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:
15 $cfg = new Config::Simple('app.ini');
16 # accessing values:
18 $user = $cfg->param('User');
19 # getting the values as a hash:
21 %Config = $cfg->vars();
22 # updating value with a string
24 $cfg->param('User', 'sherzodR');
25 # updating a value with an array:
27 $cfg->param('Users', ['sherzodR', 'geek', 'merlyn']);
28 # adding a new block to an ini-file:
30 $cfg->param(-block=>'last-access', -values=>{'time'=>time()});
31 # accessing a block of an ini-file;
33 $mysql = $cfg->param(-block=>'mysql');
34 # saving the changes back to file:
36 $cfg->save();
37 # --- tie() interface
39 tie %Config, "Config::Simple", 'app.ini';
40
42 Reading and writing configuration files is one of the most frequent
43 tasks of any software design. Config::Simple is the library that helps
44 you with it.
45 Config::Simple is a class representing configuration file object. It
47 supports several configuration file syntax and tries to identify the
48 file syntax automatically. Library supports parsing, updating and cre‐
49 ating configuration files.
50
52 Keeping configurable variables in your program source code is ugly,
53 really. And for people without much of a programming experience, con‐
54 figuring your programs is like performing black magic. Besides, if you
55 need to access these values from within multiple files, want your pro‐
56 grams to be able to update configuration files or want to provide a
57 friendlier user interface for your configuration files, you just have
58 to store them in an external file. That's where Config::Simple comes
59 into play, making it very easy to read and write configuration files.
60 If you have never used configuration files before, here is a brief
62 overview of various syntax to choose from. Otherwise you can jump to
63 "PROGRAMMING STYLE".
64 SIMPLE CONFIGURATION FILE
66 Simple syntax is what you need for most of your projects. These are, as
68 the name asserts, the simplest. File consists of key/value pairs,
69 delimited by nothing but white space. Keys (variables) should be
70 strictly alpha-numeric with possible dashes (-). Values can hold any
71 arbitrary text. Here is an example of such a configuration file:
72 Alias /exec
74 TempFile /usr/tmp
75 Comments start with a pound ('#') sign and cannot share the same line
77 with other configuration data.
78 HTTP-LIKE SYNTAX
80 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
96 organized in blocks. Each key/value pair is delimited with an equal (=)
97 sign. Blocks are declared on their own lines enclosed in '[' and ']':
98 [BLOCK1]
100 KEY1=VALUE1
101 KEY2=VALUE2
102 [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
125 they don't have any block declarations. This style is handy if you do
126 not want any categorization in your configuration file, but still want
127 to use '=' delimited key/value pairs. While working with such files,
128 Config::Simple assigns them to a default block, called 'default' by
129 default :-).
130 url = "http://www.handalak.com"
132 Comments can begin with either pound ('#') or semi-colon (';'). Each
134 comment should reside on its own line
135
137 Most of the programs simply need to be able to read settings from a
138 configuration file and assign them to a hash. If that's all you need,
139 you can simply use its import_from() - class method with the name of
140 the configuration file and a reference to an existing (possibly empty)
141 hash:
142 Config::Simple->import_from('myconf.cfg', \%Config);
144 Now your hash %Config holds all the configuration file's key/value
146 pairs. Keys of a hash are variable names inside your configuration
147 file, and values are their respective values. If "myconf.cfg" was a
148 traditional ini-file, keys of the hash consist of block name and vari‐
149 able delimited with a dot, such as "block.var".
150 If that's all you need, you can stop right here. Otherwise, read on.
152 There is much more Config::Simple offers.
153 READING THE CONFIGURATION FILE
155 To be able to use more features of the library, you will need to use
157 its object interface:
158 $cfg = new Config::Simple('app.cfg');
160 The above line reads and parses the configuration file accordingly. It
162 tries to guess which syntax is used by passing the file to guess_syn‐
163 tax() method. Alternatively, you can create an empty object, and only
164 then read the configuration file in:
165 $cfg = new Config::Simple();
167 $cfg->read('app.cfg');
168 As in the first example, read() also calls guess_syntax() method on the
170 file.
171 If, for any reason, it fails to guess the syntax correctly (which is
173 less likely), you can try to debug by using its guess_syntax() method.
174 It expects file handle for a configuration file and returns the name
175 of a syntax. Return value is one of "ini", "simple" or "http".
