1Simple(3) User Contributed Perl Documentation Simple(3)
2
6 Config::Simple - simple configuration file class
7
9 use Config::Simple;
10 # --- Simple usage. Loads the config. file into a hash:
12 Config::Simple->import_from('app.ini', \%Config);
13 # --- OO interface:
16 $cfg = new Config::Simple('app.ini');
17 # accessing values:
19 $user = $cfg->param('User');
20 # getting the values as a hash:
22 %Config = $cfg->vars();
23 # updating value with a string
25 $cfg->param('User', 'sherzodR');
26 # updating a value with an array:
28 $cfg->param('Users', ['sherzodR', 'geek', 'merlyn']);
29 # adding a new block to an ini-file:
31 $cfg->param(-block=>'last-access', -values=>{'time'=>time()});
32 # accessing a block of an ini-file;
34 $mysql = $cfg->param(-block=>'mysql');
35 # saving the changes back to file:
37 $cfg->save();
38 # --- tie() interface
41 tie %Config, "Config::Simple", 'app.ini';
42
44 Reading and writing configuration files is one of the most frequent
45 tasks of any software design. Config::Simple is the library that helps
46 you with it.
47 Config::Simple is a class representing configuration file object. It
49 supports several configuration file syntax and tries to identify the
50 file syntax automatically. Library supports parsing, updating and
51 creating configuration files.
52
54 Keeping configurable variables in your program source code is ugly,
55 really. And for people without much of a programming experience,
56 configuring your programs is like performing black magic. Besides, if
57 you need to access these values from within multiple files, want your
58 programs to be able to update configuration files or want to provide a
59 friendlier user interface for your configuration files, you just have
60 to store them in an external file. That's where Config::Simple comes
61 into play, making it very easy to read and write configuration files.
62 If you have never used configuration files before, here is a brief
64 overview of various syntax to choose from. Otherwise you can jump to
65 "PROGRAMMING STYLE".
66 SIMPLE CONFIGURATION FILE
68 Simple syntax is what you need for most of your projects. These are, as
69 the name asserts, the simplest. File consists of key/value pairs,
70 delimited by nothing but white space. Keys (variables) should be
71 strictly alpha-numeric with possible dashes (-). Values can hold any
72 arbitrary text. Here is an example of such a configuration file:
73 Alias /exec
75 TempFile /usr/tmp
76 Comments start with a pound ('#') sign and cannot share the same line
78 with other configuration data.
79 HTTP-LIKE SYNTAX
81 This format of separating key/value pairs is used by HTTP messages.
82 Each key/value is separated by semi-colon (:). Keys are alphanumeric
83 strings with possible '-'. Values can be any arbitrary text:
84 Example:
86 Alias: /exec
88 TempFile: /usr/tmp
89 It is OK to have spaces around ':'. Comments start with '#' and cannot
91 share the same line with other configuration data.
92 INI-FILE
94 These configuration files are more native to Win32 systems. Data is
95 organized in blocks. Each key/value pair is delimited with an equal (=)
96 sign. Blocks are declared on their own lines enclosed in '[' and ']':
97 [BLOCK1]
99 KEY1=VALUE1
100 KEY2=VALUE2
101 [BLOCK2]
104 KEY1=VALUE1
105 KEY2=VALUE2
106 Your Winamp 2.x play list is an example of such a configuration file.
108 This is the perfect choice if you need to organize your configuration
110 file into categories:
111 [site]
113 url="http://www.handalak.com"
114 title="Web site of a \"Geek\""
115 author=sherzodr
116 [mysql]
118 dsn="dbi:mysql:db_name;host=handalak.com"
119 user=sherzodr
120 password=marley01
121 SIMPLIFIED INI-FILE
123 These files are pretty much similar to traditional ini-files, except
124 they don't have any block declarations. This style is handy if you do
125 not want any categorization in your configuration file, but still want
126 to use '=' delimited key/value pairs. While working with such files,
127 Config::Simple assigns them to a default block, called 'default' by
128 default :-).
