1 Navigation 2 index modules | next | previous | Python » 3.4.4 Documentation » The Python Standard Library » 14. File Formats » 3 14.2. configparser — Configuration file parser 4 This module provides the ConfigParser class which implements a basic configuration language which provides a structure similar to what’s found in Microsoft Windows INI files. You can use this to write Python programs which can be customized by end users easily. 5 6 Note 7 This library does not interpret or write the value-type prefixes used in the Windows Registry extended version of INI syntax. 8 9 See also 10 11 Module shlex 12 Support for a creating Unix shell-like mini-languages which can be used as an alternate format for application configuration files. 13 Module json 14 The json module implements a subset of JavaScript syntax which can also be used for this purpose. 15 14.2.1. Quick Start 16 Let’s take a very basic configuration file that looks like this: 17 18 [DEFAULT] 19 ServerAliveInterval = 45 20 Compression = yes 21 CompressionLevel = 9 22 ForwardX11 = yes 23 24 [bitbucket.org] 25 User = hg 26 27 [topsecret.server.com] 28 Port = 50022 29 ForwardX11 = no 30 The structure of INI files is described in the following section. Essentially, the file consists of sections, each of which contains keys with values. configparser classes can read and write such files. Let’s start by creating the above configuration file programatically. 31 32 >>> import configparser 33 >>> config = configparser.ConfigParser() 34 >>> config['DEFAULT'] = {'ServerAliveInterval': '45', 35 ... 'Compression': 'yes', 36 ... 'CompressionLevel': '9'} 37 >>> config['bitbucket.org'] = {} 38 >>> config['bitbucket.org']['User'] = 'hg' 39 >>> config['topsecret.server.com'] = {} 40 >>> topsecret = config['topsecret.server.com'] 41 >>> topsecret['Port'] = '50022' # mutates the parser 42 >>> topsecret['ForwardX11'] = 'no' # same here 43 >>> config['DEFAULT']['ForwardX11'] = 'yes' 44 >>> with open('example.ini', 'w') as configfile: 45 ... config.write(configfile) 46 ... 47 As you can see, we can treat a config parser much like a dictionary. There are differences, outlined later, but the behavior is very close to what you would expect from a dictionary. 48 49 Now that we have created and saved a configuration file, let’s read it back and explore the data it holds. 50 51 >>> import configparser 52 >>> config = configparser.ConfigParser() 53 >>> config.sections() 54 [] 55 >>> config.read('example.ini') 56 ['example.ini'] 57 >>> config.sections() 58 ['bitbucket.org', 'topsecret.server.com'] 59 >>> 'bitbucket.org' in config 60 True 61 >>> 'bytebong.com' in config 62 False 63 >>> config['bitbucket.org']['User'] 64 'hg' 65 >>> config['DEFAULT']['Compression'] 66 'yes' 67 >>> topsecret = config['topsecret.server.com'] 68 >>> topsecret['ForwardX11'] 69 'no' 70 >>> topsecret['Port'] 71 '50022' 72 >>> for key in config['bitbucket.org']: print(key) 73 ... 74 user 75 compressionlevel 76 serveraliveinterval 77 compression 78 forwardx11 79 >>> config['bitbucket.org']['ForwardX11'] 80 'yes' 81 As we can see above, the API is pretty straightforward. The only bit of magic involves the DEFAULT section which provides default values for all other sections [1]. Note also that keys in sections are case-insensitive and stored in lowercase [1]. 82 83 14.2.2. Supported Datatypes 84 Config parsers do not guess datatypes of values in configuration files, always storing them internally as strings. This means that if you need other datatypes, you should convert on your own: 85 86 >>> int(topsecret['Port']) 87 50022 88 >>> float(topsecret['CompressionLevel']) 89 9.0 90 Extracting Boolean values is not that simple, though. Passing the value to bool() would do no good since bool('False') is still True. This is why config parsers also provide getboolean(). This method is case-insensitive and recognizes Boolean values from 'yes'/'no', 'on'/'off' and '1'/'0' [1]. For example: 91 92 >>> topsecret.getboolean('ForwardX11') 93 False 94 >>> config['bitbucket.org'].getboolean('ForwardX11') 95 True 96 >>> config.getboolean('bitbucket.org', 'Compression') 97 True 98 Apart from getboolean(), config parsers also provide equivalent getint() and getfloat() methods, but these are far less useful since conversion using int() and float() is sufficient for these types. 99 100 14.2.3. Fallback Values 101 As with a dictionary, you can use a section’s get() method to provide fallback values: 102 103 >>> topsecret.get('Port') 104 '50022' 105 >>> topsecret.get('CompressionLevel') 106 '9' 107 >>> topsecret.get('Cipher') 108 >>> topsecret.get('Cipher', '3des-cbc') 109 '3des-cbc' 110 Please note that default values have precedence over fallback values. For instance, in our example the 'CompressionLevel' key was specified only in the 'DEFAULT' section. If we try to get it from the section 'topsecret.server.com', we will always get the default, even if we specify a fallback: 111 112 >>> topsecret.get('CompressionLevel', '3') 113 '9' 114 One more thing to be aware of is that the parser-level get() method provides a custom, more complex interface, maintained for backwards compatibility. When using this method, a fallback value can be provided via the fallback keyword-only argument: 115 116 >>> config.get('bitbucket.org', 'monster', 117 ... fallback='No such things as monsters') 118 'No such things as monsters' 119 The same