"""
Simple ways to interact with the commandline without defining a full blown
CLI. These are usually used for developer hacks. Any real interface should
probably be defined using :py:mod:`argparse`, :py:mod:`click`, or
:py:mod:`scriptconfig`. Be sure to ignore unknown arguments if you use them in
conjunction with these functions.
The :func:`argflag` function checks if a boolean ``--flag`` style CLI argument
exists on the command line.
The :func:`argval` function returns the value of a ``--key=value`` style CLI
argument.
"""
import sys
from ubelt import util_const
__all__ = ['argval', 'argflag']
[docs]
def argval(key, default=util_const.NoParam, argv=None):
"""
Get the value of a keyword argument specified on the command line.
Values can be specified as ``<key> <value>`` or ``<key>=<value>``
The use-case for this function is to add hidden command line feature where
a developer can pass in a special value. This can be used to prototype a
command line interface, provide an easter egg, or add some other command
line parsing that wont be exposed in CLI help docs.
Args:
key (str | Tuple[str, ...]):
string or tuple of strings. Each key should be prefixed with two
hyphens (i.e. ``--``)
default (T | NoParamType, default=NoParam):
a value to return if not specified.
argv (List[str] | None, default=None):
uses ``sys.argv`` if unspecified
Returns:
str | T:
value - the value specified after the key. It they key is specified
multiple times, then the first value is returned.
TODO:
- [x] Can we handle the case where the value is a list of long paths? - No
- [ ] Should we default the first or last specified instance of the flag.
CommandLine:
xdoctest -m ubelt.util_arg argval:0
xdoctest -m ubelt.util_arg argval:0 --devval
xdoctest -m ubelt.util_arg argval:0 --devval=1
xdoctest -m ubelt.util_arg argval:0 --devval=2
xdoctest -m ubelt.util_arg argval:0 --devval 3
xdoctest -m ubelt.util_arg argval:0 --devval "4 5 6"
Example:
>>> # Everyday usage of this function might look like this where
>>> import ubelt as ub
>>> # grab a key/value pair if is given on the command line
>>> value = ub.argval('--devval', default='1')
>>> print('Checking if the hidden CLI key/value pair is given')
>>> if value != '1':
>>> print(ub.color_text(
>>> 'A hidden developer secret: {!r}'.format(value), 'yellow'))
>>> print('Pass the hidden CLI key/value pair to see a secret message')
Example:
>>> import ubelt as ub
>>> argv = ['--ans', '42', '--quest=the grail', '--ans=6', '--bad']
>>> assert ub.argval('--spam', argv=argv) == ub.NoParam
>>> assert ub.argval('--quest', argv=argv) == 'the grail'
>>> assert ub.argval('--ans', argv=argv) == '42'
>>> assert ub.argval('--bad', argv=argv) == ub.NoParam
>>> assert ub.argval(('--bad', '--bar'), argv=argv) == ub.NoParam
Example:
>>> # Test fix for GH Issue #41
>>> import ubelt as ub
>>> argv = ['--path=/path/with/k=3']
>>> ub.argval('--path', argv=argv) == '/path/with/k=3'
"""
if argv is None: # nocover
argv = sys.argv
keys = [key] if isinstance(key, str) else key
n_max = len(argv) - 1
for argx, item in enumerate(argv):
for key_ in keys:
if item == key_:
if argx < n_max:
value = argv[argx + 1]
return value
elif item.startswith(key_ + '='):
value = '='.join(item.split('=')[1:])
return value
value = default
return value
[docs]
def argflag(key, argv=None):
"""
Determines if a key is specified on the command line.
This is a functional alternative to ``key in sys.argv``, but it also allows
for multiple aliases of the same flag to be specified.
Args:
key (str | Tuple[str, ...]):
string or tuple of strings. Each key should be prefixed with two
hyphens (i.e. ``--``).
argv (List[str] | None, default=None): overrides ``sys.argv`` if specified
Returns:
bool: flag - True if the key (or any of the keys) was specified
CommandLine:
xdoctest -m ubelt.util_arg argflag:0
xdoctest -m ubelt.util_arg argflag:0 --devflag
xdoctest -m ubelt.util_arg argflag:0 -df
xdoctest -m ubelt.util_arg argflag:0 --devflag2
xdoctest -m ubelt.util_arg argflag:0 -df2
Example:
>>> # Everyday usage of this function might look like this
>>> import ubelt as ub
>>> # Check if either of these strings are in sys.argv
>>> flag = ub.argflag(('-df', '--devflag'))
>>> if flag:
>>> print(ub.color_text(
>>> 'A hidden developer flag was given!', 'blue'))
>>> print('Pass the hidden CLI flag to see a secret message')
Example:
>>> import ubelt as ub
>>> argv = ['--spam', '--eggs', 'foo']
>>> assert ub.argflag('--eggs', argv=argv) is True
>>> assert ub.argflag('--ans', argv=argv) is False
>>> assert ub.argflag('foo', argv=argv) is True
>>> assert ub.argflag(('bar', '--spam'), argv=argv) is True
"""
if argv is None: # nocover
argv = sys.argv
keys = [key] if isinstance(key, str) else key
flag = any(k in argv for k in keys)
return flag