Re: [PATCHv3 iproute2-next 3/7] iproute_lwtunnel: add options support for erspan metadata

[Xin Long <lucien.xin@gmail.com>]

On Sat, Feb 15, 2020 at 8:21 AM Stephen Hemminger
<stephen@networkplumber.org> wrote:
>
> On Sat, 15 Feb 2020 01:40:27 +0800
> Xin Long <lucien.xin@gmail.com> wrote:
>
> > This's not gonna work. as the output will be:
> > {"ver":"0x2","idx":"0","dir":"0x1","hwid":"0x2"}  (string)
> > instead of
> > {"ver":2,"index":0,"dir":1,"hwid":2} (number)
>
> JSON is typeless. Lots of values are already printed in hex
You may mean JSON data itself is typeless.
But JSON objects are typed when parsing JSON data, which includes
string, number, array, boolean. So it matters how to define the
members' 'type' in JSON data.

For example, in python's 'json' module:

#!/usr/bin/python2
import json
json_data_1 = '{"ver":"0x2","idx":"0","dir":"0x1","hwid":"0x2"}'
json_data_2 = '{"ver":2,"index":0,"dir":1,"hwid":2}'
parsed_json_1 = (json.loads(json_data_1))
parsed_json_2 = (json.loads(json_data_2))
print type(parsed_json_1["hwid"])
print type(parsed_json_2["hwid"])

The output is:
<type 'unicode'>
<type 'int'>

Also, '{"result": true}' is different from '{"result": "true"}' when
loading it in a 3rd-party lib.

I think the JSON data coming from iproute2 is designed to be used by
a 3rd-party lib to parse, not just to show to users. To keep these
members' original type (numbers) is more appropriate, IMO.

Thanks.