[Ndn-interest] download a file using PyNDN

[Ishita Dasgupta]

Hi Jeff,

I have a file test.txt being served on my ndnfs server. Prefix:
/ndn/broadcast/ndnfs
I implement SegmentFetcher in the following way and print content and error
message

 name3 = Name(url)
>  dump("Express name ", name3.toUri())
>  interest = Interest(name3)
>  dump(interest.toUri())
>  interest.setInterestLifetimeMilliseconds(1000)
> SegmentFetcher.fetch(face, interest, None, counter.onComplete,
> counter.onError)


This is what i get:

>
> /ndn/broadcast/ndnfs/BigBuckBunny_4s_simple_2014_05_09.mpd?ndn.MustBeFresh=true
> onError
> 2
> Got an unexpected packet without a segment number:
> /ndn/broadcast/ndnfs/BigBuckBunny_4s_simple_2014_05_09.mpd/%C1.FS.file/%FDY%28Q8


When I do an ndndump on the consumer, I see:

> 1495816236.074843 From: 192.1.242.150, To: 192.1.242.151, Tunnel Type:
> TCP, INTEREST:
> /ndn/broadcast/ndnfs/BigBuckBunny_4s_simple_2014_05_09.mpd?ndn.ChildSelector=1&ndn.MustBeFresh=1&ndn.InterestLifetime=1000&ndn.Nonce=3797640908
>



1495816236.085709 From: 192.1.242.151, To: 192.1.242.150, Tunnel Type: TCP,
> DATA:
> /ndn/broadcast/ndnfs/BigBuckBunny_4s_simple_2014_05_09.mpd/%C1.FS.file/%FDY%28Q8


I thought fetching segment number was internally done in your Segment
Fetcher util. Do I need to implement it some way on my end as well?

Regards,
Ishita Dasgupta

*Graduate Student**College of Information and Computer Sciences*
*,UMass Amherst*
*Email*: ishitadg at cs.umass.edu

On Thu, May 25, 2017 at 2:15 PM, Thompson, Jeff <jefft0 at remap.ucla.edu>
wrote:

> Hi Ishita,
>
> We have NDNFS producing sample data at memoria.ndn.ucla.edu. The PyNDN
> code below uses the SegmentFetcher to fetch the segments of a file (a
> JavaScript file). NDNFS has split the file into 12 segments, which
> SegmentFetcher retrieves to supply the content to the callback.
> SegmentFetcher documentation is here:
> https://github.com/named-data/PyNDN2/blob/master/python/
> pyndn/util/segment_fetcher.py#L142
>
> - Jeff T
>
> import time, sys
> from pyndn import Name, Interest, Face
> from pyndn.util import SegmentFetcher
>
> face = Face("memoria.ndn.ucla.edu")
> SegmentFetcher.fetch(face, Interest(Name(
>   "/ndn/edu/ucla/remap/demo/ndn-js-test/named-data.net/wp-
> includes/js/jquery/jquery.js/%FDX%DC5B")),
>   None, lambda content: sys.stdout.write(content.toRawStr()),
>   lambda errorCode, message: sys.stdout.write("Got error " + message))
>
> while True:
>     face.processEvents()
>     time.sleep(0.01)
>
>
> From: Ishita Dasgupta <ishita.dasgupta at gmail.com>
> Date: Thursday, May 25, 2017 at 6:00:00
> To: Jeff Thompson <jefft0 at remap.ucla.edu>, "ndn-interest at lists.cs.ucla.edu"
> <ndn-interest at lists.cs.ucla.edu>
> Subject: Re: [Ndn-interest] download a file using PyNDN
>
> Hi Jeff,
>
> Yes
> ​, the producer is responding to Interests with Data packets representing
> the file. I run NDNFS on the producer.
> ​
>
> On Wed, May 24, 2017 at 4:35 PM Thompson, Jeff <jefft0 at remap.ucla.edu>
> wrote:
>
>> Hi Ishta,
>>
>> In NDN, there is a producer and consumer. The consumer sends an Interest
>> and the producer (or a cache in the network) responds with a Data packet.
>> When you say “an entire file from an NDN server” I assume you mean a
>> producer that is responding to Interests with Data packets representing the
>> file. What producer software is running on the server?
>>
>> - Jeff T
>>
>> From: Ndn-interest <ndn-interest-bounces at lists.cs.ucla.edu> on behalf of
>> Ishita Dasgupta <ishita.dasgupta at gmail.com>
>> Date: Wednesday, May 24, 2017 at 8:29:00
>> To: "ndn-interest at lists.cs.ucla.edu" <ndn-interest at lists.cs.ucla.edu>
>> Subject: [Ndn-interest] download a file using PyNDN
>>
>> Hi All,
>>
>> Has anybody used PyNDN to download an entire file from an ndn server?
>> I see or receive jibberish data in form of one data packet but don't seem
>> to copying the exact content of the file(no matter the size, i.e
>> irrespective of the fact that the file gets divided to multiple segments or
>> just one segment).
>> Any guidance with this would be helpful.
>>
>> Thanks,
>> Ishita
>>
>
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