phpman > perldoc > Config::Simple(3pm)

NAME
    Config::Simple - simple configuration file class

SYNOPSIS
      use Config::Simple;

      # --- Simple usage. Loads the config. file into a hash:
      Config::Simple->import_from('app.ini', \%Config);


      # --- OO interface:
      $cfg = new Config::Simple('app.ini');

      # accessing values:
      $user = $cfg->param('User');

      # getting the values as a hash:
      %Config = $cfg->vars();

      # updating value with a string
      $cfg->param('User', 'sherzodR');

      # updating a value with an array:
      $cfg->param('Users', ['sherzodR', 'geek', 'merlyn']);

      # adding a new block to an ini-file:
      $cfg->param(-block=>'last-access', -values=>{'time'=>time()});

      # accessing a block of an ini-file;
      $mysql = $cfg->param(-block=>'mysql');

      # saving the changes back to file:
      $cfg->save();


      # --- tie() interface
      tie %Config, "Config::Simple", 'app.ini';

ABSTRACT
    Reading and writing configuration files is one of the most frequent tasks of any software
    design. Config::Simple is the library that helps you with it.

    Config::Simple is a class representing configuration file object. It supports several
    configuration file syntax and tries to identify the file syntax automatically. Library supports
    parsing, updating and creating configuration files.

ABOUT CONFIGURATION FILES
    Keeping configurable variables in your program source code is ugly, really. And for people
    without much of a programming experience, configuring your programs is like performing black
    magic. Besides, if you need to access these values from within multiple files, want your
    programs to be able to update configuration files or want to provide a friendlier user interface
    for your configuration files, you just have to store them in an external file. That's where
    Config::Simple comes into play, making it very easy to read and write configuration files.

    If you have never used configuration files before, here is a brief overview of various syntax to
    choose from. Otherwise you can jump to "PROGRAMMING STYLE".

  SIMPLE CONFIGURATION FILE
    Simple syntax is what you need for most of your projects. These are, as the name asserts, the
    simplest. File consists of key/value pairs, delimited by nothing but white space. Keys
    (variables) should be strictly alpha-numeric with possible dashes (-). Values can hold any
    arbitrary text. Here is an example of such a configuration file:

      Alias     /exec
      TempFile  /usr/tmp

    Comments start with a pound ('#') sign and cannot share the same line with other configuration
    data.

  HTTP-LIKE SYNTAX
    This format of separating key/value pairs is used by HTTP messages. Each key/value is separated
    by semi-colon (:). Keys are alphanumeric strings with possible '-'. Values can be any arbitrary
    text:

    Example:

      Alias: /exec
      TempFile: /usr/tmp

    It is OK to have spaces around ':'. Comments start with '#' and cannot share the same line with
    other configuration data.

  INI-FILE
    These configuration files are more native to Win32 systems. Data is organized in blocks. Each
    key/value pair is delimited with an equal (=) sign. Blocks are declared on their own lines
    enclosed in '[' and ']':

      [BLOCK1]
      KEY1=VALUE1
      KEY2=VALUE2


      [BLOCK2]
      KEY1=VALUE1
      KEY2=VALUE2

    Your Winamp 2.x play list is an example of such a configuration file.

    This is the perfect choice if you need to organize your configuration file into categories:

      [site]
      url="http://www.handalak.com"
      title="Web site of a \"Geek\""
      author=sherzodr

      [mysql]
      dsn="dbi:mysql:db_name;host=handalak.com"
      user=sherzodr
      password=marley01

  SIMPLIFIED INI-FILE
    These files are pretty much similar to traditional ini-files, except they don't have any block
    declarations. This style is handy if you do not want any categorization in your configuration
    file, but still want to use '=' delimited key/value pairs. While working with such files,
    Config::Simple assigns them to a default block, called 'default' by default :-).

      url = "http://www.handalak.com"

    Comments can begin with either pound ('#') or semi-colon (';'). Each comment should reside on
    its own line

PROGRAMMING STYLE
    Most of the programs simply need to be able to read settings from a configuration file and
    assign them to a hash. If that's all you need, you can simply use its import_from() - class
    method with the name of the configuration file and a reference to an existing (possibly empty)
    hash:

      Config::Simple->import_from('myconf.cfg', \%Config);

    Now your hash %Config holds all the configuration file's key/value pairs. Keys of a hash are
    variable names inside your configuration file, and values are their respective values. If
    "myconf.cfg" was a traditional ini-file, keys of the hash consist of block name and variable
    delimited with a dot, such as "block.var".

    If that's all you need, you can stop right here. Otherwise, read on. There is much more
    Config::Simple offers.

