Examples? about asynctools HOT 4 CLOSED

This Port argument was added to stay compatible with synchronous getAddrInfo procedure declared here:
https://github.com/nim-lang/Nim/blob/devel/lib/pure/nativesockets.nim#L222

This Port is not used in DNS request actually, but used to form up result array of returned addresses. If you don't care about, or don't know, please use Port(0).

This is simple example for server side:

var server_socket = create_server_socket()

var aiList = getAddrInfo("0.0.0.0", Port(13337))
if bindAddr(server_socket, aiList.ai_addr,
            aiList.ai_addrlen.Socklen) < 0'i32:
  freeAddrInfo(aiList)
  raiseOSError(osLastError())

As you can see you can easily pass aiList to bindAddr and your server will setup on 0.0.0.0:13337.

from asynctools.

Compilation error, you mentioned got fixed.

from asynctools.

Hi, thank you very much for the quick response! I have managed to get it working, but I can't make the jump from Python's asyncio to Nim in my head. Sorry for being thick here! I was wondering if you would be willing to help. I have a very simple example of what I am trying to do in some pseudo-code that isn't working:

import asyncdispatch
import asynctools/asyncdns


proc lookup(n: string) {.async.} =
  return await asyncGetAddrInfo(n, Port(0))

proc callback(f: Future) =
   echo("$1 resolved to ip $2".format(f.domain, f.ip))

proc main() {.async.} =
  let domains = @["www.google.ca", "www.microsoft.com", "www.apple.com"]
  var answers = @[]

  for domain in domains:
    lookup(domain)
    # add callback?

waitFor main()

I have Googled around quite a bit and I can't seem to figure it out. Again, thanks so much!

from asynctools.

For anyone else that has the same questions as me I'll continue this thread. This code works but doesn't do exactly what I want:
edit: updated code

import asyncdispatch, typetraits, nativesockets
import asynctools/asyncdns


type
  DNSQueryResult = ref object
    name: string
    error: bool
    ans: ptr AsyncAddrInfo

proc lookup(n: string): Future[DNSQueryResult] {.async.} =
  var response = await asyncGetAddrInfo(n, Port(0))
  return DNSQueryResult(name:n, error:false, ans:response)

proc main() {.async.} =
  let domains = @["www.google.ca", "www.microsoft.com", "www.apple.com"]
  var futures = newSeq[Future[DNSQueryResult]]()
  for domain in domains:
    futures.add(lookup(domain))
  let results = await all futures
  for r in results:
    echo(r.name)
    echo(r.ans)
    echo()

waitFor main()

I'd like to be able to handle each response in a callback. Also, I don't know what the best way to get the IP address from the answer is. Still researching...

from asynctools.