fallback argument can be used with the getint(), getfloat() and getboolean() methods, for example: 120 121 >>> 'BatchMode' in topsecret 122 False 123 >>> topsecret.getboolean('BatchMode', fallback=True) 124 True 125 >>> config['DEFAULT']['BatchMode'] = 'no' 126 >>> topsecret.getboolean('BatchMode', fallback=True) 127 False 128 14.2.4. Supported INI File Structure 129 A configuration file consists of sections, each led by a [section] header, followed by key/value entries separated by a specific string (= or : by default [1]). By default, section names are case sensitive but keys are not [1]. Leading and trailing whitespace is removed from keys and values. Values can be omitted, in which case the key/value delimiter may also be left out. Values can also span multiple lines, as long as they are indented deeper than the first line of the value. Depending on the parser’s mode, blank lines may be treated as parts of multiline values or ignored. 130 131 Configuration files may include comments, prefixed by specific characters (# and ; by default [1]). Comments may appear on their own on an otherwise empty line, possibly indented. [1] 132 133 For example: 134 135 [Simple Values] 136 key=value 137 spaces in keys=allowed 138 spaces in values=allowed as well 139 spaces around the delimiter = obviously 140 you can also use : to delimit keys from values 141 142 [All Values Are Strings] 143 values like this: 1000000 144 or this: 3.14159265359 145 are they treated as numbers? : no 146 integers, floats and booleans are held as: strings 147 can use the API to get converted values directly: true 148 149 [Multiline Values] 150 chorus: I'm a lumberjack, and I'm okay 151 I sleep all night and I work all day 152 153 [No Values] 154 key_without_value 155 empty string value here = 156 157 [You can use comments] 158 # like this 159 ; or this 160 161 # By default only in an empty line. 162 # Inline comments can be harmful because they prevent users 163 # from using the delimiting characters as parts of values. 164 # That being said, this can be customized. 165 166 [Sections Can Be Indented] 167 can_values_be_as_well = True 168 does_that_mean_anything_special = False 169 purpose = formatting for readability 170 multiline_values = are 171 handled just fine as 172 long as they are indented 173 deeper than the first line 174 of a value 175 # Did I mention we can indent comments, too? 176 14.2.5. Interpolation of values 177 On top of the core functionality, ConfigParser supports interpolation. This means values can be preprocessed before returning them from get() calls. 178 179 class configparser.BasicInterpolation 180 The default implementation used by ConfigParser. It enables values to contain format strings which refer to other values in the same section, or values in the special default section [1]. Additional default values can be provided on initialization. 181 182 For example: 183 184 [Paths] 185 home_dir: /Users 186 my_dir: %(home_dir)s/lumberjack 187 my_pictures: %(my_dir)s/Pictures 188 In the example above, ConfigParser with interpolation set to BasicInterpolation() would resolve %(home_dir)s to the value of home_dir (/Users in this case). %(my_dir)s in effect would resolve to /Users/lumberjack. All interpolations are done on demand so keys used in the chain of references do not have to be specified in any specific order in the configuration file. 189 190 With interpolation set to None, the parser would simply return %(my_dir)s/Pictures as the value of my_pictures and %(home_dir)s/lumberjack as the value of my_dir. 191 192 class configparser.ExtendedInterpolation 193 An alternative handler for interpolation which implements a more advanced syntax, used for instance in zc.buildout. Extended interpolation is using ${section:option} to denote a value from a foreign section. Interpolation can span multiple levels. For convenience, if the section: part is omitted, interpolation defaults to the current section (and possibly the default values from the special section). 194 195 For example, the configuration specified above with basic interpolation, would look like this with extended interpolation: 196 197 [Paths] 198 home_dir: /Users 199 my_dir: ${home_dir}/lumberjack 200 my_pictures: ${my_dir}/Pictures 201 Values from other sections can be fetched as well: 202 203 [Common] 204 home_dir: /Users 205 library_dir: /Library 206 system_dir: /System 207 macports_dir: /opt/local 208 209 [Frameworks] 210 Python: 3.2 211 path: ${Common:system_dir}/Library/Frameworks/ 212 213 [Arthur] 214 nickname: Two Sheds 215 last_name: Jackson 216 my_dir: ${Common:home_dir}/twosheds 217 my_pictures: ${my_dir}/Pictures 218 python_dir: ${Frameworks:path}/Python/Versions/${Frameworks:Python} 219 14.2.6. Mapping Protocol Access 220 New in version 3.2. 221 222 Mapping protocol access is a generic name for functionality that enables using custom objects as if they were dictionaries. In case of configparser, the mapping interface implementation is using the parser['section']['option'] notation. 223 224 parser['section'] in particular returns a proxy for the section’s data in the parser. This means that the values are not copied but they are taken from the original parser on demand. What’s even more important is that when values are changed on a section proxy, they are actually mutated in the original parser. 