED BLOCKS
If you need multiple blocks of the same name, then you have to name
every block. This works much like Apache config. If the module finds a
named block, it will create a hashref with the left part of the named
block as the key containing one or more hashrefs with the right part of
the block as key containing everything inside the block(which may again
be nested!). As examples says more than words:
# given the following sample
<Directory /usr/frisco>
Limit Deny
Options ExecCgi Index
</Directory>
<Directory /usr/frik>
Limit DenyAll
Options None
</Directory>
# you will get:
$VAR1 = {
'Directory' => {
'/usr/frik' => {
'Options' => 'None',
'Limit' => 'DenyAll'
},
'/usr/frisco' => {
'Options' => 'ExecCgi Index',
'Limit' => 'Deny'
}
}
};
You cannot have more than one named block with the same name because it
will be stored in a hashref and therefore be overwritten if a block
occurs once more.
WHITESPACE IN BLOCKS
The normal behavior of Config::General is to look for whitespace in
block names to decide if it's a named block or just a simple block.
Sometimes you may need blocknames which have whitespace in their names.
With named blocks this is no problem, as the module only looks for the
first whitespace:
<person hugo gera>
</person>
would be parsed to:
$VAR1 = {
'person' => {
'hugo gera' => {
},
}
};
The problem occurs, if you want to have a simple block containing
whitespace:
<hugo gera>
</hugo gera>
This would be parsed as a named block, which is not what you wanted. In
this very case you may use quotation marks to indicate that it is not a
named block:
<"hugo gera">
</"hugo gera">
The save() method of the module inserts automatically quotation marks
in such cases.
EXPLICIT EMPTY BLOCKS
Beside the notation of blocks mentioned above it is possible to use
explicit empty blocks.
Normally you would write this in your config to define an empty block:
<driver Apache>
</driver>
To save writing you can also write:
<driver Apache/>
which is the very same as above. This works for normal blocks and for
named blocks.
IDENTICAL OPTIONS (ARRAYS)
You may have more than one line of the same option with different
values. Example:
log log1
log log2
log log2
You will get a scalar if the option occurred only once or an array if
it occurred more than once. If you expect multiple identical options,
then you may need to check if an option occurred more than once:
$allowed = $hash{jonas}->{tablestructure}->{allowed};
if (ref($allowed) eq "ARRAY") {
@ALLOWED = @{$allowed};
else {
@ALLOWED = ($allowed);
}
}
The same applies to blocks and named blocks too (they are described in
more detail below). For example, if you have the following config:
<dir blah>
user max
</dir>
<dir blah>
user hannes
</dir>
then you would end up with a data structure like this:
$VAR1 = {
'dir' => {
'blah' => [
{
'user' => 'max'
},
{
'user' => 'hannes'
}
]
}
};
As you can see, the two identical blocks are stored in a hash which
contains an array(-reference) of hashes.
Under some rare conditions you might not want this behavior with blocks
(and named blocks too). If you want to get one single hash with the
contents of both identical blocks, then you need to turn the new()
parameter -MergeDuplicateBlocks on (see above). The parsed structure of
the example above would then look like this:
$VAR1 = {
'dir' => {
'blah' => {
'user' => [
'max',
'hannes'
]
}
}
};
As you can see, there is only one hash "dir->{blah}" containing
multiple "user" entries. As you can also see, turning on
-MergeDuplicateBlocks does not affect scalar options (i.e. "option =
value"). In fact you can tune merging of duplicate blocks and options
independent from each other.
If you don't want to allow more than one identical options, you may
turn it off by setting the flag AllowMultiOptions in the new() method
to "no". If turned off, Config::General will complain about multiple
occurring options with identical names!
FORCE SINGLE VALUE ARRAYS
You may also force a single config line to get parsed into an array by
turning on the option -ForceArray and by surrounding the value of the
config entry by []. Example:
hostlist = [ foo.bar ]
Will be a singlevalue array entry if the option is turned on. If you
want it to remain to be an array you have to turn on -ForceArray during
save too.
LONG LINES
If you have a config value, which is too long and would take more than
one line, you can break it into multiple lines by using the backslash
character at the end of the line. The Config::General module will
concatenate those lines to one single-value.