129 url = "http://www.handalak.com"
131 Comments can begin with either pound ('#') or semi-colon (';'). Each
133 comment should reside on its own line
134
136 Most of the programs simply need to be able to read settings from a
137 configuration file and assign them to a hash. If that's all you need,
138 you can simply use its import_from() - class method with the name of
139 the configuration file and a reference to an existing (possibly empty)
140 hash:
141 Config::Simple->import_from('myconf.cfg', \%Config);
143 Now your hash %Config holds all the configuration file's key/value
145 pairs. Keys of a hash are variable names inside your configuration
146 file, and values are their respective values. If "myconf.cfg" was a
147 traditional ini-file, keys of the hash consist of block name and
148 variable delimited with a dot, such as "block.var".
149 If that's all you need, you can stop right here. Otherwise, read on.
151 There is much more Config::Simple offers.
152 READING THE CONFIGURATION FILE
154 To be able to use more features of the library, you will need to use
155 its object interface:
156 $cfg = new Config::Simple('app.cfg');
158 The above line reads and parses the configuration file accordingly. It
160 tries to guess which syntax is used by passing the file to
161 guess_syntax() method. Alternatively, you can create an empty object,
162 and only then read the configuration file in:
163 $cfg = new Config::Simple();
165 $cfg->read('app.cfg');
166 As in the first example, read() also calls guess_syntax() method on the
168 file.
169 If, for any reason, it fails to guess the syntax correctly (which is
171 less likely), you can try to debug by using its guess_syntax() method.
172 It expects file handle for a configuration file and returns the name
173 of a syntax. Return value is one of "ini", "simple" or "http".
174 open(FH, "app.cfg");
176 printf("This file uses '%s' syntax\n", $cfg->guess_syntax(\*FH));
177 ACCESSING VALUES
179 After you read the configuration file in successfully, you can use
180 param() method to access the configuration values. For example:
181 $user = $cfg->param("User");
183 will return the value of "User" from either simple configuration file,
185 or http-styled configuration as well as simplified ini-files. To access
186 the value from a traditional ini-file, consider the following syntax:
187 $user = $cfg->param("mysql.user");
189 The above returns the value of "user" from within "[mysql]" block.
191 Notice the use of dot "." to delimit block and key names.
192 Config::Simple also supports vars() method, which, depending on the
194 context used, returns all the values either as hashref or hash:
195 my %Config = $cfg->vars();
197 print "Username: $Config{User}";
198 # If it was a traditional ini-file:
200 print "Username: $Config{'mysql.user'}";
201 If you call vars() in scalar context, you will end up with a reference
203 to a hash:
204 my $Config = $cfg->vars();
206 print "Username: $Config->{User}";
207 If you know what you're doing, you can also have an option of importing
209 all the names from the configuration file into your current name space
210 as global variables. All the block/key names will be uppercased and
211 will be converted to Perl's valid variable names; that is, all the dots
212 (block-key separator) and other '\W' characters will be substituted
213 with underscore '_':
214 $cfg = new Config::Simple('app.cfg');
216 $cfg->import_names();
217 # or, with a single line:
219 Config::Simple->new('app.cfg')->import_names();
220 print STDERR "Debugging mode is on" if $DEBUG_MODE;
222 In the above example, if there was a variable 'mode' under '[debug]'
224 block, it will be now accessible via $DEBUG_MODE, as opposed to
225 $cfg->param('debug.mode');
226 "import_names()" by default imports the values to its caller's name
228 space. Optionally, you can specify where to import the values by
229 passing the name of the name space as the first argument. It also
230 prevents potential name collisions:
231 Config::Simple->new('app.cfg')->import_names('CFG');
233 print STDERR "Debugging mode is on" if $CFG::DEBUG_MODE;
234 If all you want is to import values from a configuration file, the
236 above syntax may still seem longer than necessary. That's why
237 Config::Simple supports import_from() - class method, which is called
238 with the name of the configuration file. It will call import_names()
239 for you:
240 Config::Simple->import_from('app.cfg');
242 The above line imports all the variables into the caller's name space.
244 It's similar to calling import_names() on an object. If you pass a
245 string as the second argument, it will treat it as the alternative name
246 space to import the names into. As we already showed in the very first
247 example, you can also pass a reference to an existing hash as the
248 second argument. In this case, that hash will be modified with the
249 values of the configuration file.
