io.netty.resolver.dns

Class DnsNameResolver

java.lang.Object

io.netty.resolver.SimpleNameResolver<InetAddress>

io.netty.resolver.InetNameResolver

io.netty.resolver.dns.DnsNameResolver

All Implemented Interfaces:

NameResolver<InetAddress>, Closeable, AutoCloseable

@UnstableApi
public class DnsNameResolver
extends InetNameResolver

A DNS-based InetNameResolver.

Constructor Summary

Constructors

Constructor and Description

DnsNameResolver(EventLoop eventLoop, ChannelFactory<? extends DatagramChannel> channelFactory, DnsCache resolveCache, DnsCache authoritativeDnsServerCache, DnsQueryLifecycleObserverFactory dnsQueryLifecycleObserverFactory, long queryTimeoutMillis, ResolvedAddressTypes resolvedAddressTypes, boolean recursionDesired, int maxQueriesPerResolve, boolean traceEnabled, int maxPayloadSize, boolean optResourceEnabled, HostsFileEntriesResolver hostsFileEntriesResolver, DnsServerAddressStreamProvider dnsServerAddressStreamProvider, String[] searchDomains, int ndots, boolean decodeIdn) Creates a new DNS-based name resolver that communicates with the specified list of DNS servers.

Method Summary

Modifier and Type	Method and Description
DnsCache	authoritativeDnsServerCache() Returns the cache used for authoritative DNS servers for a domain.
void	close() Closes the internal datagram channel used for sending and receiving DNS messages, and clears all DNS resource records from the cache.
protected void	doResolve(String inetHost, DnsRecord[] additionals, Promise<InetAddress> promise, DnsCache resolveCache) Hook designed for extensibility so one can pass a different cache on each resolution attempt instead of using the global one.
protected void	doResolve(String inetHost, Promise<InetAddress> promise) Invoked by SimpleNameResolver.resolve(String) to perform the actual name resolution.
protected void	doResolveAll(String inetHost, DnsRecord[] additionals, Promise<List<InetAddress>> promise, DnsCache resolveCache) Hook designed for extensibility so one can pass a different cache on each resolution attempt instead of using the global one.
protected void	doResolveAll(String inetHost, Promise<List<InetAddress>> promise) Invoked by SimpleNameResolver.resolveAll(String) to perform the actual name resolution.
protected EventLoop	executor() Returns the EventExecutor which is used to notify the listeners of the Future returned by SimpleNameResolver.resolve(String).
HostsFileEntriesResolver	hostsFileEntriesResolver() Returns the component that tries to resolve hostnames against the hosts file prior to asking to remotes DNS servers.
boolean	isOptResourceEnabled() Returns the automatic inclusion of a optional records that tries to give the remote DNS server a hint about how much data the resolver can read per response is enabled.
boolean	isRecursionDesired() Returns true if and only if this resolver sends a DNS query with the RD (recursion desired) flag set.
boolean	isTraceEnabled() Returns if this resolver should generate the detailed trace information in an exception message so that it is easier to understand the cause of resolution failure.
int	maxPayloadSize() Returns the capacity of the datagram packet buffer (in bytes).
int	maxQueriesPerResolve() Returns the maximum allowed number of DNS queries to send when resolving a host name.
Future<AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(DnsQuestion question) Sends a DNS query with the specified question.
Future<AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(DnsQuestion question, Iterable<DnsRecord> additionals) Sends a DNS query with the specified question with additional records.
Future<AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(DnsQuestion question, Promise<AddressedEnvelope<? extends DnsResponse,InetSocketAddress>> promise) Sends a DNS query with the specified question.
Future<AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(InetSocketAddress nameServerAddr, DnsQuestion question) Sends a DNS query with the specified question using the specified name server list.
Future<AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(InetSocketAddress nameServerAddr, DnsQuestion question, Iterable<DnsRecord> additionals) Sends a DNS query with the specified question with additional records using the specified name server list.
Future<AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(InetSocketAddress nameServerAddr, DnsQuestion question, Iterable<DnsRecord> additionals, Promise<AddressedEnvelope<? extends DnsResponse,InetSocketAddress>> promise) Sends a DNS query with the specified question with additional records using the specified name server list.
Future<AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(InetSocketAddress nameServerAddr, DnsQuestion question, Promise<AddressedEnvelope<? extends DnsResponse,InetSocketAddress>> promise) Sends a DNS query with the specified question using the specified name server list.
long	queryTimeoutMillis() Returns the timeout of each DNS query performed by this resolver (in milliseconds).
Future<InetAddress>	resolve(String inetHost, Iterable<DnsRecord> additionals) Resolves the specified name into an address.
Future<InetAddress>	resolve(String inetHost, Iterable<DnsRecord> additionals, Promise<InetAddress> promise) Resolves the specified name into an address.
Future<List<InetAddress>>	resolveAll(String inetHost, Iterable<DnsRecord> additionals) Resolves the specified host name and port into a list of address.
Future<List<InetAddress>>	resolveAll(String inetHost, Iterable<DnsRecord> additionals, Promise<List<InetAddress>> promise) Resolves the specified host name and port into a list of address.
DnsCache	resolveCache() Returns the resolution cache.
ResolvedAddressTypes	resolvedAddressTypes() Returns the ResolvedAddressTypes resolved by SimpleNameResolver.resolve(String).
protected DnsServerAddressStream	uncachedRedirectDnsServerStream(List<InetSocketAddress> nameServers) Provides the opportunity to sort the name servers before following a redirected DNS query.

