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

public class DnsNameResolver
extends InetNameResolver

A DNS-based InetNameResolver.

Constructor Summary

Constructors

Constructor and Description

DnsNameResolver(io.netty.channel.EventLoop eventLoop, io.netty.bootstrap.ChannelFactory<? extends io.netty.channel.socket.DatagramChannel> channelFactory, InetSocketAddress localAddress, DnsServerAddresses nameServerAddresses, DnsCache resolveCache, long queryTimeoutMillis, io.netty.channel.socket.InternetProtocolFamily[] resolvedAddressTypes, boolean recursionDesired, int maxQueriesPerResolve, boolean traceEnabled, int maxPayloadSize, boolean optResourceEnabled, HostsFileEntriesResolver hostsFileEntriesResolver) Creates a new DNS-based name resolver that communicates with the specified list of DNS servers.

Method Summary

Modifier and Type	Method and Description
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, io.netty.util.concurrent.Promise<InetAddress> promise)
protected void	doResolve(String inetHost, io.netty.util.concurrent.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	doResolveAll(String inetHost, io.netty.util.concurrent.Promise<List<InetAddress>> promise)
protected void	doResolveAll(String inetHost, io.netty.util.concurrent.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 io.netty.channel.EventLoop	executor()
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.
io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(DnsQuestion question) Sends a DNS query with the specified question.
io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(DnsQuestion question, Iterable<DnsRecord> additional) Sends a DNS query with the specified question with additional records.
io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(DnsQuestion question, io.netty.util.concurrent.Promise<io.netty.channel.AddressedEnvelope<? extends DnsResponse,InetSocketAddress>> promise) Sends a DNS query with the specified question.
io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(InetSocketAddress nameServerAddr, DnsQuestion question) Sends a DNS query with the specified question using the specified name server list.
io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(InetSocketAddress nameServerAddr, DnsQuestion question, Iterable<DnsRecord> additional) Sends a DNS query with the specified question with additional records using the specified name server list.
io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(InetSocketAddress nameServerAddr, DnsQuestion question, Iterable<DnsRecord> additional, io.netty.util.concurrent.Promise<io.netty.channel.AddressedEnvelope<? extends DnsResponse,InetSocketAddress>> promise) Sends a DNS query with the specified question with additional records using the specified name server list.
io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>>	query(InetSocketAddress nameServerAddr, DnsQuestion question, io.netty.util.concurrent.Promise<io.netty.channel.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).
DnsCache	resolveCache() Returns the resolution cache.
List<io.netty.channel.socket.InternetProtocolFamily>	resolvedAddressTypes() Returns the list of the protocol families of the address resolved by SimpleNameResolver.resolve(String) in the order of preference.

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(io.netty.channel.EventLoop eventLoop,
                       io.netty.bootstrap.ChannelFactory<? extends io.netty.channel.socket.DatagramChannel> channelFactory,
                       InetSocketAddress localAddress,
                       DnsServerAddresses nameServerAddresses,
                       DnsCache resolveCache,
                       long queryTimeoutMillis,
                       io.netty.channel.socket.InternetProtocolFamily[] resolvedAddressTypes,
                       boolean recursionDesired,
                       int maxQueriesPerResolve,
                       boolean traceEnabled,
                       int maxPayloadSize,
                       boolean optResourceEnabled,
                       HostsFileEntriesResolver hostsFileEntriesResolver)

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

localAddress - the local address of the DatagramChannel

nameServerAddresses - the addresses of the DNS server. For each DNS query, a new stream is created from this to determine which DNS server should be contacted for the next retry in case of failure.

resolveCache - the DNS resolved entries cache

queryTimeoutMillis - timeout of each DNS query in millis

resolvedAddressTypes - list of the protocol families

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

Method Detail

resolveCache

public DnsCache resolveCache()

Returns the resolution cache.

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 List<io.netty.channel.socket.InternetProtocolFamily> resolvedAddressTypes()

Returns the list of the protocol families of the address resolved by SimpleNameResolver.resolve(String) in the order of preference. 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 io.netty.channel.EventLoop executor()

Overrides:

executor in class SimpleNameResolver<InetAddress>

doResolve

protected void doResolve(String inetHost,
                         io.netty.util.concurrent.Promise<InetAddress> promise)
                  throws Exception

Specified by:

doResolve in class SimpleNameResolver<InetAddress>

Throws:

Exception

doResolve

protected void doResolve(String inetHost,
                         io.netty.util.concurrent.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,
                            io.netty.util.concurrent.Promise<List<InetAddress>> promise)
                     throws Exception

Specified by:

doResolveAll in class SimpleNameResolver<InetAddress>

Throws:

Exception

doResolveAll

protected void doResolveAll(String inetHost,
                            io.netty.util.concurrent.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 io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>> query(DnsQuestion question)

Sends a DNS query with the specified question.

query

public io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>> query(DnsQuestion question,
                                                                                                                Iterable<DnsRecord> additional)

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

query

public io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>> query(DnsQuestion question,
                                                                                                                io.netty.util.concurrent.Promise<io.netty.channel.AddressedEnvelope<? extends DnsResponse,InetSocketAddress>> promise)

Sends a DNS query with the specified question.

query

public io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>> query(InetSocketAddress nameServerAddr,
                                                                                                                DnsQuestion question)

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

query

public io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>> query(InetSocketAddress nameServerAddr,
                                                                                                                DnsQuestion question,
                                                                                                                Iterable<DnsRecord> additional)

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

query

public io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>> query(InetSocketAddress nameServerAddr,
                                                                                                                DnsQuestion question,
                                                                                                                io.netty.util.concurrent.Promise<io.netty.channel.AddressedEnvelope<? extends DnsResponse,InetSocketAddress>> promise)

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

query

public io.netty.util.concurrent.Future<io.netty.channel.AddressedEnvelope<DnsResponse,InetSocketAddress>> query(InetSocketAddress nameServerAddr,
                                                                                                                DnsQuestion question,
                                                                                                                Iterable<DnsRecord> additional,
                                                                                                                io.netty.util.concurrent.Promise<io.netty.channel.AddressedEnvelope<? extends DnsResponse,InetSocketAddress>> promise)

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