250 # import into $CFG name space:
252 Config::Simple->import_from('app.cfg', 'CFG');
253 # import into %Config hash:
255 Config::Simple->import_from('app.cfg', \%Config);
256 The above line imports all the values to 'CFG' name space.
258 import_from() returns underlying Config::Simple object (which you may
259 not even need anymore):
260 $cfg = Config::Simple->import_from('app.cfg', \my %Config);
262 $cfg->write('app.cfg.bak');
263 UPDATING THE VALUES
265 Configuration values, once read into Config::Simple, can be updated
266 from within your program by using the same param() method used for
267 accessing them. For example:
268 $cfg->param("User", "sherzodR");
270 The above line changes the value of "User" to "sherzodR". Similar
272 syntax is applicable for ini-files as well:
273 $cfg->param("mysql.user", "sherzodR");
275 If the key you're trying to update does not exist, it will be created.
277 For example, to add a new "[session]" block to your ini-file, assuming
278 this block doesn't already exist:
279 $cfg->param("session.life", "+1M");
281 You can also delete values calling delete() method with the name of the
283 variable:
284 $cfg->delete('mysql.user'); # deletes 'user' under [mysql] block
286 SAVING/WRITING CONFIGURATION FILES
288 The above updates to the configuration values are in-memory operations.
289 They do not reflect in the file itself. To modify the files
290 accordingly, you need to call either "write()" or "save()" methods on
291 the object:
292 $cfg->write();
294 The above line writes the modifications to the configuration file.
296 Alternatively, you can pass a name to either write() or save() to
297 indicate the name of the file to create instead of modifying existing
298 configuration file:
299 $cfg->write("app.cfg.bak");
301 If you want the changes saved at all times, you can turn "autosave"
303 mode on by passing true value to $cfg->autosave(). It will make sure
304 before your program is terminated, all the configuration values are
305 written back to its file:
306 $cfg = new Config::Simple('aff.cfg');
308 $cfg->autosave(1);
309 CREATING CONFIGURATION FILES
311 Occasionally, your programs may want to create their own configuration
312 files on the fly, possibly from a user input. To create a configuration
313 file from scratch using Config::Simple, simply create an empty
314 configuration file object and define your syntax. You can do it by
315 either passing "syntax" option to new(), or by calling syntax() method.
316 Then play with param() method as you normally would. When you're done,
317 call write() method with the name of the configuration file:
318 $cfg = new Config::Simple(syntax=>'ini');
320 # or you could also do:
321 # $cfg->autosave('ini')
322 $cfg->param("mysql.dsn", "DBI:mysql:db;host=handalak.com");
324 $cfg->param("mysql.user", "sherzodr");
325 $cfg->param("mysql.pass", 'marley01');
326 $cfg->param("site.title", 'sherzodR "The Geek"');
327 $cfg->write("new.cfg");
328 This creates a file "new.cfg" with the following content:
330 ; Config::Simple 4.43
332 ; Sat Mar 8 00:32:49 2003
333 [site]
335 title=sherzodR "The Geek"
336 [mysql]
338 pass=marley01
339 dsn=DBI:mysql:db;host=handalak.com
340 user=sherzodr
341 Neat, huh? Supported syntax keywords are "ini", "simple" or "http".
343 Currently there is no support for creating simplified ini-files.
344 MULTIPLE VALUES
346 Ever wanted to define array of values in your single configuration
347 variable? I have! That's why Config::Simple supports this fancy
348 feature as well. Simply separate your values with a comma:
349 Files hp.cgi, template.html, styles.css
351 Now param() method returns an array of values:
353 @files = $cfg->param("Files");
355 unlink $_ for @files;
356 If you want a comma as part of a value, enclose the value(s) in double
358 quotes:
359 CVSFiles "hp.cgi,v", "template.html,v", "styles.css,v"
361 In case you want either of the values to hold literal quote ("), you
363 can escape it with a backlash:
364 SiteTitle "sherzod \"The Geek\""
366 TIE INTERFACE
368 If OO style intimidates you, and "import_from()" is too simple for you,
369 Config::Simple also supports tie() interface. This interface allows you
370 to tie() an ordinary Perl hash to the configuration file. From that
371 point on, you can use the variable as an ordinary Perl hash.
