I'm trying to write a (very) primitive "service discovery" module, and it seems
"nativesockets.Hostent.addrList" is not what I would have expected.
Here the code I used:
import nativesockets
import net
import strutils
proc parseURL(hostport: string): tuple[ip: string, port: Port, url: string]
=
let idx = hostport.find(':')
if (idx < 1) or (idx == high(hostport)):
raise newException(Exception, "Bad URL: '" & hostport & "': port
missing")
let host = hostport.substr(0,idx-1)
let portstr = hostport.substr(idx+1)
var port = -1
try:
port = parseInt(portstr)
except:
discard
if (port < 1) or (port > 65535):
raise newException(Exception, "Bad URL: '" & hostport & "': bad port")
var ip: IpAddress
if isIpAddress(host):
try:
ip = parseIpAddress(host)
except:
raise newException(Exception, "Bad URL: '" & hostport & "': bad IP
address")
else:
var hostent: Hostent
try:
hostent = getHostByName(host)
except:
raise newException(Exception, "Bad URL: '" & hostport & "': bad
hostname")
if hostent.addrList.len == 0:
raise newException(Exception, "Bad URL: '" & hostport & "': no IP for
hostname")
let a = hostent.addrList[0]
try:
ip = parseIpAddress(a)
except:
raise newException(Exception, "Bad URL: '" & hostport & "': failed to
parse IP of address: " & $len(a) & " " & a)
result = ($ip, Port(port), hostport)
echo("RESULT: " & $parseURL("google.com:80"))
This fails with the last "raise" line, like this:
testgethostbyname.nim(40) testgethostbyname
testgethostbyname.nim(37) parseURL
Error: unhandled exception: Bad URL: 'google.com:80': failed to parse IP of
address: 14 Ï:ð.google.com [Exception]
Error: execution of an external program failed: '../bin/testgethostbyname '
Either there is something terribly wrong with my code, or "hostent.addrList[0]"
is not something like "1.2.3.4", but something else entirely. In that case,
since the type is "string", how am I meant to "interpret" it, to get something
like "1.2.3.4"? Or is there an alternative call to getHostByName() that
actually returns an IP in a "usable format"?
I wanted to use the "ip" to pass it to Socket.connect(ip, port), so I save the
DNS query on repeated calls.