  READING THE CONFIGURATION FILE
    To be able to use more features of the library, you will need to use its object interface:

      $cfg = new Config::Simple('app.cfg');

    The above line reads and parses the configuration file accordingly. It tries to guess which
    syntax is used by passing the file to guess_syntax() method. Alternatively, you can create an
    empty object, and only then read the configuration file in:

      $cfg = new Config::Simple();
      $cfg->read('app.cfg');

    As in the first example, read() also calls guess_syntax() method on the file.

    If, for any reason, it fails to guess the syntax correctly (which is less likely), you can try
    to debug by using its guess_syntax() method. It expects file handle for a configuration file and
    returns the name of a syntax. Return value is one of "ini", "simple" or "http".

      open(FH, "app.cfg");
      printf("This file uses '%s' syntax\n", $cfg->guess_syntax(\*FH));

  ACCESSING VALUES
    After you read the configuration file in successfully, you can use param() method to access the
    configuration values. For example:

      $user = $cfg->param("User");

    will return the value of "User" from either simple configuration file, or http-styled
    configuration as well as simplified ini-files. To access the value from a traditional ini-file,
    consider the following syntax:

      $user = $cfg->param("mysql.user");

    The above returns the value of "user" from within "[mysql]" block. Notice the use of dot "." to
    delimit block and key names.

    Config::Simple also supports vars() method, which, depending on the context used, returns all
    the values either as hashref or hash:

      my %Config = $cfg->vars();
      print "Username: $Config{User}";

      # If it was a traditional ini-file:
      print "Username: $Config{'mysql.user'}";

    If you call vars() in scalar context, you will end up with a reference to a hash:

      my $Config = $cfg->vars();
      print "Username: $Config->{User}";

    If you know what you're doing, you can also have an option of importing all the names from the
    configuration file into your current name space as global variables. All the block/key names
    will be uppercased and will be converted to Perl's valid variable names; that is, all the dots
    (block-key separator) and other '\W' characters will be substituted with underscore '_':

      $cfg = new Config::Simple('app.cfg');
      $cfg->import_names();

      # or, with a single line:
      Config::Simple->new('app.cfg')->import_names();

      print STDERR "Debugging mode is on" if $DEBUG_MODE;

    In the above example, if there was a variable 'mode' under '[debug]' block, it will be now
    accessible via $DEBUG_MODE, as opposed to $cfg->param('debug.mode');

    "import_names()" by default imports the values to its caller's name space. Optionally, you can
    specify where to import the values by passing the name of the name space as the first argument.
    It also prevents potential name collisions:

      Config::Simple->new('app.cfg')->import_names('CFG');
      print STDERR "Debugging mode is on" if $CFG::DEBUG_MODE;

    If all you want is to import values from a configuration file, the above syntax may still seem
    longer than necessary. That's why Config::Simple supports import_from() - class method, which is
    called with the name of the configuration file. It will call import_names() for you:

      Config::Simple->import_from('app.cfg');

    The above line imports all the variables into the caller's name space. It's similar to calling
    import_names() on an object. If you pass a string as the second argument, it will treat it as
    the alternative name space to import the names into. As we already showed in the very first
    example, you can also pass a reference to an existing hash as the second argument. In this case,
    that hash will be modified with the values of the configuration file.

      # import into $CFG name space:
      Config::Simple->import_from('app.cfg', 'CFG');

      # import into %Config hash:
      Config::Simple->import_from('app.cfg', \%Config);

    The above line imports all the values to 'CFG' name space. import_from() returns underlying
    Config::Simple object (which you may not even need anymore):

      $cfg = Config::Simple->import_from('app.cfg', \my %Config);
      $cfg->write('app.cfg.bak');

  UPDATING THE VALUES
    Configuration values, once read into Config::Simple, can be updated from within your program by
    using the same param() method used for accessing them. For example:

      $cfg->param("User", "sherzodR");

    The above line changes the value of "User" to "sherzodR". Similar syntax is applicable for
    ini-files as well:

      $cfg->param("mysql.user", "sherzodR");

    If the key you're trying to update does not exist, it will be created. For example, to add a new
    "[session]" block to your ini-file, assuming this block doesn't already exist:

      $cfg->param("session.life", "+1M");

    You can also delete values calling delete() method with the name of the variable:

      $cfg->delete('mysql.user'); # deletes 'user' under [mysql] block

  SAVING/WRITING CONFIGURATION FILES
    The above updates to the configuration values are in-memory operations. They do not reflect in
    the file itself. To modify the files accordingly, you need to call either "write()" or "save()"
    methods on the object:

      $cfg->write();

    The above line writes the modifications to the configuration file. Alternatively, you can pass a
    name to either write() or save() to indicate the name of the file to create instead of modifying
    existing configuration file:

      $cfg->write("app.cfg.bak");

