General(3)

NAME
Config::General - Generic Config Module

SYNOPSIS
 #
 # the OOP way
 use Config::General;
 $conf = new Config::General("rcfile");
 my %config = $conf->getall;
 #
 # the procedural way
 use Config::General;
 my %config = ParseConfig("rcfile");

DESCRIPTION
This module opens a config file and parses it's 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 it's 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.

METHODS
Possible ways to call new():

 $conf = new Config::General("rcfile");
 $conf = new Config::General(\%somehash);
 $conf = new Config::General( %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:
    A filename or a filehandle, i.e.:

     -file => "rcfile" or -file => \$FileHandle
    A hash reference, which will be used as the config, i.e.:

     -hash => \%somehash
    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
    If the value is "no", then multiple identical options are disallowed. The default is "yes". i.e.:

     -AllowMultiOptions => "no"
    see IDENTICAL OPTIONS for details. 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. If set to a true value, the parser will consider "include ..." as valid include statement (just like the well known apache include statement). 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 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. 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 "oN" will result in 1. 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 = new Config::General(
             -file => "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 occurences of thos variables will be handled this way, there is no way to distinguish between variables in different scopes. That means, that 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.
This method only exists for compatibility reasons and is deprecated. Now you should set the parameter to the new() method -AllowMultiOptions to "no".

see METHODS. Returns a hash structure which represents the whole config. Deprectated. Use save_file() instead! Writes the config hash back to the harddisk. 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 occurence 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");
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 begining with # and empty lines will be ignored. (see section COMMENTS!) Spaces at the begining 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 use apostrophs ". An optionline starts with it's name followed by a value. An equalsign 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>. 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 blocknames 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.

IDENTICAL OPTIONS
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 occured only once or an array if it occured more than once. If you expect multiple identical options, then you may need to check if an option occured 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',
                                  'user' => '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").

If you don't want to allow more than one identical options, you may turn it off by setting the flag AllowMutliOptions in the new() method to "no". If turned off, Config::General will complain about multiple occuring options whit identical names!

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 `-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 identicates 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 whitespaces 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 cutted from every line inside the here-document.

INCLUDES
You can include an external file at any posision 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 recurively 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 errormessage 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(
                             -file => "/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, whereever 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.

COMMENTS
A comment starts with the number sign #, there can be any number of spaces and/or tabstops 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 backlsash 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!

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 configfiles 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. This function takes exactly all those parameters, which are allowed to the new() method of the standard interface.

Example:

 use Config::General;
 my %config = ParseConfig(-file => "rcfile", -AutoTrue => 1);
This function requires two arguments, a filename and a reference to a hash structure.

Example:

 use Config::General;
 ..
 SaveConfig("rcfile", \%some_hash);
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;
 my %config = ParseConfig(-file => "rcfile");
 .. # change %config something
 my $content = SaveConfigString(\%config);

SEE ALSO
I recommend you to read the following documentations, 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 to use variables inside config files

COPYRIGHT
Copyright (c) 2000-2002 Thomas Linden

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

BUGS
none known yet.

AUTHOR
Thomas Linden <tom@daemon.de>

VERSION
1.29