Crate async_std_resolver
source · [−]Expand description
The Resolver is responsible for performing recursive queries to lookup domain names.
This is a 100% in process DNS resolver. It does not use the Host OS’ resolver. If what is desired is to use the Host OS’ resolver, generally in the system’s libc, then the std::net::ToSocketAddrs
variant over &str
should be used.
Unlike the trust-dns-client
, this tries to provide a simpler interface to perform DNS queries. For update options, i.e. Dynamic DNS, the trust-dns-client
crate must be used instead. The Resolver library is capable of searching multiple domains (this can be disabled by using an FQDN during lookup), dual-stack IPv4/IPv6 lookups, performing chained CNAME lookups, and features connection metric tracking for attempting to pick the best upstream DNS resolver.
Use AsyncResolver
for performing DNS queries. AsyncResolver
is a async-std
based async resolver, and can be used inside any asyn-std
based system.
This as best as possible attempts to abide by the DNS RFCs, please file issues at https://github.com/bluejekyll/trust-dns .
Usage
Declare dependency
[dependency]
async-std-resolver = "*"
Using the async-std Resolver
For more advanced asynchronous usage, the AsyncResolver
is integrated with async-std.
use std::net::*;
use async_std::prelude::*;
use async_std_resolver::{resolver, config};
#[async_std::main]
async fn main() {
// Construct a new Resolver with default configuration options
let resolver = resolver(
config::ResolverConfig::default(),
config::ResolverOpts::default(),
).await.expect("failed to connect resolver");
// Lookup the IP addresses associated with a name.
// This returns a future that will lookup the IP addresses, it must be run in the Core to
// to get the actual result.
let mut response = resolver.lookup_ip("www.example.com.").await.unwrap();
// There can be many addresses associated with the name,
// this can return IPv4 and/or IPv6 addresses
let address = response.iter().next().expect("no addresses returned!");
if address.is_ipv4() {
assert_eq!(address, IpAddr::V4(Ipv4Addr::new(93, 184, 216, 34)));
} else {
assert_eq!(address, IpAddr::V6(Ipv6Addr::new(0x2606, 0x2800, 0x220, 0x1, 0x248, 0x1893, 0x25c8, 0x1946)));
}
}
Using the host system config
On Unix systems, the /etc/resolv.conf
can be used for configuration. Not all options specified in the host systems resolv.conf
are applicable or compatible with this software. In addition there may be additional options supported which the host system does not. Example:
use std::net::*;
use async_std::prelude::*;
use async_std_resolver::{resolver_from_system_conf, config};
#[async_std::main]
async fn main() {
// Use the host OS'es `/etc/resolv.conf`
let resolver = resolver_from_system_conf().await.unwrap();
let response = resolver.lookup_ip("www.example.com.").await.unwrap();
}
Re-exports
pub use trust_dns_resolver::proto;
Modules
Configuration for a resolver
Lookup result from a resolution of ipv4 and ipv6 records with a Resolver.
LookupIp result from a resolution of ipv4 and ipv6 records with a Resolver.
Structs
The error type for errors that get returned in the crate
Functions
Construct a new async-std based AsyncResolver
with the provided configuration.
Constructs a new async-std based Resolver with the system configuration.
Type Definitions
AsyncStd default connection
AsyncStd default connection provider
An AsyncResolver used with async_std