NIS /local/chain/blocks-after unauthorized [SOLVED]

Technical Discussion
#1

Hey guys

While I’m working on a block explorer, I’ve experienced an issue using the POST call /local/chain/blocks-after.

Every node I’ve tried so far, gives me back the following response:

{
    "timeStamp": 96922943,
    "error": "Unauthorized",
    "message": "remote *.*.*.* attempted to call local /local/chain/blocks-after",
    "status": 401
}

I tried this one http://hugealice.nem.ninja:7890/local/chain/blocks-after and even set up my very own supernode. The logs entry after I perform the request:

2018-04-23 19:18:00.544 WARNING remote *.*.*.* attempted to call local /local/chain/blocks-after (org.nem.nis.controller.te.woe preHandle)
2018-04-23 19:18:00.545 INFO Http Status Code 401: remote*.*.*.* attempted to call local /local/chain/blocks-after (org.nem.core.connect.ErrorResponse <init>)

Any help would be appreciated.

Thanks!

#2

This is local API. You can call it only on local NIS.

#3

Hey mate

thanks for the fast reply. Well okay. It would have been quite a convenient function because it gives me the blocks including the hashes back.

So I’ve done some research on it and found this post regarding hashing a block: Hash of the latest block via the NIS API

But still, I somehow don’t get it. Is anybody out there able to provide me either a more detailed description or maybe even a code snippet on how I can accomplish that?

thanks!

#4

I guess the block explorer is coded in javascript?
You could probably use nem-sdk or nem-api libraries to hash the block? I have not worked with the nem libraries so far but they should make life easier for you.

1 Like
#5

yep, it’s javascript.

I checked some libraries but found nothing which could help me. I checked the github repo of this explorer: http://explorer.nemchina.com/

and it seems they use the above mentioned api call. Is there a reason the request is only available on a local nis?

#6

Okay, I just found the solution (at least for my case). In the nis-ncc config the following section allows me to set trusted hosts and ip’s:

# List of trusted IP addresses (pipe-separated). Requests from these addresses are treated as local requests.
# NIS usually checks if a request comes from the local machine and if not, certain requests get rejected
# (requests involving the private key). These requests will not get rejected, if they come from an IP in this list.
# valid forms are:
# fully qualified ip: 127.0.0.1, 0:0:0:0:0:0:0:1
# host name: bob.nem.ninja
# partial wildcard ip: 127.0.0.*, 0:0:0:0:0:0:0:*
nis.additionalLocalIps =

so this is it then =)

#7

That works if you run your own NIS and do the query from a non-local client.

1 Like
#8

correct. but that’s sufficient for my case. Would be still interested though on how the block hashing works. anyway, I’m happy that I can go on now. thanks for your support!

#9