KeyFile

class KeyFile(**kwargs)

GKeyFile parses .ini-like config files.

GKeyFile lets you parse, edit or create files containing groups of key-value pairs, which we call “key files” for lack of a better name. Several freedesktop.org specifications use key files now, e.g the Desktop Entry Specification and the Icon Theme Specification.

The syntax of key files is described in detail in the Desktop Entry Specification, here is a quick summary: Key files consists of groups of key-value pairs, interspersed with comments.

# this is just an example
# there can be comments before the first group

[First Group]

Name=Key File Example\tthis value shows\nescaping

# localized strings are stored in multiple key-value pairs
Welcome=Hello
Welcome[de]=Hallo
Welcome[fr_FR]=Bonjour
Welcome[it]=Ciao

[Another Group]

Numbers=2;20;-200;0

Booleans=true;false;true;true

Lines beginning with a ‘#’ and blank lines are considered comments.

Groups are started by a header line containing the group name enclosed in ‘[’ and ‘]’, and ended implicitly by the start of the next group or the end of the file. Each key-value pair must be contained in a group.

Key-value pairs generally have the form key=value, with the exception of localized strings, which have the form key[locale]=value, with a locale identifier of the form lang_COUNTRY``MODIFIER`` where COUNTRY and MODIFIER are optional. Space before and after the ‘=’ character are ignored. Newline, tab, carriage return and backslash characters in value are escaped as \n, \t, \r, and \\\\, respectively. To preserve leading spaces in values, these can also be escaped as \s.

Key files can store strings (possibly with localized variants), integers, booleans and lists of these. Lists are separated by a separator character, typically ‘;’ or ‘,’. To use the list separator character in a value in a list, it has to be escaped by prefixing it with a backslash.

This syntax is obviously inspired by the .ini files commonly met on Windows, but there are some important differences:

.ini files use the ‘;’ character to begin comments, key files use the ‘#’ character.
Key files do not allow for ungrouped keys meaning only comments can precede the first group.
Key files are always encoded in UTF-8.
Key and Group names are case-sensitive. For example, a group called [GROUP] is a different from [group].
.ini files don’t have a strongly typed boolean entry type,
they only have GetProfileInt(). In key files, only true and false (in lower case) are allowed.

Note that in contrast to the Desktop Entry Specification, groups in key files may contain the same key multiple times; the last entry wins. Key files may also contain multiple groups with the same name; they are merged together. Another difference is that keys and group names in key files are not restricted to ASCII characters.

Here is an example of loading a key file and reading a value:

g_autoptr(GError) error = NULL;
g_autoptr(GKeyFile) key_file = g_key_file_new ();

if (!g_key_file_load_from_file (key_file, "key-file.ini", flags, &error))
  {
    if (!g_error_matches (error, G_FILE_ERROR, G_FILE_ERROR_NOENT))
      g_warning ("Error loading key file: ``%s``", error->message);
    return;
  }

g_autofree gchar *val = g_key_file_get_string (key_file, "Group Name", "SomeKey", &error);
if (val == NULL &&
    !g_error_matches (error, G_KEY_FILE_ERROR, G_KEY_FILE_ERROR_KEY_NOT_FOUND))
  {
    g_warning ("Error finding key in key file: ``%s``", error->message);
    return;
  }
else if (val == NULL)
  {
    // Fall back to a default value.
    val = g_strdup ("default-value");
  }

Here is an example of creating and saving a key file:

g_autoptr(GKeyFile) key_file = g_key_file_new ();
const gchar *val = …;
g_autoptr(GError) error = NULL;

g_key_file_set_string (key_file, "Group Name", "SomeKey", val);

// Save as a file.
if (!g_key_file_save_to_file (key_file, "key-file.ini", &error))
  {
    g_warning ("Error saving key file: ``%s``", error->message);
    return;
  }

// Or store to a GBytes for use elsewhere.
gsize data_len;
g_autofree guint8 *data = (guint8 *) g_key_file_to_data (key_file, &data_len, &error);
if (data == NULL)
  {
    g_warning ("Error saving key file: ``%s``", error->message);
    return;
  }
g_autoptr(GBytes) bytes = g_bytes_new_take (g_steal_pointer (&data), data_len);

Constructors

class KeyFile

classmethod new() → KeyFile: Creates a new empty KeyFile object. Use load_from_file(), load_from_data(), load_from_dirs() or load_from_data_dirs() to read an existing key file.

