命令行示例：
基本用法
$ python [file].py hello Kyle Hello, Kyle! $ python [file].py goodbye Kyle Goodbye, Kyle!
W/选项用法（标志）
$ python [file].py hello --greeting=Wazzup Kyle Whazzup, Kyle! $ python [file].py goodbye --greeting=Later Kyle Later, Kyle! $ python [file].py hello --caps Kyle HELLO, KYLE! $ python [file].py hello --greeting=Wazzup --caps Kyle WAZZUP, KYLE!
Argarse：标准库
def greet(args):
output = '{0}, {1}!'.format(args.greeting, args.name)
if args.caps:
output = output.upper()
print(output)
parser = argparse.ArgumentParser()
parser.add_argument('--version', action='version', version='1.0.0')
subparsers = parser.add_subparsers()
hello_parser = subparsers.add_parser('hello')
hello_parser.add_argument('name', help='name of the person to greet')
hello_parser.add_argument('--greeting', default='Hello', help='word to use for the greeting')
hello_parser.add_argument('--caps', action='store_true', help='uppercase the output')
hello_parser.set_defaults(func=greet)
goodbye_parser = subparsers.add_parser('goodbye')
goodbye_parser.add_argument('name', help='name of the person to greet')
goodbye_parser.add_argument('--greeting', default='Hello', help='word to use for the greeting')
goodbye_parser.add_argument('--caps', action='store_true', help='uppercase the output')
goodbye_parser.set_defaults(func=greet)
if __name__ == '__main__':
args = parser.parse_args()
args.func(args)
Docopt
"""usage: greet [--help] <command> [<args>...]
options:
-h --help Show this screen.
--version Show the version.
commands:
hello Say hello
goodbye Say goodbye
"""
from docopt import docopt
from schema import Schema, SchemaError, Optional
HELLO = """usage: basic.py hello [options] [<name>]
-h --help Show this screen.
--caps Uppercase the output.
--greeting=<str> Greeting to use [default: Hello].
"""
GOODBYE = """usage: basic.py goodbye [options] [<name>]
-h --help Show this screen.
--caps Uppercase the output.
--greeting=<str> Greeting to use [default: Goodbye].
"""
def greet(args):
output = '{0}, {1}!'.format(args['--greeting'],
args['<name>'])
if args['--caps']:
output = output.upper()
print(output)
if __name__ == '__main__':
arguments = docopt(__doc__, options_first=True, version='1.0.0')
schema = Schema({
Optional('hello'): bool,
Optional('goodbye'): bool,
'<name>': str,
Optional('--caps'): bool,
Optional('--help'): bool,
Optional('--greeting'): str
})
def validate(args):
try:
args = schema.validate(args)
return args
except SchemaError as e:
exit(e)
if arguments['<command>'] == 'hello':
greet(validate(docopt(HELLO)))
elif arguments['<command>'] == 'goodbye':
greet(validate(docopt(GOODBYE)))
else:
exit("{0} is not a command. See 'options.py --help'.".format(arguments['<command>']))
Click
import click
CONTEXT_SETTINGS = dict(help_option_names=['-h', '--help'])
def greeter(**kwargs):
output = '{0}, {1}!'.format(kwargs['greeting'],
kwargs['name'])
if kwargs['caps']:
output = output.upper()
print(output)
@click.group(context_settings=CONTEXT_SETTINGS)
@click.version_option(version='1.0.0')
def greet():
pass
@greet.command()
@click.argument('name')
@click.option('--greeting', default='Hello', help='word to use for the greeting')
@click.option('--caps', is_flag=True, help='uppercase the output')
def hello(**kwargs):
greeter(**kwargs)
@greet.command()
@click.argument('name')
@click.option('--greeting', default='Goodbye', help='word to use for the greeting')
@click.option('--caps', is_flag=True, help='uppercase the output')
def goodbye(**kwargs):
greeter(**kwargs)
if __name__ == '__main__':
greet()
Invoke
from invoke import task
def greet(name, greeting, caps):
output = '{0}, {1}!'.format(greeting, name)
if caps:
output = output.upper()
print(output)
HELP = {
'name': 'name of the person to greet',
'greeting': 'word to use for the greeting',
'caps': 'uppercase the output'
}
def print_version():
print('1.0.0')
exit(0)
@task(help=HELP)
def hello(name='', greeting='Hello', caps=False, version=False):
"""
Say hello.