225 226 configparser objects behave as close to actual dictionaries as possible. The mapping interface is complete and adheres to the MutableMapping ABC. However, there are a few differences that should be taken into account: 227 228 By default, all keys in sections are accessible in a case-insensitive manner [1]. E.g. for option in parser["section"] yields only optionxform‘ed option key names. This means lowercased keys by default. At the same time, for a section that holds the key 'a', both expressions return True: 229 230 "a" in parser["section"] 231 "A" in parser["section"] 232 All sections include DEFAULTSECT values as well which means that .clear() on a section may not leave the section visibly empty. This is because default values cannot be deleted from the section (because technically they are not there). If they are overridden in the section, deleting causes the default value to be visible again. Trying to delete a default value causes a KeyError. 233 234 DEFAULTSECT cannot be removed from the parser: 235 236 trying to delete it raises ValueError, 237 parser.clear() leaves it intact, 238 parser.popitem() never returns it. 239 parser.get(section, option, **kwargs) - the second argument is not a fallback value. Note however that the section-level get() methods are compatible both with the mapping protocol and the classic configparser API. 240 241 parser.items() is compatible with the mapping protocol (returns a list of section_name, section_proxy pairs including the DEFAULTSECT). However, this method can also be invoked with arguments: parser.items(section, raw, vars). The latter call returns a list of option, value pairs for a specified section, with all interpolations expanded (unless raw=True is provided). 242 243 The mapping protocol is implemented on top of the existing legacy API so that subclasses overriding the original interface still should have mappings working as expected. 244 245 14.2.7. Customizing Parser Behaviour 246 There are nearly as many INI format variants as there are applications using it. configparser goes a long way to provide support for the largest sensible set of INI styles available. The default functionality is mainly dictated by historical background and it’s very likely that you will want to customize some of the features. 247 248 The most common way to change the way a specific config parser works is to use the __init__() options: 249 250 defaults, default value: None 251 252 This option accepts a dictionary of key-value pairs which will be initially put in the DEFAULT section. This makes for an elegant way to support concise configuration files that don’t specify values which are the same as the documented default. 253 254 Hint: if you want to specify default values for a specific section, use read_dict() before you read the actual file. 255 256 dict_type, default value: collections.OrderedDict 257 258 This option has a major impact on how the mapping protocol will behave and how the written configuration files look. With the default ordered dictionary, every section is stored in the order they were added to the parser. Same goes for options within sections. 259 260 An alternative dictionary type can be used for example to sort sections and options on write-back. You can also use a regular dictionary for performance reasons. 261 262 Please note: there are ways to add a set of key-value pairs in a single operation. When you use a regular dictionary in those operations, the order of the keys may be random. For example: 263 264 >>> parser = configparser.ConfigParser() 265 >>> parser.read_dict({'section1': {'key1': 'value1', 266 ... 'key2': 'value2', 267 ... 'key3': 'value3'}, 268 ... 'section2': {'keyA': 'valueA', 269 ... 'keyB': 'valueB', 270 ... 'keyC': 'valueC'}, 271 ... 'section3': {'foo': 'x', 272 ... 'bar': 'y', 273 ... 'baz': 'z'} 274 ... }) 275 >>> parser.sections() 276 ['section3', 'section2', 'section1'] 277 >>> [option for option in parser['section3']] 278 ['baz', 'foo', 'bar'] 279 In these operations you need to use an ordered dictionary as well: 280 281 >>> from collections import OrderedDict 282 >>> parser = configparser.ConfigParser() 283 >>> parser.read_dict( 284 ... OrderedDict(( 285 ... ('s1', 286 ... OrderedDict(( 287 ... ('1', '2'), 288 ... ('3', '4'), 289 ... ('5', '6'), 290 ... )) 291 ... ), 292 ... ('s2', 293 ... OrderedDict(( 294 ... ('a', 'b'), 295 ... ('c', 'd'), 296 ... ('e', 'f'), 297 ... )) 298 ... ), 299 ... )) 300 ... ) 301 >>> parser.sections() 302 ['s1', 's2'] 303 >>> [option for option in parser['s1']] 304 ['1', '3', '5'] 305 >>> [option for option in parser['s2'].values()] 306 ['b', 'd', 'f'] 307 allow_no_value, default value: False 308 309 Some configuration files are known to include settings without values, but which otherwise conform to the syntax supported by configparser. The allow_no_value parameter to the constructor can be used to indicate that such values should be accepted: 310 311 >>> import configparser 312 313 >>> sample_config = """ 314 ... [mysqld] 315 ... user = mysql 316 ... pid-file = /var/run/mysqld/mysqld.pid 317 ... skip-external-locking 318 ... old_passwords = 1 319 ... skip-bdb 320 ... # we don't need ACID today 321 ... skip-innodb 322 ... """ 323 >>> config = configparser.ConfigParser(allow_no_value=True) 324 >>> config.read_string(sample_config) 325 326 >>> # Settings with values are treated as before: 327 >>> config["mysqld"]["user"] 328 'mysql' 329 330 >>> # Settings without values provide None: 331 >>> config["mysqld"]["skip-bdb"] 332 333 >>> # Settings which aren't specified still raise an error: 334 >>> config["mysqld"]["does-not-exist"] 335 Traceback (most recent call last): 336 ... 