Net-SNMP: Issue 129

[ashraful-islam]

As part of this issue/initiate: markabrahams/node-net-snmp#129
I have decided to re-create the library in typescript entirely.

Also, except introducing the chai(for assert) I didn't change the tests entirely.
Every test appears to pass as is.

Please review at your leisure and leave some feedbacks :)

[markabrahams]

Thanks for this @ashraful-islam - that's quite a refactor! :-)

A couple of initial thoughts on this:

(1) I think it would be best to maintain the same export structure for backwards compatibility (even though it's a bit weird doubling up Reader and Writer at two different levels). The current structure is:

{
    Ber: { <the export you have now> }
    BerReader: Reader,
    BerWriter: Writer
}

(2) The node-net-snmp library needs to work against this, and my initial tests suggest that the community-based message parsing works OK with this new code, and noAuthNoPriv v3 also works. However, authNoPriv and authPriv v3 give an error message:
ResponseInvalidError: Wrong Digest (incorrect password, community or key)
so this needs to be fixed.

[ashraful-islam]

@markabrahams Hey, thanks for taking the time to look into it.

So, my todo for now is:

• fix the export to maintain backward compatibility
• check this PR w/ net-snmp to debug the authNoPriv & authPriv(v3) issues.

I will update this branch with these changes and fix for the second point soon. 😃