372 tie %Config, "Config::Simple", 'app.cfg';
374 # Using %Config as an ordinary hash
376 print "Username is '$Config{User}'\n";
377 $Config{User} = 'sherzodR';
378 The difference between "import_from($file, \%Hash)" is, all the changes
380 you make to the hash after tie()ing it, will also reflect in the
381 configuration file object. If autosave() was turned on, they will also
382 be written back to file:
383 tie %Config, "Config::Simple", "app.cfg";
385 tied(%Config)->autosave(1);
386 To access the method provided in OO syntax, you need to get underlying
388 Config::Simple object. You can do so with tied() function:
389 tied(%Config)->write();
391 WARNING: tie interface is experimental and not well tested yet. Let me
393 know if you encounter a problem.
394
396 CASE SENSITIVITY
397 By default, configuration file keys and values are case sensitive.
398 Which means, $cfg->param("User") and $cfg->param("user") are referring
399 to two different values. But it is possible to force Config::Simple to
400 ignore cases all together by enabling "-lc" switch while loading the
401 library:
402 use Config::Simple ('-lc');
404 WARNING: If you call write() or save(), while working on "-lc" mode,
406 all the case information of the original file will be lost. So use it
407 if you know what you're doing.
408 USING QUOTES
410 Some people suggest if values consist of none alpha-numeric strings,
411 they should be enclosed in double quotes. Well, says them! Although
412 Config::Simple supports parsing such configuration files already, it
413 doesn't follow this rule while writing them. If you really need it to
414 generate such compatible configuration files, "-strict" switch is what
415 you need:
416 use Config::Simple '-strict';
418 Now, when you write the configuration data back to files, if values
420 hold any none alpha-numeric strings, they will be quoted accordingly.
421 All the double quotes that are part of the value will be escaped with a
422 backslash.
423 EXCEPTION HANDLING
425 Config::Simple doesn't believe in dying that easily (unless you insult
426 it using wrong syntax). It leaves the decision to the programmer
427 implementing the library. You can use its error() - class method to
428 access underlying error message. Methods that require you to check for
429 their return values are read() and write(). If you pass filename to
430 new(), you will need to check its return value as well. They return any
431 true value indicating success, undef otherwise:
432 # following new() always returns true:
434 $cfg = new Config::Simple();
435 # read() can fail:
437 $cfg->read('app.cfg') or die $cfg->error();
438 # following new() can fail:
440 $cfg = new Config::Simple('app.cfg') or die Config::Simple->error();
441 # import_from() calls read(), so it can fail:
443 Config::Simple->import_from('app.cfg', \%Config) or die Config::Simple->error();
444 # write() may fail:
446 $cfg->write() or die $cfg->error();
447 # tie() may fail, since it calls new() with a filename
449 tie %Config, "Config::Simple", 'app.cfg' or die Config::Simple->error();
450
452 new()
453 - constructor. Optionally accepts several arguments. Returns
454 Config::Simple object. Supported arguments are filename, syntax,
455 autosave. If there is a single argument, will be treated as the
456 name of the configuration file.
457 autosave([$bool])
459 - turns 'autosave' mode on if passed true argument. Returns current
460 autosave mode if used without arguments. In 'autosave' mode
461 Config::Simple writes all the changes back to its file without you
462 having to call write() or save()
463 read()
465 - accepts name of the configuration file to parse. Before that, it
466 tries to guess the syntax of the file by calling guess_syntax()
467 method. Then calls either of parse_ini_file(), parse_cfg_file() or
468 parse_http_file() accordingly. If the name of the file is provided
469 to the constructor - new(), there is no need to call read().