337 KeyError: 'does-not-exist' 338 delimiters, default value: ('=', ':') 339 340 Delimiters are substrings that delimit keys from values within a section. The first occurrence of a delimiting substring on a line is considered a delimiter. This means values (but not keys) can contain the delimiters. 341 342 See also the space_around_delimiters argument to ConfigParser.write(). 343 344 comment_prefixes, default value: ('#', ';') 345 346 inline_comment_prefixes, default value: None 347 348 Comment prefixes are strings that indicate the start of a valid comment within a config file. comment_prefixes are used only on otherwise empty lines (optionally indented) whereas inline_comment_prefixes can be used after every valid value (e.g. section names, options and empty lines as well). By default inline comments are disabled and '#' and ';' are used as prefixes for whole line comments. 349 350 Changed in version 3.2: In previous versions of configparser behaviour matched comment_prefixes=('#',';') and inline_comment_prefixes=(';',). 351 352 Please note that config parsers don’t support escaping of comment prefixes so using inline_comment_prefixes may prevent users from specifying option values with characters used as comment prefixes. When in doubt, avoid setting inline_comment_prefixes. In any circumstances, the only way of storing comment prefix characters at the beginning of a line in multiline values is to interpolate the prefix, for example: 353 354 >>> from configparser import ConfigParser, ExtendedInterpolation 355 >>> parser = ConfigParser(interpolation=ExtendedInterpolation()) 356 >>> # the default BasicInterpolation could be used as well 357 >>> parser.read_string(""" 358 ... [DEFAULT] 359 ... hash = # 360 ... 361 ... [hashes] 362 ... shebang = 363 ... ${hash}!/usr/bin/env python 364 ... ${hash} -*- coding: utf-8 -*- 365 ... 366 ... extensions = 367 ... enabled_extension 368 ... another_extension 369 ... #disabled_by_comment 370 ... yet_another_extension 371 ... 372 ... interpolation not necessary = if # is not at line start 373 ... even in multiline values = line #1 374 ... line #2 375 ... line #3 376 ... """) 377 >>> print(parser['hashes']['shebang']) 378 379 #!/usr/bin/env python 380 # -*- coding: utf-8 -*- 381 >>> print(parser['hashes']['extensions']) 382 383 enabled_extension 384 another_extension 385 yet_another_extension 386 >>> print(parser['hashes']['interpolation not necessary']) 387 if # is not at line start 388 >>> print(parser['hashes']['even in multiline values']) 389 line #1 390 line #2 391 line #3 392 strict, default value: True 393 394 When set to True, the parser will not allow for any section or option duplicates while reading from a single source (using read_file(), read_string() or read_dict()). It is recommended to use strict parsers in new applications. 395 396 Changed in version 3.2: In previous versions of configparser behaviour matched strict=False. 397 398 empty_lines_in_values, default value: True 399 400 In config parsers, values can span multiple lines as long as they are indented more than the key that holds them. By default parsers also let empty lines to be parts of values. At the same time, keys can be arbitrarily indented themselves to improve readability. In consequence, when configuration files get big and complex, it is easy for the user to lose track of the file structure. Take for instance: 401 402 [Section] 403 key = multiline 404 value with a gotcha 405 406 this = is still a part of the multiline value of 'key' 407 This can be especially problematic for the user to see if she’s using a proportional font to edit the file. That is why when your application does not need values with empty lines, you should consider disallowing them. This will make empty lines split keys every time. In the example above, it would produce two keys, key and this. 408 409 default_section, default value: configparser.DEFAULTSECT (that is: "DEFAULT") 410 411 The convention of allowing a special section of default values for other sections or interpolation purposes is a powerful concept of this library, letting users create complex declarative configurations. This section is normally called "DEFAULT" but this can be customized to point to any other valid section name. Some typical values include: "general" or "common". The name provided is used for recognizing default sections when reading from any source and is used when writing configuration back to a file. Its current value can be retrieved using the parser_instance.default_section attribute and may be modified at runtime (i.e. to convert files from one format to another). 412 413 interpolation, default value: configparser.BasicInterpolation 414 415 Interpolation behaviour may be customized by providing a custom handler through the interpolation argument. None can be used to turn off interpolation completely, ExtendedInterpolation() provides a more advanced variant inspired by zc.buildout. More on the subject in the dedicated documentation section. RawConfigParser has a default value of None. 416 417 More advanced customization may be achieved by overriding default values of these parser attributes. The defaults are defined on the classes, so they may be overridden by subclasses or by attribute assignment. 