176 open(FH, "app.cfg");
178 printf("This file uses '%s' syntax\n", $cfg->guess_syntax(\*FH));
179 ACCESSING VALUES
181 After you read the configuration file in successfully, you can use
183 param() method to access the configuration values. For example:
184 $user = $cfg->param("User");
186 will return the value of "User" from either simple configuration file,
188 or http-styled configuration as well as simplified ini-files. To access
189 the value from a traditional ini-file, consider the following syntax:
190 $user = $cfg->param("mysql.user");
192 The above returns the value of "user" from within "[mysql]" block.
194 Notice the use of dot "." to delimit block and key names.
195 Config::Simple also supports vars() method, which, depending on the
197 context used, returns all the values either as hashref or hash:
198 my %Config = $cfg->vars();
200 print "Username: $Config{User}";
201 # If it was a traditional ini-file:
203 print "Username: $Config{'mysql.user'}";
204 If you call vars() in scalar context, you will end up with a reference
206 to a hash:
207 my $Config = $cfg->vars();
209 print "Username: $Config->{User}";
210 If you know what you're doing, you can also have an option of importing
212 all the names from the configuration file into your current name space
213 as global variables. All the block/key names will be uppercased and
214 will be converted to Perl's valid variable names; that is, all the dots
215 (block-key separator) and other '\W' characters will be substituted
216 with underscore '_':
217 $cfg = new Config::Simple('app.cfg');
219 $cfg->import_names();
220 # or, with a single line:
222 Config::Simple->new('app.cfg')->import_names();
223 print STDERR "Debugging mode is on" if $DEBUG_MODE;
225 In the above example, if there was a variable 'mode' under '[debug]'
227 block, it will be now accessible via $DEBUG_MODE, as opposed to
228 $cfg->param('debug.mode');
229 "import_names()" by default imports the values to its caller's name
231 space. Optionally, you can specify where to import the values by pass‐
232 ing the name of the name space as the first argument. It also prevents
233 potential name collisions:
234 Config::Simple->new('app.cfg')->import_names('CFG');
236 print STDERR "Debugging mode is on" if $CFG::DEBUG_MODE;
237 If all you want is to import values from a configuration file, the
239 above syntax may still seem longer than necessary. That's why Con‐
240 fig::Simple supports import_from() - class method, which is called with
241 the name of the configuration file. It will call import_names() for
242 you:
243 Config::Simple->import_from('app.cfg');
245 The above line imports all the variables into the caller's name space.
247 It's similar to calling import_names() on an object. If you pass a
248 string as the second argument, it will treat it as the alternative name
249 space to import the names into. As we already showed in the very first
250 example, you can also pass a reference to an existing hash as the sec‐
251 ond argument. In this case, that hash will be modified with the values
252 of the configuration file.
253 # import into $CFG name space:
255 Config::Simple->import_from('app.cfg', 'CFG');
256 # import into %Config hash:
258 Config::Simple->import_from('app.cfg', \%Config);
259 The above line imports all the values to 'CFG' name space.
261 import_from() returns underlying Config::Simple object (which you may
262 not even need anymore):
263 $cfg = Config::Simple->import_from('app.cfg', \my %Config);
265 $cfg->write('app.cfg.bak');
266 UPDATING THE VALUES
268 Configuration values, once read into Config::Simple, can be updated
270 from within your program by using the same param() method used for
271 accessing them. For example:
272 $cfg->param("User", "sherzodR");
274 The above line changes the value of "User" to "sherzodR". Similar syn‐
276 tax is applicable for ini-files as well:
277 $cfg->param("mysql.user", "sherzodR");
279 If the key you're trying to update does not exist, it will be created.
281 For example, to add a new "[session]" block to your ini-file, assuming
282 this block doesn't already exist:
283 $cfg->param("session.life", "+1M");
285 You can also delete values calling delete() method with the name of the
287 variable:
288 $cfg->delete('mysql.user'); # deletes 'user' under [mysql] block
290 SAVING/WRITING CONFIGURATION FILES
292 The above updates to the configuration values are in-memory operations.
294 They do not reflect in the file itself. To modify the files accord‐
295 ingly, you need to call either "write()" or "save()" methods on the
296 object:
297 $cfg->write();
299 The above line writes the modifications to the configuration file.
301 Alternatively, you can pass a name to either write() or save() to indi‐
302 cate the name of the file to create instead of modifying existing con‐
303 figuration file:
304 $cfg->write("app.cfg.bak");
306 If you want the changes saved at all times, you can turn "autosave"
308 mode on by passing true value to $cfg->autosave(). It will make sure
309 before your program is terminated, all the configuration values are
310 written back to its file:
311 $cfg = new Config::Simple('aff.cfg');
313 $cfg->autosave(1);
314 CREATING CONFIGURATION FILES
316 Occasionally, your programs may want to create their own configuration
318 files on the fly, possibly from a user input. To create a configuration
319 file from scratch using Config::Simple, simply create an empty configu‐
320 ration file object and define your syntax. You can do it by either
321 passing "syntax" option to new(), or by calling syntax() method. Then
322 play with param() method as you normally would. When you're done, call
323 write() method with the name of the configuration file:
324 $cfg = new Config::Simple(syntax=>'ini');
326 # or you could also do:
327 # $cfg->autosave('ini')
328 $cfg->param("mysql.dsn", "DBI:mysql:db;host=handalak.com");
330 $cfg->param("mysql.user", "sherzodr");
331 $cfg->param("mysql.pass", 'marley01');
332 $cfg->param("site.title", 'sherzodR "The Geek"');
333 $cfg->write("new.cfg");
334 This creates a file "new.cfg" with the following content:
336 ; Config::Simple 4.43
338 ; Sat Mar 8 00:32:49 2003
339 [site]
341 title=sherzodR "The Geek"
342 [mysql]