Added in version 2.6.

Methods

class KeyFile

error_quark() → int

get_boolean(group_name: str, key: str) → bool

Returns the value associated with key under group_name as a boolean.

If key cannot be found then False is returned and error is set to KEY_NOT_FOUND. Likewise, if the value associated with key cannot be interpreted as a boolean then False is returned and error is set to INVALID_VALUE.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key

get_boolean_list(group_name: str, key: str) → list[bool]

Returns the values associated with key under group_name as booleans.

If key cannot be found then None is returned and error is set to KEY_NOT_FOUND. Likewise, if the values associated with key cannot be interpreted as booleans then None is returned and error is set to INVALID_VALUE.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key

get_comment(group_name: str | None = None, key: str | None = None) → str

Retrieves a comment above key from group_name. If key is None then comment will be read from above group_name. If both key and group_name are None, then comment will be read from above the first group in the file.

Note that the returned string does not include the ‘#’ comment markers, but does include any whitespace after them (on each line). It includes the line breaks between lines, but does not include the final line break.

Added in version 2.6.

Parameters:

group_name – a group name, or None
key – a key

get_double(group_name: str, key: str) → float

Returns the value associated with key under group_name as a double. If group_name is None, the start_group is used.

If key cannot be found then 0.0 is returned and error is set to KEY_NOT_FOUND. Likewise, if the value associated with key cannot be interpreted as a double then 0.0 is returned and error is set to INVALID_VALUE.

Added in version 2.12.

Parameters:

group_name – a group name
key – a key

get_double_list(group_name: str, key: str) → list[float]

Returns the values associated with key under group_name as doubles.

If key cannot be found then None is returned and error is set to KEY_NOT_FOUND. Likewise, if the values associated with key cannot be interpreted as doubles then None is returned and error is set to INVALID_VALUE.

Added in version 2.12.

Parameters:

group_name – a group name
key – a key

get_groups() → tuple[list[str], int]: Returns all groups in the key file loaded with key_file. The array of returned groups will be None-terminated, so length may optionally be None.

Added in version 2.6.

get_int64(group_name: str, key: str) → int

Returns the value associated with key under group_name as a signed 64-bit integer. This is similar to get_integer() but can return 64-bit results without truncation.

Added in version 2.26.

Parameters:

group_name – a non-None group name
key – a non-None key

get_integer(group_name: str, key: str) → int

Returns the value associated with key under group_name as an integer.

If key cannot be found then 0 is returned and error is set to KEY_NOT_FOUND. Likewise, if the value associated with key cannot be interpreted as an integer, or is out of range for a int, then 0 is returned and error is set to INVALID_VALUE.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key

get_integer_list(group_name: str, key: str) → list[int]

Returns the values associated with key under group_name as integers.

If key cannot be found then None is returned and error is set to KEY_NOT_FOUND. Likewise, if the values associated with key cannot be interpreted as integers, or are out of range for int, then None is returned and error is set to INVALID_VALUE.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key

get_keys(group_name: str) → tuple[list[str], int]

Returns all keys for the group name group_name. The array of returned keys will be None-terminated, so length may optionally be None. In the event that the group_name cannot be found, None is returned and error is set to GROUP_NOT_FOUND.

Added in version 2.6.

Parameters:: group_name – a group name

get_locale_for_key(group_name: str, key: str, locale: str | None = None) → str | None

Returns the actual locale which the result of get_locale_string() or get_locale_string_list() came from.

If calling get_locale_string() or get_locale_string_list() with exactly the same key_file, group_name, key and locale, the result of those functions will have originally been tagged with the locale that is the result of this function.

Added in version 2.56.

Parameters:

group_name – a group name
key – a key
locale – a locale identifier or None

get_locale_string(group_name: str, key: str, locale: str | None = None) → str

Returns the value associated with key under group_name translated in the given locale if available. If locale is None then the current locale is assumed.

If locale is to be non-None, or if the current locale will change over the lifetime of the KeyFile, it must be loaded with KEEP_TRANSLATIONS in order to load strings for all locales.