418 419 configparser.BOOLEAN_STATES 420 By default when using getboolean(), config parsers consider the following values True: '1', 'yes', 'true', 'on' and the following values False: '0', 'no', 'false', 'off'. You can override this by specifying a custom dictionary of strings and their Boolean outcomes. For example: 421 422 >>> custom = configparser.ConfigParser() 423 >>> custom['section1'] = {'funky': 'nope'} 424 >>> custom['section1'].getboolean('funky') 425 Traceback (most recent call last): 426 ... 427 ValueError: Not a boolean: nope 428 >>> custom.BOOLEAN_STATES = {'sure': True, 'nope': False} 429 >>> custom['section1'].getboolean('funky') 430 False 431 Other typical Boolean pairs include accept/reject or enabled/disabled. 432 433 configparser.optionxform(option) 434 This method transforms option names on every read, get, or set operation. The default converts the name to lowercase. This also means that when a configuration file gets written, all keys will be lowercase. Override this method if that’s unsuitable. For example: 435 436 >>> config = """ 437 ... [Section1] 438 ... Key = Value 439 ... 440 ... [Section2] 441 ... AnotherKey = Value 442 ... """ 443 >>> typical = configparser.ConfigParser() 444 >>> typical.read_string(config) 445 >>> list(typical['Section1'].keys()) 446 ['key'] 447 >>> list(typical['Section2'].keys()) 448 ['anotherkey'] 449 >>> custom = configparser.RawConfigParser() 450 >>> custom.optionxform = lambda option: option 451 >>> custom.read_string(config) 452 >>> list(custom['Section1'].keys()) 453 ['Key'] 454 >>> list(custom['Section2'].keys()) 455 ['AnotherKey'] 456 configparser.SECTCRE 457 A compiled regular expression used to parse section headers. The default matches [section] to the name "section". Whitespace is considered part of the section name, thus [ larch ] will be read as a section of name " larch ". Override this attribute if that’s unsuitable. For example: 458 459 >>> config = """ 460 ... [Section 1] 461 ... option = value 462 ... 463 ... [ Section 2 ] 464 ... another = val 465 ... """ 466 >>> typical = ConfigParser() 467 >>> typical.read_string(config) 468 >>> typical.sections() 469 ['Section 1', ' Section 2 '] 470 >>> custom = ConfigParser() 471 >>> custom.SECTCRE = re.compile(r"[ *(?P<header>[^]]+?) *]") 472 >>> custom.read_string(config) 473 >>> custom.sections() 474 ['Section 1', 'Section 2'] 475 Note 476 While ConfigParser objects also use an OPTCRE attribute for recognizing option lines, it’s not recommended to override it because that would interfere with constructor options allow_no_value and delimiters. 477 478 14.2.8. Legacy API Examples 479 Mainly because of backwards compatibility concerns, configparser provides also a legacy API with explicit get/set methods. While there are valid use cases for the methods outlined below, mapping protocol access is preferred for new projects. The legacy API is at times more advanced, low-level and downright counterintuitive. 480 481 An example of writing to a configuration file: 482 483 import configparser 484 485 config = configparser.RawConfigParser() 486 487 # Please note that using RawConfigParser's set functions, you can assign 488 # non-string values to keys internally, but will receive an error when 489 # attempting to write to a file or when you get it in non-raw mode. Setting 490 # values using the mapping protocol or ConfigParser's set() does not allow 491 # such assignments to take place. 492 config.add_section('Section1') 493 config.set('Section1', 'an_int', '15') 494 config.set('Section1', 'a_bool', 'true') 495 config.set('Section1', 'a_float', '3.1415') 496 config.set('Section1', 'baz', 'fun') 497 config.set('Section1', 'bar', 'Python') 498 config.set('Section1', 'foo', '%(bar)s is %(baz)s!') 499 500 # Writing our configuration file to 'example.cfg' 501 with open('example.cfg', 'w') as configfile: 502 config.write(configfile) 503 An example of reading the configuration file again: 504 505 import configparser 506 507 config = configparser.RawConfigParser() 508 config.read('example.cfg') 509 510 # getfloat() raises an exception if the value is not a float 511 # getint() and getboolean() also do this for their respective types 512 a_float = config.getfloat('Section1', 'a_float') 513 an_int = config.getint('Section1', 'an_int') 514 print(a_float + an_int) 515 516 # Notice that the next output does not interpolate '%(bar)s' or '%(baz)s'. 517 # This is because we are using a RawConfigParser(). 518 if config.getboolean('Section1', 'a_bool'): 519 print(config.get('Section1', 'foo')) 520 To get interpolation, use ConfigParser: 521 522 import configparser 523 524 cfg = configparser.ConfigParser() 525 cfg.read('example.cfg') 526 527 # Set the optional *raw* argument of get() to True if you wish to disable 528 # interpolation in a single get operation. 529 print(cfg.get('Section1', 'foo', raw=False)) # -> "Python is fun!" 530 print(cfg.get('Section1', 'foo', raw=True)) # -> "%(bar)s is %(baz)s!" 531 532 # The optional *vars* argument is a dict with members that will take 533 # precedence in interpolation. 534 print(cfg.get('Section1', 'foo', vars={'bar': 'Documentation', 535 'baz': 'evil'})) 536 537 # The optional *fallback* argument can be used to provide a fallback value 538 print(cfg.get('Section1', 'foo')) 539 # -> "Python is fun!" 540 541 print(cfg.get('Section1', 'foo', fallback='Monty is not.')) 542 # -> "Python is fun!" 543 544 print(cfg.get('Section1', 'monster', fallback='No such things as monsters.')) 