DnsOptions
public
final
class
DnsOptions
extends Object
java.lang.Object | |
↳ | android.net.http.DnsOptions |
A class configuring the host resolution functionality. Note that while we refer to DNS
as the most common mechanism being used for brevity, settings apply to other means of
resolving hostnames like hosts file resolution.
Hostnames can be resolved in two ways - either by using the system resolver (using getaddrinfo
provided by system libraries), or by using a custom resolver which is tailored
for the HTTP networking stack.
The built-in stack provides several advantages over using the global system resolver:
- It has been tailored to the needs of the HTTP networking stack, particularly speed and stability.
getaddrinfo
is a blocking call which requires dedicating worker threads and makes cancellation impossible (we need to abandon the thread until the call completes)- The
getaddrinfo
interface gives no insight into the root cause of failures struct addrinfo
provides no TTL (Time To Live) of the returned addresses. This restricts flexibility of handling caching (e.g. allowing the use of stale DNS records) and requires us to either rely on OS DNS caches, or be extremely conservative with the TTL.
Most configuration in this class is only applicable if the built-in DNS resolver is used.
Summary
Nested classes | |
---|---|
class |
DnsOptions.Builder
Builder for |
class |
DnsOptions.StaleDnsOptions
A class configuring the stale DNS functionality. |
Constants | |
---|---|
int |
DNS_OPTION_DISABLED
Option is disabled. |
int |
DNS_OPTION_ENABLED
Option is enabled. |
int |
DNS_OPTION_UNSPECIFIED
Option is unspecified, platform default value will be used. |
Inherited methods | |
---|---|
Constants
DNS_OPTION_DISABLED
public static final int DNS_OPTION_DISABLED
Option is disabled.
Constant Value: 2 (0x00000002)
DNS_OPTION_ENABLED
public static final int DNS_OPTION_ENABLED
Option is enabled.
Constant Value: 1 (0x00000001)
DNS_OPTION_UNSPECIFIED
public static final int DNS_OPTION_UNSPECIFIED
Option is unspecified, platform default value will be used.
Constant Value: 0 (0x00000000)
Public methods
getPersistHostCache
public int getPersistHostCache ()
See Builder#setPersistHostCache(int)
Returns | |
---|---|
int |
Value is DNS_OPTION_UNSPECIFIED , DNS_OPTION_ENABLED , or DNS_OPTION_DISABLED |
getPersistHostCachePeriod
public Duration getPersistHostCachePeriod ()
See Builder#setPersistHostCachePeriod
Returns | |
---|---|
Duration |
This value may be null . |
getPreestablishConnectionsToStaleDnsResults
public int getPreestablishConnectionsToStaleDnsResults ()
See Builder#setPreestablishConnectionsToStaleDnsResults(int)
Returns | |
---|---|
int |
Value is DNS_OPTION_UNSPECIFIED , DNS_OPTION_ENABLED , or DNS_OPTION_DISABLED |
getStaleDns
public int getStaleDns ()
Returns | |
---|---|
int |
Value is DNS_OPTION_UNSPECIFIED , DNS_OPTION_ENABLED , or DNS_OPTION_DISABLED |
getStaleDnsOptions
public DnsOptions.StaleDnsOptions getStaleDnsOptions ()
See Builder#setStaleDnsOptions
Returns | |
---|---|
DnsOptions.StaleDnsOptions |
This value may be null . |
getUseHttpStackDnsResolver
public int getUseHttpStackDnsResolver ()
See Builder#setUseHttpStackDnsResolver(int)
Returns | |
---|---|
int |
Value is DNS_OPTION_UNSPECIFIED , DNS_OPTION_ENABLED , or DNS_OPTION_DISABLED |
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Last updated 2024-04-04 UTC.