"""
if version:
print_version()
greet(name, greeting, caps)
@task(help=HELP)
def goodbye(name='', greeting='Goodbye', caps=False, version=False):
"""
Say goodbye.
"""
if version:
print_version()
greet(name, greeting, caps)
错误处理一般有三种情况：
1、参数不足。
2、无效的选项/标志。
3、需要标志给一个值。
Argparse
$ python argparse/final.py hello
usage: final.py hello [-h] [--greeting GREETING] [--caps] name
final.py hello: error: the following arguments are required: name
$ python argparse/final.py --badoption hello Kyle
usage: final.py [-h] [--version] {hello,goodbye} ...
final.py: error: unrecognized arguments: --badoption
$ python argparse/final.py hello --caps=notanoption Kyle
usage: final.py hello [-h] [--greeting GREETING] [--caps] name
final.py hello: error: argument --caps: ignored explicit argument 'notanoption'
Docopt，需借助于scheme
...
from schema import Schema, SchemaError, Optional
...
schema = Schema({
Optional('hello'): bool,
Optional('goodbye'): bool,
'<name>': str,
Optional('--caps'): bool,
Optional('--help'): bool,
Optional('--greeting'): str
})
def validate(args):
try:
args = schema.validate(args)
return args
except SchemaError as e:
exit(e)
if arguments['<command>'] == 'hello':
greet(validate(docopt(HELLO)))
elif arguments['<command>'] == 'goodbye':
greet(validate(docopt(GOODBYE)))
...
$ python docopt/validation.py hello
None should be instance of <class 'str'>
$ python docopt/validation.py hello --greeting Kyle
None should be instance of <class 'str'>
$ python docopt/validation.py hello --caps=notanoption Kyle
--caps must not have an argument
usage: basic.py hello [options] [<name>]
Click
$ python click/final.py hello Usage: final.py hello [OPTIONS] NAME Error: Missing argument "name". $ python click/final.py hello --badoption Kyle Error: no such option: --badoption $ python click/final.py hello --caps=notanoption Kyle Error: --caps option does not take a value
打包
entry_point本质上是一个到代码单一函数的映射，系统PATH将给出一个命令。entry_point的形式是command = package.module:function
包装click命令
greeter/ ├── greet │ ├── __init__.py │ └── cli.py <-- the same as our final.py └── setup.py
entry_points={
'console_scripts': [
'greet=greet.cli:greet', # command=package.module:function
],
},
当用户安装entry_point创建的包时，setuptools将创建以下可执行脚本（调用greet）并放置它在用户系统的PATH。
#!/usr/bin/python if __name__ == '__main__': import sys from greet.cli import greet sys.exit(greet())
包装Argparse命令
代码：
if __name__ == '__main__': args = parser.parse_args() args.func(args)
变成：
def greet(): args = parser.parse_args() args.func(args) if __name__ == '__main__': greet()
针对entry_point，现在我们可以使用click中定义的相同的模式了。
包装Docopt命令
代码：
if __name__ == '__main__':
arguments = docopt(__doc__, options_first=True, version='1.0.0')
if arguments['<command>'] == 'hello':
greet(docopt(HELLO))
elif arguments['<command>'] == 'goodbye':
greet(docopt(GOODBYE))
else:
exit("{0} is not a command. See 'options.py --help'.".format(arguments['<command>']))
变成：
def greet():
arguments = docopt(__doc__, options_first=True, version='1.0.0')
if arguments['<command>'] == 'hello':
greet(docopt(HELLO))
elif arguments['<command>'] == 'goodbye':
greet(docopt(GOODBYE))
else:
exit("{0} is not a command. See 'options.py --help'.".format(arguments['<command>']))
if __name__ == '__main__':
greet()