545 # -> "No such things as monsters." 546 547 # A bare print(cfg.get('Section1', 'monster')) would raise NoOptionError 548 # but we can also use: 549 550 print(cfg.get('Section1', 'monster', fallback=None)) 551 # -> None 552 Default values are available in both types of ConfigParsers. They are used in interpolation if an option used is not defined elsewhere. 553 554 import configparser 555 556 # New instance with 'bar' and 'baz' defaulting to 'Life' and 'hard' each 557 config = configparser.ConfigParser({'bar': 'Life', 'baz': 'hard'}) 558 config.read('example.cfg') 559 560 print(config.get('Section1', 'foo')) # -> "Python is fun!" 561 config.remove_option('Section1', 'bar') 562 config.remove_option('Section1', 'baz') 563 print(config.get('Section1', 'foo')) # -> "Life is hard!" 564 14.2.9. ConfigParser Objects 565 class configparser.ConfigParser(defaults=None, dict_type=collections.OrderedDict, allow_no_value=False, delimiters=('=', ':'), comment_prefixes=('#', ';'), inline_comment_prefixes=None, strict=True, empty_lines_in_values=True, default_section=configparser.DEFAULTSECT, interpolation=BasicInterpolation()) 566 The main configuration parser. When defaults is given, it is initialized into the dictionary of intrinsic defaults. When dict_type is given, it will be used to create the dictionary objects for the list of sections, for the options within a section, and for the default values. 567 568 When delimiters is given, it is used as the set of substrings that divide keys from values. When comment_prefixes is given, it will be used as the set of substrings that prefix comments in otherwise empty lines. Comments can be indented. When inline_comment_prefixes is given, it will be used as the set of substrings that prefix comments in non-empty lines. 569 570 When strict is True (the default), the parser won’t allow for any section or option duplicates while reading from a single source (file, string or dictionary), raising DuplicateSectionError or DuplicateOptionError. When empty_lines_in_values is False (default: True), each empty line marks the end of an option. Otherwise, internal empty lines of a multiline option are kept as part of the value. When allow_no_value is True (default: False), options without values are accepted; the value held for these is None and they are serialized without the trailing delimiter. 571 572 When default_section is given, it specifies the name for the special section holding default values for other sections and interpolation purposes (normally named "DEFAULT"). This value can be retrieved and changed on runtime using the default_section instance attribute. 573 574 Interpolation behaviour may be customized by providing a custom handler through the interpolation argument. None can be used to turn off interpolation completely, ExtendedInterpolation() provides a more advanced variant inspired by zc.buildout. More on the subject in the dedicated documentation section. 575 576 All option names used in interpolation will be passed through the optionxform() method just like any other option name reference. For example, using the default implementation of optionxform() (which converts option names to lower case), the values foo %(bar)s and foo %(BAR)s are equivalent. 577 578 Changed in version 3.1: The default dict_type is collections.OrderedDict. 579 580 Changed in version 3.2: allow_no_value, delimiters, comment_prefixes, strict, empty_lines_in_values, default_section and interpolation were added. 581 582 defaults() 583 Return a dictionary containing the instance-wide defaults. 584 585 sections() 586 Return a list of the sections available; the default section is not included in the list. 587 588 add_section(section) 589 Add a section named section to the instance. If a section by the given name already exists, DuplicateSectionError is raised. If the default section name is passed, ValueError is raised. The name of the section must be a string; if not, TypeError is raised. 590 591 Changed in version 3.2: Non-string section names raise TypeError. 592 593 has_section(section) 594 Indicates whether the named section is present in the configuration. The default section is not acknowledged. 595 596 options(section) 597 Return a list of options available in the specified section. 598 599 has_option(section, option) 600 If the given section exists, and contains the given option, return True; otherwise return False. If the specified section is None or an empty string, DEFAULT is assumed. 601 602 read(filenames, encoding=None) 603 Attempt to read and parse a list of filenames, returning a list of filenames which were successfully parsed. If filenames is a string, it is treated as a single filename. If a file named in filenames cannot be opened, that file will be ignored. This is designed so that you can specify a list of potential configuration file locations (for example, the current directory, the user’s home directory, and some system-wide directory), and all existing configuration files in the list will be read. If none of the named files exist, the ConfigParser instance will contain an empty dataset. An application which requires initial values to be loaded from a file should load the required file or files using read_file() before calling read() for any optional files: 604 605 import configparser, os 606 607 config = configparser.ConfigParser() 608 config.read_file(open('defaults.cfg')) 609 config.read(['site.cfg', os.path.expanduser('~/.myapp.cfg')], 610 encoding='cp1250') 611 New in version 3.2: The encoding parameter. Previously, all files were read using the default encoding for open(). 