If key cannot be found then None is returned and error is set to KEY_NOT_FOUND. If the value associated with key cannot be interpreted or no suitable translation can be found then the untranslated value is returned.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key
locale – a locale identifier or None

get_locale_string_list(group_name: str, key: str, locale: str | None = None) → list[str]

Returns the values associated with key under group_name translated in the given locale if available. If locale is None then the current locale is assumed.

If locale is to be non-None, or if the current locale will change over the lifetime of the KeyFile, it must be loaded with KEEP_TRANSLATIONS in order to load strings for all locales.

If key cannot be found then None is returned and error is set to KEY_NOT_FOUND. If the values associated with key cannot be interpreted or no suitable translations can be found then the untranslated values are returned. The returned array is None-terminated, so length may optionally be None.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key
locale – a locale identifier or None

get_start_group() → str | None: Returns the name of the start group of the file.

Added in version 2.6.

get_string(group_name: str, key: str) → str

Returns the string value associated with key under group_name. Unlike get_value(), this function handles escape sequences like s.

In the event the key cannot be found, None is returned and error is set to KEY_NOT_FOUND. In the event that the group_name cannot be found, None is returned and error is set to GROUP_NOT_FOUND.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key

get_string_list(group_name: str, key: str) → list[str]

Returns the values associated with key under group_name.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key

get_uint64(group_name: str, key: str) → int

Returns the value associated with key under group_name as an unsigned 64-bit integer. This is similar to get_integer() but can return large positive results without truncation.

Added in version 2.26.

Parameters:

group_name – a non-None group name
key – a non-None key

get_value(group_name: str, key: str) → str

Returns the raw value associated with key under group_name. Use get_string() to retrieve an unescaped UTF-8 string.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key

has_group(group_name: str) → bool

Looks whether the key file has the group group_name.

Added in version 2.6.

Parameters:: group_name – a group name

load_from_bytes(bytes: Bytes, flags: KeyFileFlags) → bool

Loads a key file from the data in bytes into an empty KeyFile structure. If the object cannot be created then %error is set to a GKeyFileError.

Added in version 2.50.

Parameters:

bytes – a Bytes
flags – flags from KeyFileFlags

load_from_data(data: str, length: int, flags: KeyFileFlags) → bool

Loads a key file from memory into an empty KeyFile structure. If the object cannot be created then %error is set to a GKeyFileError.

Added in version 2.6.

Parameters:

data – key file loaded in memory
length – the length of data in bytes (or (gsize)-1 if data is nul-terminated)
flags – flags from KeyFileFlags

load_from_data_dirs(file: str, flags: KeyFileFlags) → tuple[bool, str]

This function looks for a key file named file in the paths returned from get_user_data_dir() and get_system_data_dirs(), loads the file into key_file and returns the file’s full path in full_path. If the file could not be loaded then an %error is set to either a FileError or GKeyFileError.

Added in version 2.6.

Parameters:

file – a relative path to a filename to open and parse
flags – flags from KeyFileFlags

load_from_dirs(file: str, search_dirs: Sequence[str], flags: KeyFileFlags) → tuple[bool, str]

This function looks for a key file named file in the paths specified in search_dirs, loads the file into key_file and returns the file’s full path in full_path.

If the file could not be found in any of the search_dirs, NOT_FOUND is returned. If the file is found but the OS returns an error when opening or reading the file, a %G_FILE_ERROR is returned. If there is a problem parsing the file, a %G_KEY_FILE_ERROR is returned.

Added in version 2.14.

Parameters:

file – a relative path to a filename to open and parse
search_dirs – None-terminated array of directories to search
flags – flags from KeyFileFlags

load_from_file(file: str, flags: KeyFileFlags) → bool

Loads a key file into an empty KeyFile structure.

If the OS returns an error when opening or reading the file, a %G_FILE_ERROR is returned. If there is a problem parsing the file, a %G_KEY_FILE_ERROR is returned.

This function will never return a NOT_FOUND error. If the file is not found, NOENT is returned.

Added in version 2.6.

Parameters:

file – the path of a filename to load, in the GLib filename encoding
flags – flags from KeyFileFlags

remove_comment(group_name: str | None = None, key: str | None = None) → bool

Removes a comment above key from group_name. If key is None then comment will be removed above group_name. If both key and group_name are None, then comment will be removed above the first group in the file.

Added in version 2.6.

