Struct hickory_resolver::Resolver

pub struct Resolver { /* private fields */ }

Available on crate feature tokio-runtime only.

The Resolver is used for performing DNS queries.

For forward (A) lookups, hostname -> IP address, see: Resolver::lookup_ip

Special note about resource consumption. The Resolver and all Hickory DNS software is built around the Tokio async-io library. This synchronous Resolver is intended to be a simpler wrapper for of the AsyncResolver. To allow the Resolver to be Send + Sync, the construction of the AsyncResolver is lazy, this means some of the features of the AsyncResolver, like performance based resolution via the most efficient NameServer will be lost (the lookup cache is shared across invocations of the Resolver). If these other features of the Hickory DNS Resolver are desired, please use the tokio based AsyncResolver.

Note: Threaded/Sync usage: In multithreaded scenarios, the internal Tokio Runtime will block on an internal Mutex for the tokio Runtime in use. For higher performance, it’s recommended to use the AsyncResolver.

Implementations

impl Resolver

pub fn new(config: ResolverConfig, options: ResolverOpts) -> Result<Self>

Constructs a new Resolver with the specified configuration.

Arguments

• config - configuration for the resolver
• options - resolver options for performing lookups

Returns

A new Resolver or an error if there was an error with the configuration.

pub fn default() -> Result<Self>

Constructs a new Resolver with default config and default options.

See ResolverConfig::default and ResolverOpts::default for more information.

Returns

A new Resolver or an error if there was an error with the configuration.

pub fn from_system_conf() -> Result<Self>

Available on crate feature system-config and (Unix or Windows) only.

Constructs a new Resolver with the system configuration.

This will use /etc/resolv.conf on Unix OSes and the registry on Windows.

pub fn clear_cache(&self)

Flushes/Removes all entries from the cache

pub fn config(&self) -> &ResolverConfig

Read the config for this resolver.

pub fn options(&self) -> &ResolverOpts

Read the options for this resolver.

pub fn lookup<N: IntoName>( &self, name: N, record_type: RecordType, ) -> ResolveResult<Lookup>

Generic lookup for any RecordType

WARNING This interface may change in the future, please use Self::lookup_ip or another variant for more stable interfaces.

Arguments

• name - name of the record to lookup, if name is not a valid domain name, an error will be returned
• record_type - type of record to lookup

pub fn lookup_ip<N: IntoName + TryParseIp>( &self, host: N, ) -> ResolveResult<LookupIp>

Performs a dual-stack DNS lookup for the IP for the given hostname.

See the configuration and options parameters for controlling the way in which A(Ipv4) and AAAA(Ipv6) lookups will be performed. For the least expensive query a fully-qualified-domain-name, FQDN, which ends in a final ., e.g. www.example.com., will only issue one query. Anything else will always incur the cost of querying the ResolverConfig::domain and ResolverConfig::search.

Arguments

• host - string hostname, if this is an invalid hostname, an error will be returned.

pub fn reverse_lookup(&self, query: IpAddr) -> ResolveResult<ReverseLookup>

Performs a lookup for the associated type.

Arguments

• query - a type which can be converted to Name via From.

pub fn ipv4_lookup<N: IntoName>(&self, query: N) -> ResolveResult<Ipv4Lookup>

Performs a lookup for the associated type.

hint queries that end with a ‘.’ are fully qualified names and are cheaper lookups

Arguments

• query - a &str which parses to a domain name, failure to parse will return an error

pub fn ipv6_lookup<N: IntoName>(&self, query: N) -> ResolveResult<Ipv6Lookup>

Performs a lookup for the associated type.

hint queries that end with a ‘.’ are fully qualified names and are cheaper lookups

Arguments

• query - a &str which parses to a domain name, failure to parse will return an error

pub fn mx_lookup<N: IntoName>(&self, query: N) -> ResolveResult<MxLookup>

Performs a lookup for the associated type.

hint queries that end with a ‘.’ are fully qualified names and are cheaper lookups

Arguments

• query - a &str which parses to a domain name, failure to parse will return an error

pub fn ns_lookup<N: IntoName>(&self, query: N) -> ResolveResult<NsLookup>

Performs a lookup for the associated type.

hint queries that end with a ‘.’ are fully qualified names and are cheaper lookups

Arguments

• query - a &str which parses to a domain name, failure to parse will return an error

pub fn soa_lookup<N: IntoName>(&self, query: N) -> ResolveResult<SoaLookup>

Performs a lookup for the associated type.

hint queries that end with a ‘.’ are fully qualified names and are cheaper lookups

Arguments

• query - a &str which parses to a domain name, failure to parse will return an error

pub fn srv_lookup<N: IntoName>(&self, query: N) -> ResolveResult<SrvLookup>

Performs a lookup for the associated type.

hint queries that end with a ‘.’ are fully qualified names and are cheaper lookups

Arguments

• query - a &str which parses to a domain name, failure to parse will return an error

pub fn tlsa_lookup<N: IntoName>(&self, query: N) -> ResolveResult<TlsaLookup>

Performs a lookup for the associated type.

hint queries that end with a ‘.’ are fully qualified names and are cheaper lookups

Arguments

• query - a &str which parses to a domain name, failure to parse will return an error

pub fn txt_lookup<N: IntoName>(&self, query: N) -> ResolveResult<TxtLookup>

Performs a lookup for the associated type.

hint queries that end with a ‘.’ are fully qualified names and are cheaper lookups

Arguments

• query - a &str which parses to a domain name, failure to parse will return an error