    If you want the changes saved at all times, you can turn "autosave" mode on by passing true
    value to $cfg->autosave(). It will make sure before your program is terminated, all the
    configuration values are written back to its file:

      $cfg = new Config::Simple('aff.cfg');
      $cfg->autosave(1);

  CREATING CONFIGURATION FILES
    Occasionally, your programs may want to create their own configuration files on the fly,
    possibly from a user input. To create a configuration file from scratch using Config::Simple,
    simply create an empty configuration file object and define your syntax. You can do it by either
    passing "syntax" option to new(), or by calling syntax() method. Then play with param() method
    as you normally would. When you're done, call write() method with the name of the configuration
    file:

      $cfg = new Config::Simple(syntax=>'ini');
      # or you could also do:
      # $cfg->autosave('ini')

      $cfg->param("mysql.dsn", "DBI:mysql:db;host=handalak.com");
      $cfg->param("mysql.user", "sherzodr");
      $cfg->param("mysql.pass", 'marley01');
      $cfg->param("site.title", 'sherzodR "The Geek"');
      $cfg->write("new.cfg");

    This creates a file "new.cfg" with the following content:

      ; Config::Simple 4.43
      ; Sat Mar  8 00:32:49 2003

      [site]
      title=sherzodR "The Geek"

      [mysql]
      pass=marley01
      dsn=DBI:mysql:db;host=handalak.com
      user=sherzodr

    Neat, huh? Supported syntax keywords are "ini", "simple" or "http". Currently there is no
    support for creating simplified ini-files.

  MULTIPLE VALUES
    Ever wanted to define array of values in your single configuration variable? I have! That's why
    Config::Simple supports this fancy feature as well. Simply separate your values with a comma:

      Files hp.cgi, template.html, styles.css

    Now param() method returns an array of values:

      @files = $cfg->param("Files");
      unlink $_ for @files;

    If you want a comma as part of a value, enclose the value(s) in double quotes:

      CVSFiles "hp.cgi,v", "template.html,v", "styles.css,v"

    In case you want either of the values to hold literal quote ("), you can escape it with a
    backlash:

      SiteTitle "sherzod \"The Geek\""

  TIE INTERFACE
    If OO style intimidates you, and "import_from()" is too simple for you, Config::Simple also
    supports tie() interface. This interface allows you to tie() an ordinary Perl hash to the
    configuration file. From that point on, you can use the variable as an ordinary Perl hash.

      tie %Config, "Config::Simple", 'app.cfg';

      # Using %Config as an ordinary hash
      print "Username is '$Config{User}'\n";
      $Config{User} = 'sherzodR';

    The difference between "import_from($file, \%Hash)" is, all the changes you make to the hash
    after tie()ing it, will also reflect in the configuration file object. If autosave() was turned
    on, they will also be written back to file:

      tie %Config, "Config::Simple", "app.cfg";
      tied(%Config)->autosave(1);

    To access the method provided in OO syntax, you need to get underlying Config::Simple object.
    You can do so with tied() function:

      tied(%Config)->write();

    WARNING: tie interface is experimental and not well tested yet. Let me know if you encounter a
    problem.

MISCELLANEOUS
  CASE SENSITIVITY
    By default, configuration file keys and values are case sensitive. Which means,
    $cfg->param("User") and $cfg->param("user") are referring to two different values. But it is
    possible to force Config::Simple to ignore cases all together by enabling "-lc" switch while
    loading the library:

      use Config::Simple ('-lc');

    WARNING: If you call write() or save(), while working on "-lc" mode, all the case information of
    the original file will be lost. So use it if you know what you're doing.

  USING QUOTES
    Some people suggest if values consist of none alpha-numeric strings, they should be enclosed in
    double quotes. Well, says them! Although Config::Simple supports parsing such configuration
    files already, it doesn't follow this rule while writing them. If you really need it to generate
    such compatible configuration files, "-strict" switch is what you need:

      use Config::Simple '-strict';

    Now, when you write the configuration data back to files, if values hold any none alpha-numeric
    strings, they will be quoted accordingly. All the double quotes that are part of the value will
    be escaped with a backslash.