Parameters:

group_name – a group name, or None
key – a key

remove_group(group_name: str) → bool

Removes the specified group, group_name, from the key file.

Added in version 2.6.

Parameters:: group_name – a group name

remove_key(group_name: str, key: str) → bool

Removes key in group_name from the key file.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key name to remove

save_to_file(filename: str) → bool

Writes the contents of key_file to filename using file_set_contents(). If you need stricter guarantees about durability of the written file than are provided by file_set_contents(), use file_set_contents_full() with the return value of to_data().

This function can fail for any of the reasons that file_set_contents() may fail.

Added in version 2.40.

Parameters:: filename – the name of the file to write to

set_boolean(group_name: str, key: str, value: bool) → None

Associates a new boolean value with key under group_name. If key cannot be found then it is created.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key
value – True or False

set_boolean_list(group_name: str, key: str, list: Sequence[bool]) → None

Associates a list of boolean values with key under group_name. If key cannot be found then it is created. If group_name is None, the start_group is used.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key
list – an array of boolean values

set_comment(group_name: str | None, key: str | None, comment: str) → bool

Places a comment above key from group_name.

If key is None then comment will be written above group_name. If both key and group_name are None, then comment will be written above the first group in the file.

Note that this function prepends a ‘#’ comment marker to each line of comment.

Added in version 2.6.

Parameters:

group_name – a group name, or None
key – a key
comment – a comment

set_double(group_name: str, key: str, value: float) → None

Associates a new double value with key under group_name. If key cannot be found then it is created.

Added in version 2.12.

Parameters:

group_name – a group name
key – a key
value – a double value

set_double_list(group_name: str, key: str, list: Sequence[float]) → None

Associates a list of double values with key under group_name. If key cannot be found then it is created.

Added in version 2.12.

Parameters:

group_name – a group name
key – a key
list – an array of double values

set_int64(group_name: str, key: str, value: int) → None

Associates a new integer value with key under group_name. If key cannot be found then it is created.

Added in version 2.26.

Parameters:

group_name – a group name
key – a key
value – an integer value

set_integer(group_name: str, key: str, value: int) → None

Associates a new integer value with key under group_name. If key cannot be found then it is created.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key
value – an integer value

set_integer_list(group_name: str, key: str, list: Sequence[int]) → None

Associates a list of integer values with key under group_name. If key cannot be found then it is created.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key
list – an array of integer values

set_list_separator(separator: int) → None

Sets the character which is used to separate values in lists. Typically ‘;’ or ‘,’ are used as separators. The default list separator is ‘;’.

Added in version 2.6.

Parameters:: separator – the separator

set_locale_string(group_name: str, key: str, locale: str, string: str) → None

Associates a string value for key and locale under group_name. If the translation for key cannot be found then it is created.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key
locale – a locale identifier
string – a string

set_locale_string_list(group_name: str, key: str, locale: str, list: Sequence[str]) → None

Associates a list of string values for key and locale under group_name. If the translation for key cannot be found then it is created.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key
locale – a locale identifier
list – a None-terminated array of locale string values

set_string(group_name: str, key: str, string: str) → None

Associates a new string value with key under group_name. If key cannot be found then it is created. If group_name cannot be found then it is created. Unlike set_value(), this function handles characters that need escaping, such as newlines.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key
string – a string

set_string_list(group_name: str, key: str, list: Sequence[str]) → None

Associates a list of string values for key under group_name. If key cannot be found then it is created. If group_name cannot be found then it is created.

Added in version 2.6.

Parameters:

group_name – a group name
key – a key
list – an array of string values

set_uint64(group_name: str, key: str, value: int) → None

Associates a new integer value with key under group_name. If key cannot be found then it is created.

Added in version 2.26.

Parameters:

group_name – a group name
key – a key
value – an integer value

set_value(group_name: str, key: str, value: str) → None

Associates a new value with key under group_name.

If key cannot be found then it is created. If group_name cannot be found then it is created. To set an UTF-8 string which may contain characters that need escaping (such as newlines or spaces), use set_string().

Added in version 2.6.

Parameters:

group_name – a group name
key – a key
value – a string

to_data() → tuple[str, int]

This function outputs key_file as a string.

Note that this function never reports an error, so it is safe to pass None as error.

Added in version 2.6.