612 613 read_file(f, source=None) 614 Read and parse configuration data from f which must be an iterable yielding Unicode strings (for example files opened in text mode). 615 616 Optional argument source specifies the name of the file being read. If not given and f has a name attribute, that is used for source; the default is '<???>'. 617 618 New in version 3.2: Replaces readfp(). 619 620 read_string(string, source='<string>') 621 Parse configuration data from a string. 622 623 Optional argument source specifies a context-specific name of the string passed. If not given, '<string>' is used. This should commonly be a filesystem path or a URL. 624 625 New in version 3.2. 626 627 read_dict(dictionary, source='<dict>') 628 Load configuration from any object that provides a dict-like items() method. Keys are section names, values are dictionaries with keys and values that should be present in the section. If the used dictionary type preserves order, sections and their keys will be added in order. Values are automatically converted to strings. 629 630 Optional argument source specifies a context-specific name of the dictionary passed. If not given, <dict> is used. 631 632 This method can be used to copy state between parsers. 633 634 New in version 3.2. 635 636 get(section, option, *, raw=False, vars=None[, fallback]) 637 Get an option value for the named section. If vars is provided, it must be a dictionary. The option is looked up in vars (if provided), section, and in DEFAULTSECT in that order. If the key is not found and fallback is provided, it is used as a fallback value. None can be provided as a fallback value. 638 639 All the '%' interpolations are expanded in the return values, unless the raw argument is true. Values for interpolation keys are looked up in the same manner as the option. 640 641 Changed in version 3.2: Arguments raw, vars and fallback are keyword only to protect users from trying to use the third argument as the fallback fallback (especially when using the mapping protocol). 642 643 getint(section, option, *, raw=False, vars=None[, fallback]) 644 A convenience method which coerces the option in the specified section to an integer. See get() for explanation of raw, vars and fallback. 645 646 getfloat(section, option, *, raw=False, vars=None[, fallback]) 647 A convenience method which coerces the option in the specified section to a floating point number. See get() for explanation of raw, vars and fallback. 648 649 getboolean(section, option, *, raw=False, vars=None[, fallback]) 650 A convenience method which coerces the option in the specified section to a Boolean value. Note that the accepted values for the option are '1', 'yes', 'true', and 'on', which cause this method to return True, and '0', 'no', 'false', and 'off', which cause it to return False. These string values are checked in a case-insensitive manner. Any other value will cause it to raise ValueError. See get() for explanation of raw, vars and fallback. 651 652 items(raw=False, vars=None) 653 items(section, raw=False, vars=None) 654 When section is not given, return a list of section_name, section_proxy pairs, including DEFAULTSECT. 655 656 Otherwise, return a list of name, value pairs for the options in the given section. Optional arguments have the same meaning as for the get() method. 657 658 Changed in version 3.2: Items present in vars no longer appear in the result. The previous behaviour mixed actual parser options with variables provided for interpolation. 659 660 set(section, option, value) 661 If the given section exists, set the given option to the specified value; otherwise raise NoSectionError. option and value must be strings; if not, TypeError is raised. 662 663 write(fileobject, space_around_delimiters=True) 664 Write a representation of the configuration to the specified file object, which must be opened in text mode (accepting strings). This representation can be parsed by a future read() call. If space_around_delimiters is true, delimiters between keys and values are surrounded by spaces. 665 666 remove_option(section, option) 667 Remove the specified option from the specified section. If the section does not exist, raise NoSectionError. If the option existed to be removed, return True; otherwise return False. 668 669 remove_section(section) 670 Remove the specified section from the configuration. If the section in fact existed, return True. Otherwise return False. 671 672 optionxform(option) 673 Transforms the option name option as found in an input file or as passed in by client code to the form that should be used in the internal structures. The default implementation returns a lower-case version of option; subclasses may override this or client code can set an attribute of this name on instances to affect this behavior. 