[atlas] Problems with DNS measurements and NSID

Hi Daniel!

Thanks. Meanwhile I managed to iterate over the JSON list and print the
nsid:

import json
from ripe.atlas.sagan import DnsResult

f=open("dns-from-de-anycast.json","r")
data = f.read()

jdata = json.loads(data)
for d in jdata:
        print d
        result = DnsResult.get(d)
        print(result.responses[0].edns0.options[0].nsid)
        print ""


But the problem is if there was an error during the measurement (eg
timeout), then my script terminates:

{u'from': u'84.132.219.105', u'msm_id': 1666006, u'timestamp':
1400570732, u'fw': 4610, u'proto': u'UDP', u'af': 4, u'msm_name':
u'Tdig', u'prb_id': 2960, u'error': {u'timeout': 5000}, u'src_addr':
u'192.168.179.20', u'group_id': 1666005, u'type': u'dns', u'dst_addr':
u'194.0.25.16'}
Traceback (most recent call last):
  File "json-file.py", line 11, in <module>
    print(result.responses[0].edns0.options[0].nsid)
IndexError: list index out of range


What is the suggested way to find out if a result is valid and exists?

Thanks
Klaus


On 20.05.2014 17:47, Daniel Quinn wrote:
> On Tue 20 May 2014 17:08:47 CEST, Klaus Darilion wrote:
> 
>     Hi Daniel!
> 
> Hi!
> 
>     Actually I tried it today but failed obviously due to my lack of Python.
>     It would be great if you could add an example to the README e.g. with
>     full result parsing:
> 
>       * load the json file from disk
>       * loop over every result (json list)
>       * print some value
> 
> The full documentation already has a few examples
> <https://atlas.ripe.net/docs/sagan/#examples> that should be enough to
> get you going (I’ve just added some more), but here’s a breakdown of
> what you’re wanting:
> 
> |from ripe.atlas.sagan import Result
> 
> my_results_file = "/path/to/file.txt"
> with open(my_results_file) as results:
>     for result in results.readlines():
>         parsed_result = Result.get(result)
>         print(parsed_result.origin)
> |
> 
> Once you have a |parsed_result|, you have access to all of the
> properties of that result, which are defined in the full documentation
> <https://atlas.ripe.net/docs/sagan/#attributes-methods>.
> 
>     Why do I have to use the responses[0] object? Can there be multiple
>     responses with different nsids?
> 
> In some cases, DNS results /can/ contain multiple responses. In an
> effort to maintain consistency for all DNS results, we opted to treat
> all DNS results as if they contain a list of responses — even if that
> list is of only one response. This makes it easier to write scripts that
> make use of the object, since you always have a consistent data type in
> |parsed_result.responses|.
> 
> I hope that helps!
>