DNS¶

resolve: a host name turned into typed addresses.

Import¶

use <net/dns>

The import brings NetError, the channel resolve answers: the module re-exports <net/error>, so a unit that matches on an error writes no second line.

Overview¶

net/dns is a Sushi-source standard-library module: it ships as bundled .sushi source and is merged as a compilation unit when you import it. It is sock_dns_resolve from <net/socket> with parse_ip from <net/ip> over each answer, so a caller is handed IpAddr and never a string it has to read for itself.

An answer the parser cannot read is dropped rather than failing the call, so one unusual family does not lose the usable answers.

Functions¶

`resolve(string host) -> Result@(IpAddr[], NetError)`¶

Resolve a name, or a numeric address, into addresses. A text that is already an address answers with exactly that address and makes no network request.

use <net/dns>
use <net/ip>

fn main() i32:
    match resolve("localhost"):
        Result.Ok(addresses) ->
            foreach(a in addresses.iter()):
                println("{a.text()}")
        Result.Err(_) -> println("no answer")

    return Result.Ok(0)

`resolve_first(string host, bool want_v4) -> Result@(IpAddr, NetError)`¶

The first answer of one family. true asks for IPv4, false for IPv6. When no answer is of that family the error is NetError.InvalidAddress rather than an empty list.

Limitations¶

The order of the answers is the resolver's and is not stable between calls, so do not depend on it. There is no reverse lookup and no SRV.