5 releases (3 stable)
1.0.3 | Feb 27, 2024 |
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1.0.1 | Jun 29, 2023 |
1.0.0 | Oct 22, 2022 |
0.3.0 | Feb 23, 2022 |
0.2.0 | Feb 1, 2022 |
#685 in Command line utilities
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70KB
1.5K
SLoC
Detect a UTF-8-capable locale for running child processes in
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Overview
Sometimes it is useful for a program to be able to run a child process and
more or less depend on its output being valid UTF-8. This can usually be
accomplished by setting one or more environment variables, but there is
the question of what to set them to - what UTF-8-capable locale is present
on this particular system? This is where the utf8_locale
module comes in.
Examples
For the Rust implementation:
use std::process;
use utf8_locale;
let utf8env = utf8_locale::Utf8Detect()::new().detect()?;
let cmd = process::Command::new(...).env_clear().envs(utf8_env.env);
For the Python implementation:
import subprocess
import utf8_locale
utf8env = utf8_locale.Utf8Detect().detect()
subprocess.check_output([...], encoding="UTF-8", env=utf8env.env)
Classes (Python and Rust)
LanguagesDetect
The detect()
method of this class examines either the provided environment
variables or the current process's environment and returns a list of language
codes in order of preference that may then be used for determining which
UTF-8-capable locale to use.
Utf8Detect
The detect()
method of this class runs the external locale
command to
obtain a list of the supported locale names, and then picks a suitable one to
use so that programs are more likely to output valid UTF-8 characters and
language-neutral messages. It prefers the C
base locale, but if neither
C.UTF-8
nor C.utf8
is available, it will fall back to a list of other
locale names that are likely to be present on the system. The list of
preferred language codes is configurable.
Functions
Note that for the Python and Rust implementation it is recommended to
use the Utf8Detect
and, if needed, the LanguagesDetect
builder classes to
perform the detection.
detect_utf8_locale()
The detect_utf8_locale()
function runs the external locale
command to
obtain a list of the supported locale names, and then picks a suitable one to
use so that programs are more likely to output valid UTF-8 characters and
language-neutral messages. It prefers the C
base locale, but if neither
C.UTF-8
nor C.utf8
is available, it will fall back to a list of other
locale names that are likely to be present on the system.
get_utf8_vars()
The get_utf8_vars()
function invokes detect_utf8_locale()
and then returns
a dictionary/hashmap containing two entries: LC_ALL
set to the obtained
locale name and LANGUAGE
set to an empty string so that recent versions of
the gettext library do not choose a different language to output messages in.
get_utf8_env()
The get_utf8_env()
function invokes detect_utf8_locale()
and then returns
a dictionary/hashmap containing the current environment variables,
LC_ALL
set to the obtained locale name, and LANGUAGE
set to an empty
string so that recent versions of the gettext library do not choose
a different language to output messages in.
get_preferred_languages()
The get_preferred_languages()
function examines either the current process
environment or the provided dictionary and returns a list of the languages
specified in the locale variables (LC_ALL
, LANG
, LC_MESSAGES
, etc).
It may be used by programs to add the user's currently preferred locale to
their own settings.
Contact
The feature-check
library was written by Peter Pentchev.
It is developed in a GitLab repository. This documentation is
hosted at Ringlet with a copy at ReadTheDocs.
Dependencies
~7.5MB
~123K SLoC