Example:
command = cat /var/log/secure/tripwire | \
mail C<-s> "report from tripwire" \
honey@myotherhost.nl
command will become: "cat /var/log/secure/tripwire | mail "-s" 'report
from twire' honey@myotherhost.nl"
HERE DOCUMENTS
You can also define a config value as a so called "here-document". You
must tell the module an identifier which indicates the end of a here
document. An identifier must follow a "<<".
Example:
message <<EOF
we want to
remove the
homedir of
root.
EOF
Everything between the two "EOF" strings will be in the option message.
There is a special feature which allows you to use indentation with
here documents. You can have any amount of whitespace or tabulators in
front of the end identifier. If the module finds spaces or tabs then it
will remove exactly those amount of spaces from every line inside the
here-document.
Example:
message <<EOF
we want to
remove the
homedir of
root.
EOF
After parsing, message will become:
we want to
remove the
homedir of
root.
because there were the string " " in front of EOF, which were cut
from every line inside the here-document.
INCLUDES
You can include an external file at any position in your config file
using the following statement in your config file:
<<include externalconfig.rc>>
If you turned on -UseApacheInclude (see new()), then you can also use
the following statement to include an external file:
include externalconfig.rc
This file will be inserted at the position where it was found as if the
contents of this file were directly at this position.
You can also recursively include files, so an included file may include
another one and so on. Beware that you do not recursively load the
same file, you will end with an error message like "too many open files
in system!".
By default included files with a relative pathname will be opened from
within the current working directory. Under some circumstances it maybe
possible to open included files from the directory, where the
configfile resides. You need to turn on the option -IncludeRelative
(see new()) if you want that. An example:
my $conf = Config::General(
-ConfigFile => "/etc/crypt.d/server.cfg"
-IncludeRelative => 1
);
/etc/crypt.d/server.cfg:
<<include acl.cfg>>
In this example Config::General will try to include acl.cfg from
/etc/crypt.d:
/etc/crypt.d/acl.cfg
The default behavior (if -IncludeRelative is not set!) will be to open
just acl.cfg, wherever it is, i.e. if you did a
chdir("/usr/local/etc"), then Config::General will include:
/usr/local/etc/acl.cfg
Include statements can be case insensitive (added in version 1.25).
Include statements will be ignored within C-Comments and here-
documents.
By default, a config file will only be included the first time it is
referenced. If you wish to include a file in multiple places, set
/-IncludeAgain to true. But be warned: this may lead to infinite loops,
so make sure, you're not including the same file from within itself!
Example:
# main.cfg
<object billy>
class=Some::Class
<printers>
include printers.cfg
</printers>
# ...
</object>
<object bob>
class=Another::Class
<printers>
include printers.cfg
</printers>
# ...
</object>
Now "printers.cfg" will be include in both the "billy" and "bob"
objects.
You will have to be careful to not recursively include a file.
Behaviour in this case is undefined.
COMMENTS
A comment starts with the number sign #, there can be any number of
spaces and/or tab stops in front of the #.
A comment can also occur after a config statement. Example:
username = max # this is the comment
If you want to comment out a large block you can use C-style comments.
A /* signals the begin of a comment block and the */ signals the end of
the comment block. Example:
user = max # valid option
db = tothemax
/*
user = andors
db = toand
*/
In this example the second options of user and db will be ignored.
Please beware of the fact, if the Module finds a /* string which is the
start of a comment block, but no matching end block, it will ignore the
whole rest of the config file!
NOTE: If you require the # character (number sign) to remain in the
option value, then you can use a backslash in front of it, to escape
it. Example:
bgcolor = \#ffffcc
In this example the value of $config{bgcolor} will be "#ffffcc",
Config::General will not treat the number sign as the begin of a
comment because of the leading backslash.
Inside here-documents escaping of number signs is NOT required!
PARSER PLUGINS
You can alter the behavior of the parser by supplying closures which
will be called on certain hooks during config file processing and
parsing.
The general aproach works like this:
sub ck {
my($file, $base) = @_;
print "_open() tries $file ... ";
if ($file =~ /blah/) {
print "ignored\n";
return (0);
} else {
print "allowed\n";
return (1, @_);
}
}
my %c = ParseConfig(
-IncludeGlob => 1,
-UseApacheInclude => 1,
-ConfigFile => shift,
-Plug => { pre_open => *ck }
);
Output:
_open() tries cfg ... allowed
_open() tries x/*.conf ... allowed
_open() tries x/1.conf ... allowed
_open() tries x/2.conf ... allowed
_open() tries x/blah.conf ... ignored
As you can see, we wrote a little sub which takes a filename and a base
directory as parameters. We tell Config::General via the Plug parameter
of new() to call this sub everytime before it attempts to open a file.