344 pass=marley01
345 dsn=DBI:mysql:db;host=handalak.com
346 user=sherzodr
347 Neat, huh? Supported syntax keywords are "ini", "simple" or "http".
349 Currently there is no support for creating simplified ini-files.
350 MULTIPLE VALUES
352 Ever wanted to define array of values in your single configuration
354 variable? I have! That's why Config::Simple supports this fancy fea‐
355 ture as well. Simply separate your values with a comma:
356 Files hp.cgi, template.html, styles.css
358 Now param() method returns an array of values:
360 @files = $cfg->param("Files");
362 unlink $_ for @files;
363 If you want a comma as part of a value, enclose the value(s) in double
365 quotes:
366 CVSFiles "hp.cgi,v", "template.html,v", "styles.css,v"
368 In case you want either of the values to hold literal quote ("), you
370 can escape it with a backlash:
371 SiteTitle "sherzod \"The Geek\""
373 TIE INTERFACE
375 If OO style intimidates you, and "import_from()" is too simple for you,
377 Config::Simple also supports tie() interface. This interface allows you
378 to tie() an ordinary Perl hash to the configuration file. From that
379 point on, you can use the variable as an ordinary Perl hash.
380 tie %Config, "Config::Simple", 'app.cfg';
382 # Using %Config as an ordinary hash
384 print "Username is '$Config{User}'\n";
385 $Config{User} = 'sherzodR';
386 The difference between "import_from($file, \%Hash)" is, all the changes
388 you make to the hash after tie()ing it, will also reflect in the con‐
389 figuration file object. If autosave() was turned on, they will also be
390 written back to file:
391 tie %Config, "Config::Simple", "app.cfg";
393 tied(%Config)->autosave(1);
394 To access the method provided in OO syntax, you need to get underlying
396 Config::Simple object. You can do so with tied() function:
397 tied(%Config)->write();
399 WARNING: tie interface is experimental and not well tested yet. Let me
401 know if you encounter a problem.
402
404 CASE SENSITIVITY
405 By default, configuration file keys and values are case sensitive.
407 Which means, $cfg->param("User") and $cfg->param("user") are referring
408 to two different values. But it is possible to force Config::Simple to
409 ignore cases all together by enabling "-lc" switch while loading the
410 library:
411 use Config::Simple ('-lc');
413 WARNING: If you call write() or save(), while working on "-lc" mode,
415 all the case information of the original file will be lost. So use it
416 if you know what you're doing.
417 USING QUOTES
419 Some people suggest if values consist of none alpha-numeric strings,
421 they should be enclosed in double quotes. Well, says them! Although
422 Config::Simple supports parsing such configuration files already, it
423 doesn't follow this rule while writing them. If you really need it to
424 generate such compatible configuration files, "-strict" switch is what
425 you need:
426 use Config::Simple '-strict';
428 Now, when you write the configuration data back to files, if values
430 hold any none alpha-numeric strings, they will be quoted accordingly.
431 All the double quotes that are part of the value will be escaped with a
432 backslash.
433 EXCEPTION HANDLING
435 Config::Simple doesn't believe in dying that easily (unless you insult
437 it using wrong syntax). It leaves the decision to the programmer
438 implementing the library. You can use its error() - class method to
439 access underlying error message. Methods that require you to check for
440 their return values are read() and write(). If you pass filename to
441 new(), you will need to check its return value as well. They return any
442 true value indicating success, undef otherwise:
443 # following new() always returns true:
445 $cfg = new Config::Simple();
446 # read() can fail:
448 $cfg->read('app.cfg') or die $cfg->error();
449 # following new() can fail:
451 $cfg = new Config::Simple('app.cfg') or die Config::Simple->error();
452 # import_from() calls read(), so it can fail:
454 Config::Simple->import_from('app.cfg', \%Config) or die Config::Simple->error();
455 # write() may fail:
457 $cfg->write() or die $cfg->error();
458 # tie() may fail, since it calls new() with a filename
460 tie %Config, "Config::Simple", 'app.cfg' or die Config::Simple->error();
461
463 new()
464 - constructor. Optionally accepts several arguments. Returns Con‐
465 fig::Simple object. Supported arguments are filename, syntax,
466 autosave. If there is a single argument, will be treated as the
467 name of the configuration file.
