用原生的參數(shù)解析工具非常繁瑣，而click工具入手就非常簡(jiǎn)單了，而且直觀。建立以下這個(gè)程序a.py[1], cli會(huì)有子命令make，make有選項(xiàng)--work：
1 import click
2
3 @click.group()
4 def cli():
5 print("cli")
6
7 @cli.command()
8 @click.option('--work', default=None)
9 def make(work):
10 print(type(work))
11 print(work)
12
13 if __name__ == '__main__':
14 cli()
a.py在bash下執(zhí)行：
$ python a.py
Usage: a.py [OPTIONS] COMMAND [ARGS]...
Options:
--help Show this message and exit.
Commands:
make
在bash下執(zhí)行:
$ python a.py make
cli
<type 'NoneType'>
None
a.py在bash下執(zhí)行：
$ python a.py make --work='我'
cli
<type 'unicode'>
我
a.py修改, 增加make的參數(shù)name:
7 @cli.command()
8 @click.option('--work', default=None)
9 @click.argument('name')
10 def make(work, name):
11 print(u'work: {}, type: {}'.format(work, type(work)))
12 print(u'name: {}'.format(name))
在bash下執(zhí)行：
$ python a.py make --work='我'
cli
Usage: a.py make [OPTIONS] NAME
Try "a.py make --help" for help.
Error: Missing argument "NAME".
注意執(zhí)行時(shí)提示：Error: Missing argument "NAME"。 表示需要參數(shù)NAME。我們重新執(zhí)行：
$ python a.py make --work='我' '張三'
cli
work: 我, type: <type 'unicode'>
name: 張三
可以用click.Choice限定參數(shù)或者選項(xiàng)的取值范圍，修改代碼：
7 @cli.command()
8 @click.option('--work', default=None, type=click.Choice(['全職', '兼職']))
9 @click.argument('name')
10 def make(work, name):
11 print(u'work: {}, type: {}'.format(work, type(work)))
12 print(u'name: {}'.format(name))
我們重新執(zhí)行：
$ python a.py make --work='全' '張三'
cli
/home/jzhou/env/wf/lib/python2.7/site-packages/click/types.py:156: UnicodeWarning: Unicode equal comparison failed to convert both arguments to Unicode - interpreting them as being unequal
if value in self.choices:
/home/jzhou/env/wf/lib/python2.7/site-packages/click/types.py:176: UnicodeWarning: Unicode equal comparison failed to convert both arguments to Unicode - interpreting them as being unequal
if normed_value in normed_choices:
Traceback (most recent call last):
File "a.py", line 16, in <module>
cli()
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/core.py", line 764, in __call__
return self.main(*args, **kwargs)
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/core.py", line 717, in main
rv = self.invoke(ctx)
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/core.py", line 1135, in invoke
sub_ctx = cmd.make_context(cmd_name, args, parent=ctx)
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/core.py", line 641, in make_context
self.parse_args(ctx, args)
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/core.py", line 940, in parse_args
value, args = param.handle_parse_result(ctx, opts, args)
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/core.py", line 1469, in handle_parse_result
value = self.full_process_value(ctx, value)
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/core.py", line 1790, in full_process_value
return Parameter.full_process_value(self, ctx, value)
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/core.py", line 1438, in full_process_value
value = self.process_value(ctx, value)
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/core.py", line 1428, in process_value
return self.type_cast_value(ctx, value)
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/core.py", line 1417, in type_cast_value
return _convert(value, (self.nargs != 1) + bool(self.multiple))
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/core.py", line 1415, in _convert
return self.type(value, self, ctx)
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/types.py", line 39, in __call__
return self.convert(value, param, ctx)
File "/home/jzhou/env/wf/lib/python2.7/site-packages/click/types.py", line 180, in convert
(value, ', '.join(self.choices)), param, ctx)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe5 in position 16: ordinal not in range(128)
這個(gè)是因?yàn)閏lick在python 2環(huán)境下沒有考慮把參數(shù)或者選項(xiàng)轉(zhuǎn)化為unicode，下載click_patch[2], clone后在目錄下安裝：
$ git clone https://github.com/fininfotech/click_patch.git
Cloning into 'click_patch'...
remote: Enumerating objects: 11, done.
remote: Counting objects: 100% (11/11), done.
remote: Compressing objects: 100% (8/8), done.
remote: Total 11 (delta 1), reused 8 (delta 1), pack-reused 0
Unpacking objects: 100% (11/11), done.
$ cd click_patch
$ python setup.py install
running install
....
修改a.py:
1 # -*- coding:utf-8 -*-
2 import click
3 import click_patch
4
5 @click.group()
6 def cli():
7 print("cli")
8
9 @cli.command()
10 @click.option('--work', default=None, type=click.Choice([u'全職', u'兼職']))
11 @click.argument('name')
12 def make(work, name):
13 print(u'work: {}, type: {}'.format(work, type(work)))
14 print(u'name: {}'.format(name))
15
16 if __name__ == '__main__':
17 cli()
繼續(xù)執(zhí)行：
$ python a.py make --work='全' '張三'
cli
Usage: a.py make [OPTIONS] NAME
Try "a.py make --help" for help.
Error: Invalid value for "--work": invalid choice: 全. (choose from 全職, 兼職)
$ python a.py make --work='全職' '張三'
cli
work: 全職, type: <type 'unicode'>
name: 張三
總的來說，click用來做命令行工具非常方便，但是在python 2.7環(huán)境下還存在一些字符編碼上的問題，可以使用click_patch來改正。