General processing continues as usual if the first value of the
returned array is true. The second value of that array depends on the
kind of hook being called.
The following hooks are available so far:
pre_open
Takes two parameters: filename and basedirectory.
Has to return an array consisting of 3 values:
- 1 or 0 (continue processing or not)
- filename
- base directory
pre_read
Takes two parameters: the filehandle of the file to be read and an
array containing the raw contents of said file.
This hook will be applied in _read(). File contents are already
available at this stage, comments will be removed, here-docs
normalized and the like. This hook gets the unaltered, original
contents.
Has to return an array of 3 values:
- 1 or 0 (continue processing or not)
- the filehandle
- an array of strings
You can use this hook to apply your own normalizations or whatever.
Be careful when returning the abort value (1st value of returned
array 0), since in this case nothing else would be done on the
contents. If it still contains comments or something, they will be
parsed as legal config options.
post_read
Takes one parameter: a reference to an array containing the
prepared config lines (after being processed by _read()).
This hook will be applied in _read() when everything else has been
done.
Has to return an array of 2 values:
- 1 or 0 (continue processing or not) [Ignored for post hooks]
- a reference to an array containing the config lines
pre_parse_value
Takes 2 parameters: an option name and its value.
This hook will be applied in _parse_value() before any processing.
Has to return an array of 3 values:
- 1 or 0 (continue processing or not)
- option name
- value of the option
post_parse_value
Almost identical to pre_parse_value, but will be applied after
_parse_value() is finished and all usual processing and
normalization is done.
Not implemented yet: hooks for variable interpolation and block
parsing.
OBJECT ORIENTED INTERFACE
There is a way to access a parsed config the OO-way. Use the module
Config::General::Extended, which is supplied with the Config::General
distribution.
VARIABLE INTERPOLATION
You can use variables inside your config files if you like. To do that
you have to use the module Config::General::Interpolated, which is
supplied with the Config::General distribution.
EXPORTED FUNCTIONS
Config::General exports some functions too, which makes it somewhat
easier to use it, if you like this.
How to import the functions:
use Config::General qw(ParseConfig SaveConfig SaveConfigString);
ParseConfig()
This function takes exactly all those parameters, which are allowed
to the new() method of the standard interface.
Example:
use Config::General qw(ParseConfig);
my %config = ParseConfig(-ConfigFile => "rcfile", -AutoTrue => 1);
SaveConfig()
This function requires two arguments, a filename and a reference to
a hash structure.
Example:
use Config::General qw(SaveConfig);
..
SaveConfig("rcfile", \%some_hash);
SaveConfigString()
This function requires a reference to a config hash as parameter.
It generates a configuration based on this hash as the object-
interface method save_string() does.
Example:
use Config::General qw(ParseConfig SaveConfigString);
my %config = ParseConfig(-ConfigFile => "rcfile");
.. # change %config something
my $content = SaveConfigString(\%config);
CONFIGURATION AND ENVIRONMENT
No environment variables will be used.
SEE ALSO
I recommend you to read the following documents, which are supplied
with Perl:
perlreftut Perl references short introduction
perlref Perl references, the rest of the story
perldsc Perl data structures intro
perllol Perl data structures: arrays of arrays
Config::General::Extended Object oriented interface to parsed configs
Config::General::Interpolated Allows one to use variables inside config files
LICENSE AND COPYRIGHT
Copyright (c) 2000-2022 Thomas Linden
This library is free software; you can redistribute it and/or modify it
under the same terms of the Artistic License 2.0.
BUGS AND LIMITATIONS
See rt.cpan.org for current bugs, if any.
INCOMPATIBILITIES
None known.
DIAGNOSTICS
To debug Config::General use the Perl debugger, see perldebug.
DEPENDENCIES
Config::General depends on the modules FileHandle,
File::Spec::Functions, File::Glob, which all are shipped with Perl.
AUTHOR
Thomas Linden <tlinden |AT| cpan.org>
VERSION
2.65
perl v5.34.0 2022-10-13 General(3pm)
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