Python Advanced Programming Decorator 02

#装饰器02

#参数检查

#主要是用在接收或者返回函数, may be useful when executing in a specific context

#例如: There is a function called by XML-RPC, and Python will not be able to provide its full signature directly as in a static class language, which is required when the XML-RPC customer requires a function signature.

"""

XML-RPC Related learning: Http://zh.wikipedia.org/wiki/XML-RPC

"""

#装饰器能提供这种签名类型 and make sure that the input and output are related to this, as follows

From itertools Import *

rpc_info={}

def xml_rpc (in_= (), out= (Type (None),)):

def _xml_rpc (function):

#注册签名

Func_name=function.func_name

rpc_info[func_name]= (In_,out)

def _check_type (ele,types):

"" "Subfybctuib tgat Cgecjs tge Types" ""

If Len (ele)!=len (types):

Raise TypeError (' argument count is wrong ')

Typed=enumerate (Izip (ele,types))

For index,couple in typed:

Arg,of_right_type=couple

If Isinstance (arg,of_right_type):

Continue

Raise TypeError (' arg #%d should be%s '% (Index,of_right_type))

#封装函数

def __xml_rpcs (*args): #没能允许关键字

#检查输入的内容

Checkable_atrgs=args[1:] #removing Self

_check_type (Checkable_atrgs,in_)

#执行函数

Res=function (*args)

#检查输出内容

If not type (res) in (tuple,list):

Checkable_atrgs= (res,)

Else

Checkable_atrgs=res

_check_type (Checkable_atrgs,out)

#函数及其类型检查成功

return res

Return __xml_rpcs

Return _XML_RPC

#装饰器将该函数注册到全局字符中, and save a list of the types for its parameters and return values, note that LYYNWBIOVWDT is a great simplification,

#例子;

Class R (object):

@xml_rpc (int,int) #two int--none

def meth1 (self,int1=1,int2=1):

print ' received%d and%d '% (INT1,INT2)

@xml_rpc ((str,), (int,)) #string--int

def meth2 (self,phrease):

print ' received%s '% (phrease)

Return 12

Print rpc_info#{' Meth12 ': (<type ' int ';, <type ' int ' >), ' Meth2 ': ((<type ' str;,), (<type ' int ' > ,))}

My1=r ()

My1.meth1 (ON)

My1.meth2 (2)

This example has a problem, if you see a friend, help me to point out, in this first thank you