Crate c_ares_resolver

DNS resolvers built on c-ares, for asynchronous DNS requests.

This crate provides three resolver types - the Resolver, the FutureResolver, and the BlockingResolver:

• The Resolver is the thinnest wrapper around the underlying c-ares library. It returns answers via callbacks. The other resolvers are built on top of this.

• The FutureResolver returns answers as std::future::Futures.

• The BlockingResolver isn’t asynchronous at all - as the name suggests, it blocks until the lookup completes.

On all resolvers:

• methods like query_xxx correspond to the c-ares function ares_query, which “initiates a single-question DNS query”.

• methods like search_xxx correspond to the c-ares function ares_search, which “initiates a series of single-question DNS queries … using the channel’s search domains as well as a host alias file given by the HOSTALIAS environment variable”.

See c-ares documentation for more details.

Example

extern crate c_ares_resolver;
extern crate futures_executor;
use futures_executor::block_on;

fn main() {
    let resolver = c_ares_resolver::FutureResolver::new().unwrap();
    let query = resolver.query_a("google.com");
    let response = block_on(query);
    match response {
        Ok(result) => println!("{}", result),
        Err(e) => println!("Lookup failed with error '{}'", e)
    }
}

Further examples showing how to use the library can be found here.

Structs

• BlockingResolver
  A blocking DNS resolver.
• CAresFuture
  The type of future returned by methods on the FutureResolver.
• FutureResolver
  An asynchronous DNS resolver, which returns results as futures::Futures.
• HostResults
  An owned version of c_ares::HostResults.
• NameInfoResult
  An owned version of c_ares::NameInfoResult.
• Options
  Used to configure the behaviour of the resolver.
• Resolver
  An asynchronous DNS resolver, which returns results via callbacks.

Enums

• Error
  Error codes that the library might return.