问题
I'd like to load arguments and options from a database. I am allowing users to define their own options and arguments. Users can call a remote api on the command line. They specify the URL and parameters to the end point. Here is what the data from database looks like
[
{
"name": "thename1",
"short": "a",
"long": "ace"
"type": "string",
"required": false
},
{
"name": "thename2",
"short": "b",
"long": "bravo"
"type": "number",
"required": true
},
{
"name": "thename3",
"short": "c",
"long": "candy"
"type": "array",
"required": true
}
]
These parameters align with what the remote end point needs. Each API endpoint has different parameters hence the reason they need to be dynamic. Here is how the command line will look.
command run www.mysite.com/api/get -a testparam --bravo testpara2 -c item1 item2
The param and value will be mapped in a URL. Is there a way to setup dynamic parameters in click?
回答1:
This can be done by building a custom decorator that calls the click.option decorator multiple times after translating the given data structure into click equivalents.
Code:
import click
def options_from_db(options):
map_to_types = dict(
array=str,
number=float,
string=str,
)
def decorator(f):
for opt_params in reversed(options):
param_decls = (
'-' + opt_params['short'],
'--' + opt_params['long'],
opt_params['name'])
attrs = dict(
required=opt_params['required'],
type=map_to_types.get(
opt_params['type'], opt_params['type'])
)
if opt_params['type'] == 'array':
attrs['cls'] = OptionEatAll
attrs['nargs'] = -1
click.option(*param_decls, **attrs)(f)
return f
return decorator
Using the options_from_db decorator:
To use the new decorator, decorate the command, and pass the option data from the db like:
@options_from_db(run_options)
def command(*args, **kwargs):
....
How does this work?
The @click.option() decorator is, like all decorators, a function. In this case it annotates the decorated function, and returns the same function. So we can simply call it multiple times to annotate our decorated function.
Note: your array parameter violates the click requirement to not allow nargs < 0 on options. But there is another answer that enables this, and this answer uses the code from there.
Code from other answer:
class OptionEatAll(click.Option):
def __init__(self, *args, **kwargs):
self.save_other_options = kwargs.pop('save_other_options', True)
nargs = kwargs.pop('nargs', -1)
assert nargs == -1, 'nargs, if set, must be -1 not {}'.format(nargs)
super(OptionEatAll, self).__init__(*args, **kwargs)
self._previous_parser_process = None
self._eat_all_parser = None
def add_to_parser(self, parser, ctx):
def parser_process(value, state):
# method to hook to the parser.process
done = False
value = [value]
if self.save_other_options:
# grab everything up to the next option
while state.rargs and not done:
for prefix in self._eat_all_parser.prefixes:
if state.rargs[0].startswith(prefix):
done = True
if not done:
value.append(state.rargs.pop(0))
else:
# grab everything remaining
value += state.rargs
state.rargs[:] = []
value = tuple(value)
# call the actual process
self._previous_parser_process(value, state)
retval = super(OptionEatAll, self).add_to_parser(parser, ctx)
for name in self.opts:
our_parser = parser._long_opt.get(
name) or parser._short_opt.get(name)
if our_parser:
self._eat_all_parser = our_parser
self._previous_parser_process = our_parser.process
our_parser.process = parser_process
break
return retval
Test Code:
run_options = [
{
"name": "thename1",
"short": "a",
"long": "ace",
"type": "string",
"required": False
}, {
"name": "thename2",
"short": "b",
"long": "bravo",
"type": "number",
"required": True
}, {
"name": "thename3",
"short": "c",
"long": "candy",
"type": "array",
"required": True
}
]
@click.group()
def cli():
pass
@cli.command()
@options_from_db(run_options)
@click.argument('url')
def run(*args, **kwargs):
click.echo('args: {}'.format(args) )
click.echo('kwargs: {}'.format(kwargs))
if __name__ == "__main__":
commands = (
'run www.mysite.com/api/get -a testparam --bravo 5 -c item1 item2',
'',
'--help',
'run --help',
)
import sys, time
time.sleep(1)
print('Click Version: {}'.format(click.__version__))
print('Python Version: {}'.format(sys.version))
for cmd in commands:
try:
time.sleep(0.1)
print('-----------')
print('> ' + cmd)
time.sleep(0.1)
cli(cmd.split())
except BaseException as exc:
if str(exc) != '0' and \
not isinstance(exc, (click.ClickException, SystemExit)):
raise
Results:
Click Version: 6.7
Python Version: 3.6.3 (v3.6.3:2c5fed8, Oct 3 2017, 18:11:49) [MSC v.1900 64 bit (AMD64)]
-----------
> run www.mysite.com/api/get -a testparam --bravo 5 -c item1 item2
args: ()
kwargs: {'thename1': 'testparam', 'thename2': 5.0, 'thename3': ('item1', 'item2'), 'url': 'www.mysite.com/api/get'}
-----------
>
Usage: test.py [OPTIONS] COMMAND [ARGS]...
Options:
--help Show this message and exit.
Commands:
run
-----------
> --help
Usage: test.py [OPTIONS] COMMAND [ARGS]...
Options:
--help Show this message and exit.
Commands:
run
-----------
> run --help
Usage: test.py run [OPTIONS] URL
Options:
-a, --ace TEXT
-b, --bravo FLOAT [required]
-c, --candy TEXT [required]
--help Show this message and exit.
来源：https://stackoverflow.com/questions/50499340/specify-options-and-arguments-dynamically