Methods inherited from class io.netty.resolver.InetNameResolver

asAddressResolver

Methods inherited from class io.netty.resolver.SimpleNameResolver

resolve, resolve, resolveAll, resolveAll

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DnsNameResolver

public DnsNameResolver(EventLoop eventLoop,
                       ChannelFactory<? extends DatagramChannel> channelFactory,
                       DnsCache resolveCache,
                       DnsCache authoritativeDnsServerCache,
                       DnsQueryLifecycleObserverFactory dnsQueryLifecycleObserverFactory,
                       long queryTimeoutMillis,
                       ResolvedAddressTypes resolvedAddressTypes,
                       boolean recursionDesired,
                       int maxQueriesPerResolve,
                       boolean traceEnabled,
                       int maxPayloadSize,
                       boolean optResourceEnabled,
                       HostsFileEntriesResolver hostsFileEntriesResolver,
                       DnsServerAddressStreamProvider dnsServerAddressStreamProvider,
                       String[] searchDomains,
                       int ndots,
                       boolean decodeIdn)

Creates a new DNS-based name resolver that communicates with the specified list of DNS servers.

Parameters:

eventLoop - the EventLoop which will perform the communication with the DNS servers

channelFactory - the ChannelFactory that will create a DatagramChannel

resolveCache - the DNS resolved entries cache

authoritativeDnsServerCache - the cache used to find the authoritative DNS server for a domain

dnsQueryLifecycleObserverFactory - used to generate new instances of DnsQueryLifecycleObserver which can be used to track metrics for DNS servers.

queryTimeoutMillis - timeout of each DNS query in millis

resolvedAddressTypes - the preferred address types

recursionDesired - if recursion desired flag must be set

maxQueriesPerResolve - the maximum allowed number of DNS queries for a given name resolution

traceEnabled - if trace is enabled

maxPayloadSize - the capacity of the datagram packet buffer

optResourceEnabled - if automatic inclusion of a optional records is enabled

hostsFileEntriesResolver - the HostsFileEntriesResolver used to check for local aliases

dnsServerAddressStreamProvider - The DnsServerAddressStreamProvider used to determine the name servers for each hostname lookup.

searchDomains - the list of search domain

ndots - the ndots value

decodeIdn - true if domain / host names should be decoded to unicode when received. See rfc3492.

Method Detail

uncachedRedirectDnsServerStream

protected DnsServerAddressStream uncachedRedirectDnsServerStream(List<InetSocketAddress> nameServers)

Provides the opportunity to sort the name servers before following a redirected DNS query.

Parameters:

nameServers - The addresses of the DNS servers which are used in the event of a redirect.

Returns:

A DnsServerAddressStream which will be used to follow the DNS redirect.

resolveCache

public DnsCache resolveCache()

Returns the resolution cache.

authoritativeDnsServerCache

public DnsCache authoritativeDnsServerCache()

Returns the cache used for authoritative DNS servers for a domain.

queryTimeoutMillis

public long queryTimeoutMillis()

Returns the timeout of each DNS query performed by this resolver (in milliseconds). The default value is 5 seconds.

resolvedAddressTypes

public ResolvedAddressTypes resolvedAddressTypes()

Returns the ResolvedAddressTypes resolved by SimpleNameResolver.resolve(String). The default value depends on the value of the system property "java.net.preferIPv6Addresses".

isRecursionDesired

public boolean isRecursionDesired()

Returns true if and only if this resolver sends a DNS query with the RD (recursion desired) flag set. The default value is true.

maxQueriesPerResolve

public int maxQueriesPerResolve()

Returns the maximum allowed number of DNS queries to send when resolving a host name. The default value is 8.

isTraceEnabled

public boolean isTraceEnabled()

Returns if this resolver should generate the detailed trace information in an exception message so that it is easier to understand the cause of resolution failure. The default value if true.

maxPayloadSize

public int maxPayloadSize()

Returns the capacity of the datagram packet buffer (in bytes). The default value is 4096 bytes.

isOptResourceEnabled

public boolean isOptResourceEnabled()

Returns the automatic inclusion of a optional records that tries to give the remote DNS server a hint about how much data the resolver can read per response is enabled.

hostsFileEntriesResolver

public HostsFileEntriesResolver hostsFileEntriesResolver()

Returns the component that tries to resolve hostnames against the hosts file prior to asking to remotes DNS servers.

close

public void close()

Closes the internal datagram channel used for sending and receiving DNS messages, and clears all DNS resource records from the cache. Attempting to send a DNS query or to resolve a domain name will fail once this method has been called.