468 autosave([$bool])
470 - turns 'autosave' mode on if passed true argument. Returns current
471 autosave mode if used without arguments. In 'autosave' mode Con‐
472 fig::Simple writes all the changes back to its file without you
473 having to call write() or save()
474 read()
476 - accepts name of the configuration file to parse. Before that, it
477 tries to guess the syntax of the file by calling guess_syntax()
478 method. Then calls either of parse_ini_file(), parse_cfg_file() or
479 parse_http_file() accordingly. If the name of the file is provided
480 to the constructor - new(), there is no need to call read().
481 param([$name], [$value])
483 - used for accessing and updating configuration variables. If used
484 with no arguments returns all the available names from the configu‐
485 ration file.
486 delete($name)
488 - deletes a variable from a configuration file. $name has the same
489 meaning and syntax as it does in param($name)
490 clear()
492 - clears all the data from the object. Calling save() or turning
493 autosave() on results in an empty configuration file as well.
494 vars()
496 - depending on the context used, returns all the values available
497 in the configuration file either as a hash or a reference to a hash
498 import_names([$NS])
500 - imports all the names from the configuration file to the caller's
501 name space. Optional argument, if passed, will be treated as the
502 name space variables to be imported into. All the names will be
503 uppercased. Non-alphanumeric strings in the values will be under‐
504 scored
505 import_from($file, \%hash ⎪ $NS)
507 - class method. If the second argument is a reference to an exist‐
508 ing hash, it will load all the configuration contents into that
509 hash. If the second argument is a string, it will be treated as the
510 name space variables should be imported into, just like
511 import_names() does.
512 get_block($name)
514 is mostly used for accessing blocks in ini-styled configuration
515 files. Returns a hashref of all the key/value pairs of a given
516 block. Also supported by param() method with the help of "-block"
517 option:
518 $hash = $cfg->get_block('Project');
520 # is the same as saying:
521 $hash = $cfg->param(-block=>'Project');
522 set_block($name, $values)
524 used in assigning contents to a block in ini-styled configuration
525 files. $name should be the name of a [block], and $values is
526 assumed to be a hashref mapping key/value pairs. Also supported by
527 param() method with the help of "-block" and "-value" (or "-val‐
528 ues") options:
529 $cfg->set_block('Project', {Count=>3, 'Multiple Column' => 20});
531 # is the same as:
532 $cfg->param(-block=>'Project', -value=>{Count=>3, 'Multiple Column' => 20});
533 Warning: all the contents of a block, if previously existed will be
535 wiped out. If you want to set specific key/value pairs, use
536 explicit method:
537 $cfg->param('Project.Count', 3);
539 as_string()
541 - returns the configuration file as a chunk of text. It is the same
542 text used by write() and save() to store the new configuration file
543 back to file.
544 write()
546 - writes the configuration file into disk. Argument, if passed,
547 will be treated as the name of the file configuration variables
548 should be saved in.
549 save()
551 - same as write().
552 dump()
554 - for debugging only. Dumps the whole Config::Simple object using
555 Data::Dumper. Argument, if passed, will be treated as the name of
556 the file object should be dumped in. The second argument specifies
557 amount of indentation as documented in Data::Dumper manual. Default
558 indent size is 2.
559 error()
561 - returns the last error message from read/write or import_* opera‐
562 tions.
563
565 · Support for lines with continuation character, '\'. Currently its
566 support is restricted and quite possibly buggy.
567 · Retaining comments while writing the configuration files back
569 and/or methods for manipulating comments. Everyone loves comments!
570 · Retain the order of the blocks and other variables in the configu‐
572 ration files.
573
575 Submit bugs and possibly patches to Sherzod B. Ruzmetov <sher‐
576 zodr@cpan.org>.
577
579 Michael Caldwell (mjc@mjcnet.com)
580 whitespace support, "-lc" switch and for various bug fixes
581 Scott Weinstein (Scott.Weinstein@lazard.com)
583 bug fix in TIEHASH
584 Ruslan U. Zakirov <cubic@wr.miee.ru>
586 default name space suggestion and patch
587 Hirosi Taguti
589 import_names() and import_from() idea.
590 Vitaly Kushneriuk
592 for bug fixes and suggestions
593
595 Copyright (C) 2002-2003 Sherzod B. Ruzmetov.
596 This software is free library. You can modify and/or distribute it
598 under the same terms as Perl itself
599
601 Sherzod B. Ruzmetov E<lt>sherzodr@cpan.orgE<gt>
602 URI: http://author.handalak.com
603
605 Config::General, Config::Simple, Config::Tiny
606perl v5.8.8 2006-09-12 Simple(3)