470 param([$name], [$value])
472 - used for accessing and updating configuration variables. If used
473 with no arguments returns all the available names from the
474 configuration file.
475 delete($name)
477 - deletes a variable from a configuration file. $name has the same
478 meaning and syntax as it does in param($name)
479 clear()
481 - clears all the data from the object. Calling save() or turning
482 autosave() on results in an empty configuration file as well.
483 vars()
485 - depending on the context used, returns all the values available
486 in the configuration file either as a hash or a reference to a hash
487 import_names([$NS])
489 - imports all the names from the configuration file to the caller's
490 name space. Optional argument, if passed, will be treated as the
491 name space variables to be imported into. All the names will be
492 uppercased. Non-alphanumeric strings in the values will be
493 underscored
494 import_from($file, \%hash | $NS)
496 - class method. If the second argument is a reference to an
497 existing hash, it will load all the configuration contents into
498 that hash. If the second argument is a string, it will be treated
499 as the name space variables should be imported into, just like
500 import_names() does.
501 get_block($name)
503 is mostly used for accessing blocks in ini-styled configuration
504 files. Returns a hashref of all the key/value pairs of a given
505 block. Also supported by param() method with the help of "-block"
506 option:
507 $hash = $cfg->get_block('Project');
509 # is the same as saying:
510 $hash = $cfg->param(-block=>'Project');
511 set_block($name, $values)
513 used in assigning contents to a block in ini-styled configuration
514 files. $name should be the name of a [block], and $values is
515 assumed to be a hashref mapping key/value pairs. Also supported by
516 param() method with the help of "-block" and "-value" (or
517 "-values") options:
518 $cfg->set_block('Project', {Count=>3, 'Multiple Column' => 20});
520 # is the same as:
521 $cfg->param(-block=>'Project', -value=>{Count=>3, 'Multiple Column' => 20});
522 Warning: all the contents of a block, if previously existed will be
524 wiped out. If you want to set specific key/value pairs, use
525 explicit method:
526 $cfg->param('Project.Count', 3);
528 as_string()
530 - returns the configuration file as a chunk of text. It is the same
531 text used by write() and save() to store the new configuration file
532 back to file.
533 write()
535 - writes the configuration file into disk. Argument, if passed,
536 will be treated as the name of the file configuration variables
537 should be saved in.
538 save()
540 - same as write().
541 dump()
543 - for debugging only. Dumps the whole Config::Simple object using
544 Data::Dumper. Argument, if passed, will be treated as the name of
545 the file object should be dumped in. The second argument specifies
546 amount of indentation as documented in Data::Dumper manual. Default
547 indent size is 2.
548 error()
550 - returns the last error message from read/write or import_*
551 operations.
552
554 · Support for lines with continuation character, '\'. Currently its
555 support is restricted and quite possibly buggy.
556 · Retaining comments while writing the configuration files back
558 and/or methods for manipulating comments. Everyone loves comments!
559 · Retain the order of the blocks and other variables in the
561 configuration files.
562
564 Submit bugs and possibly patches to Sherzod B. Ruzmetov
565 <sherzodr@cpan.org>.
566
568 Michael Caldwell (mjc@mjcnet.com)
569 whitespace support, "-lc" switch and for various bug fixes
570 Scott Weinstein (Scott.Weinstein@lazard.com)
572 bug fix in TIEHASH
573 Ruslan U. Zakirov <cubic@wr.miee.ru>
575 default name space suggestion and patch
576 Hirosi Taguti
578 import_names() and import_from() idea.
579 Vitaly Kushneriuk
581 for bug fixes and suggestions
582
584 Copyright (C) 2002-2003 Sherzod B. Ruzmetov.
585 This software is free library. You can modify and/or distribute it
587 under the same terms as Perl itself
588
590 Sherzod B. Ruzmetov E<lt>sherzodr@cpan.orgE<gt>
591 URI: http://author.handalak.com
592
594 Config::General, Config::Simple, Config::Tiny
595perl v5.16.3 2006-09-12 Simple(3)