  EXCEPTION HANDLING
    Config::Simple doesn't believe in dying that easily (unless you insult it using wrong syntax).
    It leaves the decision to the programmer implementing the library. You can use its error() -
    class method to access underlying error message. Methods that require you to check for their
    return values are read() and write(). If you pass filename to new(), you will need to check its
    return value as well. They return any true value indicating success, undef otherwise:

      # following new() always returns true:
      $cfg = new Config::Simple();

      # read() can fail:
      $cfg->read('app.cfg') or die $cfg->error();

      # following new() can fail:
      $cfg = new Config::Simple('app.cfg') or die Config::Simple->error();

      # import_from() calls read(), so it can fail:
      Config::Simple->import_from('app.cfg', \%Config) or die Config::Simple->error();

      # write() may fail:
      $cfg->write() or die $cfg->error();

      # tie() may fail, since it calls new() with a filename
      tie %Config, "Config::Simple", 'app.cfg' or die Config::Simple->error();

METHODS
    new()
        - constructor. Optionally accepts several arguments. Returns Config::Simple object.
        Supported arguments are filename, syntax, autosave. If there is a single argument, will be
        treated as the name of the configuration file.

    autosave([$bool])
        - turns 'autosave' mode on if passed true argument. Returns current autosave mode if used
        without arguments. In 'autosave' mode Config::Simple writes all the changes back to its file
        without you having to call write() or save()

    read()
        - accepts name of the configuration file to parse. Before that, it tries to guess the syntax
        of the file by calling guess_syntax() method. Then calls either of parse_ini_file(),
        parse_cfg_file() or parse_http_file() accordingly. If the name of the file is provided to
        the constructor - new(), there is no need to call read().

    param([$name], [$value])
        - used for accessing and updating configuration variables. If used with no arguments returns
        all the available names from the configuration file.

    delete($name)
        - deletes a variable from a configuration file. $name has the same meaning and syntax as it
        does in param($name)

    clear()
        - clears all the data from the object. Calling save() or turning autosave() on results in an
        empty configuration file as well.

    vars()
        - depending on the context used, returns all the values available in the configuration file
        either as a hash or a reference to a hash

    import_names([$NS])
        - imports all the names from the configuration file to the caller's name space. Optional
        argument, if passed, will be treated as the name space variables to be imported into. All
        the names will be uppercased. Non-alphanumeric strings in the values will be underscored

    import_from($file, \%hash | $NS)
        - class method. If the second argument is a reference to an existing hash, it will load all
        the configuration contents into that hash. If the second argument is a string, it will be
        treated as the name space variables should be imported into, just like import_names() does.

    get_block($name)
        is mostly used for accessing blocks in ini-styled configuration files. Returns a hashref of
        all the key/value pairs of a given block. Also supported by param() method with the help of
        "-block" option:

          $hash = $cfg->get_block('Project');
          # is the same as saying:
          $hash = $cfg->param(-block=>'Project');

    set_block($name, $values)
        used in assigning contents to a block in ini-styled configuration files. $name should be the
        name of a [block], and $values is assumed to be a hashref mapping key/value pairs. Also
        supported by param() method with the help of "-block" and "-value" (or "-values") options:

          $cfg->set_block('Project', {Count=>3, 'Multiple Column' => 20});
          # is the same as:
          $cfg->param(-block=>'Project', -value=>{Count=>3, 'Multiple Column' => 20});

        Warning: all the contents of a block, if previously existed will be wiped out. If you want
        to set specific key/value pairs, use explicit method:

          $cfg->param('Project.Count', 3);

    as_string()
        - returns the configuration file as a chunk of text. It is the same text used by write() and
        save() to store the new configuration file back to file.

    write()
        - writes the configuration file into disk. Argument, if passed, will be treated as the name
        of the file configuration variables should be saved in.

    save()
        - same as write().

    dump()
        - for debugging only. Dumps the whole Config::Simple object using Data::Dumper. Argument, if
        passed, will be treated as the name of the file object should be dumped in. The second
        argument specifies amount of indentation as documented in Data::Dumper manual. Default
        indent size is 2.

    error()
        - returns the last error message from read/write or import_* operations.

TODO
    *   Support for lines with continuation character, '\'. Currently its support is restricted and
        quite possibly buggy.

    *   Retaining comments while writing the configuration files back and/or methods for
        manipulating comments. Everyone loves comments!

    *   Retain the order of the blocks and other variables in the configuration files.

BUGS
    Submit bugs and possibly patches to Sherzod B. Ruzmetov <sherzodr AT cpan.org>.

CREDITS
    Michael Caldwell (mjc AT mjcnet.com)
        whitespace support, "-lc" switch and for various bug fixes

    Scott Weinstein (Scott.Weinstein AT lazard.com)
        bug fix in TIEHASH

    Ruslan U. Zakirov <cubic AT wr.ru>
        default name space suggestion and patch

    Hirosi Taguti
        import_names() and import_from() idea.

    Vitaly Kushneriuk
        for bug fixes and suggestions

COPYRIGHT
      Copyright (C) 2002-2003 Sherzod B. Ruzmetov.

      This software is free library. You can modify and/or distribute it
      under the same terms as Perl itself

AUTHOR
      Sherzod B. Ruzmetov E<lt>sherzodr AT cpan.orgE<gt>
      URI: http://author.handalak.com

SEE ALSO
    Config::General, Config::Simple, Config::Tiny