674 675 You don’t need to subclass the parser to use this method, you can also set it on an instance, to a function that takes a string argument and returns a string. Setting it to str, for example, would make option names case sensitive: 676 677 cfgparser = ConfigParser() 678 cfgparser.optionxform = str 679 Note that when reading configuration files, whitespace around the option names is stripped before optionxform() is called. 680 681 readfp(fp, filename=None) 682 Deprecated since version 3.2: Use read_file() instead. 683 684 Changed in version 3.2: readfp() now iterates on f instead of calling f.readline(). 685 686 For existing code calling readfp() with arguments which don’t support iteration, the following generator may be used as a wrapper around the file-like object: 687 688 def readline_generator(f): 689 line = f.readline() 690 while line: 691 yield line 692 line = f.readline() 693 Instead of parser.readfp(f) use parser.read_file(readline_generator(f)). 694 695 configparser.MAX_INTERPOLATION_DEPTH 696 The maximum depth for recursive interpolation for get() when the raw parameter is false. This is relevant only when the default interpolation is used. 697 698 14.2.10. RawConfigParser Objects 699 class configparser.RawConfigParser(defaults=None, dict_type=collections.OrderedDict, allow_no_value=False, *, delimiters=('=', ':'), comment_prefixes=('#', ';'), inline_comment_prefixes=None, strict=True, empty_lines_in_values=True, default_section=configparser.DEFAULTSECT[, interpolation]) 700 Legacy variant of the ConfigParser with interpolation disabled by default and unsafe add_section and set methods. 701 702 Note 703 Consider using ConfigParser instead which checks types of the values to be stored internally. If you don’t want interpolation, you can use ConfigParser(interpolation=None). 704 705 add_section(section) 706 Add a section named section to the instance. If a section by the given name already exists, DuplicateSectionError is raised. If the default section name is passed, ValueError is raised. 707 708 Type of section is not checked which lets users create non-string named sections. This behaviour is unsupported and may cause internal errors. 709 710 set(section, option, value) 711 If the given section exists, set the given option to the specified value; otherwise raise NoSectionError. While it is possible to use RawConfigParser (or ConfigParser with raw parameters set to true) for internal storage of non-string values, full functionality (including interpolation and output to files) can only be achieved using string values. 712 713 This method lets users assign non-string values to keys internally. This behaviour is unsupported and will cause errors when attempting to write to a file or get it in non-raw mode. Use the mapping protocol API which does not allow such assignments to take place. 714 715 14.2.11. Exceptions 716 exception configparser.Error 717 Base class for all other configparser exceptions. 718 719 exception configparser.NoSectionError 720 Exception raised when a specified section is not found. 721 722 exception configparser.DuplicateSectionError 723 Exception raised if add_section() is called with the name of a section that is already present or in strict parsers when a section if found more than once in a single input file, string or dictionary. 724 725 New in version 3.2: Optional source and lineno attributes and arguments to __init__() were added. 726 727 exception configparser.DuplicateOptionError 728 Exception raised by strict parsers if a single option appears twice during reading from a single file, string or dictionary. This catches misspellings and case sensitivity-related errors, e.g. a dictionary may have two keys representing the same case-insensitive configuration key. 729 730 exception configparser.NoOptionError 731 Exception raised when a specified option is not found in the specified section. 732 733 exception configparser.InterpolationError 734 Base class for exceptions raised when problems occur performing string interpolation. 735 736 exception configparser.InterpolationDepthError 737 Exception raised when string interpolation cannot be completed because the number of iterations exceeds MAX_INTERPOLATION_DEPTH. Subclass of InterpolationError. 738 739 exception configparser.InterpolationMissingOptionError 740 Exception raised when an option referenced from a value does not exist. Subclass of InterpolationError. 741 742 exception configparser.InterpolationSyntaxError 743 Exception raised when the source text into which substitutions are made does not conform to the required syntax. Subclass of InterpolationError. 744 745 exception configparser.MissingSectionHeaderError 746 Exception raised when attempting to parse a file which has no section headers. 747 748 exception configparser.ParsingError 749 Exception raised when errors occur attempting to parse a file. 750 751 Changed in version 3.2: The filename attribute and __init__() argument were renamed to source for consistency. 752 753 Footnotes 754 755 [1] (1, 2, 3, 4, 5, 6, 7, 8, 9) Config parsers allow for heavy customization. If you are interested in changing the behaviour outlined by the footnote reference, consult the Customizing Parser Behaviour section. 756 Navigation 757 index modules | next | previous | Python » 3.4.4 Documentation » The Python Standard Library » 14. File Formats » 758 © Copyright 1990-2015, Python Software Foundation. 759 The Python Software Foundation is a non-profit corporation. Please donate. 760 Last updated on Dec 20, 2015. Found a bug? 761 Created using Sphinx 1.2.2.