About size of Unicode string

[Frank Abel Cancio Bello]

Hi all!

I need know the size of string object independently of its encoding. For
example:

len('123') == len('123'.encode('utf_8'))

while the size of '123' object is different of the size of
'123'.encode('utf_8')

More:
I need send in HTTP request a string. Then I need know the length of the
string to set the header "content-length" independently of its encoding.

Any idea?

Thanks in advance
Frank