Specified by:

close in interface NameResolver<InetAddress>

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class SimpleNameResolver<InetAddress>

executor

protected EventLoop executor()

Description copied from class: SimpleNameResolver

Returns the EventExecutor which is used to notify the listeners of the Future returned by SimpleNameResolver.resolve(String).

Overrides:

executor in class SimpleNameResolver<InetAddress>

resolve

public final Future<InetAddress> resolve(String inetHost,
                                         Iterable<DnsRecord> additionals)

Resolves the specified name into an address.

Parameters:

inetHost - the name to resolve

additionals - additional records (OPT)

Returns:

the address as the result of the resolution

resolve

public final Future<InetAddress> resolve(String inetHost,
                                         Iterable<DnsRecord> additionals,
                                         Promise<InetAddress> promise)

Resolves the specified name into an address.

Parameters:

inetHost - the name to resolve

additionals - additional records (OPT)

promise - the Promise which will be fulfilled when the name resolution is finished

Returns:

the address as the result of the resolution

resolveAll

public final Future<List<InetAddress>> resolveAll(String inetHost,
                                                  Iterable<DnsRecord> additionals)

Resolves the specified host name and port into a list of address.

Parameters:

inetHost - the name to resolve

additionals - additional records (OPT)

Returns:

the list of the address as the result of the resolution

resolveAll

public final Future<List<InetAddress>> resolveAll(String inetHost,
                                                  Iterable<DnsRecord> additionals,
                                                  Promise<List<InetAddress>> promise)

Resolves the specified host name and port into a list of address.

Parameters:

inetHost - the name to resolve

additionals - additional records (OPT)

promise - the Promise which will be fulfilled when the name resolution is finished

Returns:

the list of the address as the result of the resolution

doResolve

protected void doResolve(String inetHost,
                         Promise<InetAddress> promise)
                  throws Exception

Description copied from class: SimpleNameResolver

Invoked by SimpleNameResolver.resolve(String) to perform the actual name resolution.

Specified by:

doResolve in class SimpleNameResolver<InetAddress>

Throws:

Exception

doResolve

protected void doResolve(String inetHost,
                         DnsRecord[] additionals,
                         Promise<InetAddress> promise,
                         DnsCache resolveCache)
                  throws Exception

Hook designed for extensibility so one can pass a different cache on each resolution attempt instead of using the global one.

Throws:

Exception

doResolveAll

protected void doResolveAll(String inetHost,
                            Promise<List<InetAddress>> promise)
                     throws Exception

Description copied from class: SimpleNameResolver

Invoked by SimpleNameResolver.resolveAll(String) to perform the actual name resolution.

Specified by:

doResolveAll in class SimpleNameResolver<InetAddress>

Throws:

Exception

doResolveAll

protected void doResolveAll(String inetHost,
                            DnsRecord[] additionals,
                            Promise<List<InetAddress>> promise,
                            DnsCache resolveCache)
                     throws Exception

Hook designed for extensibility so one can pass a different cache on each resolution attempt instead of using the global one.

Throws:

Exception

query

public Future<AddressedEnvelope<DnsResponse,InetSocketAddress>> query(DnsQuestion question)

Sends a DNS query with the specified question.

query

public Future<AddressedEnvelope<DnsResponse,InetSocketAddress>> query(DnsQuestion question,
                                                                      Iterable<DnsRecord> additionals)

Sends a DNS query with the specified question with additional records.

query

public Future<AddressedEnvelope<DnsResponse,InetSocketAddress>> query(DnsQuestion question,
                                                                      Promise<AddressedEnvelope<? extends DnsResponse,InetSocketAddress>> promise)

Sends a DNS query with the specified question.

query

public Future<AddressedEnvelope<DnsResponse,InetSocketAddress>> query(InetSocketAddress nameServerAddr,
                                                                      DnsQuestion question)

Sends a DNS query with the specified question using the specified name server list.

query

public Future<AddressedEnvelope<DnsResponse,InetSocketAddress>> query(InetSocketAddress nameServerAddr,
                                                                      DnsQuestion question,
                                                                      Iterable<DnsRecord> additionals)

Sends a DNS query with the specified question with additional records using the specified name server list.

query

public Future<AddressedEnvelope<DnsResponse,InetSocketAddress>> query(InetSocketAddress nameServerAddr,
                                                                      DnsQuestion question,
                                                                      Promise<AddressedEnvelope<? extends DnsResponse,InetSocketAddress>> promise)

Sends a DNS query with the specified question using the specified name server list.

query

public Future<AddressedEnvelope<DnsResponse,InetSocketAddress>> query(InetSocketAddress nameServerAddr,
                                                                      DnsQuestion question,
                                                                      Iterable<DnsRecord> additionals,
                                                                      Promise<AddressedEnvelope<? extends DnsResponse,InetSocketAddress>> promise)

Sends a DNS query with the specified question with additional records using the specified name server list.