DNSOverHTTPS (Javadocs [I2P+ 2.13.0+]

java.lang.Object
- net.i2p.util.DNSOverHTTPS

All Implemented Interfaces:
EepGet.StatusListener
```
public class DNSOverHTTPS
extends Object
implements EepGet.StatusListener
```
Simple implemetation of DNS over HTTPS. Also sets the local clock from the received date header. Warning - not thread-safe. Create new instances as necessary. As of 0.9.49, this supports the RFC 8484 (DNS) format only. Does NOT support the JSON format (used prior to 0.9.49) or RFC 7858 (DNS over TLS). https://developers.google.com/speed/public-dns/docs/dns-over-https https://developers.cloudflare.com/1.1.1.1/dns-over-https/json-format/ https://github.com/curl/curl/wiki/DNS-over-HTTPS

Nested Class Summary
Nested Classes
Modifier and Type Class and Description
static class DNSOverHTTPS.Type
DNS query type for IPv4/IPv6 preference.

Nested Classes
Modifier and Type	Class and Description
`static class`	`DNSOverHTTPS.Type` DNS query type for IPv4/IPv6 preference.

Field Summary
Fields
Modifier and Type Field and Description
static String UA_CLEARNET
ESR version of Firefox, same as Tor Browser

Fields
Modifier and Type	Field and Description
`static String`	`UA_CLEARNET` ESR version of Firefox, same as Tor Browser

Constructor Summary

Constructors
Constructor and Description
`DNSOverHTTPS(I2PAppContext context)` Create a DNSOverHTTPS instance.
`DNSOverHTTPS(I2PAppContext context, SSLEepGet.SSLState sslState)` Create a DNSOverHTTPS instance.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`attemptFailed(String url, long bytesTransferred, long bytesRemaining, int currentAttempt, int numRetries, Exception cause)` Attempt failed notification.
`void`	`attempting(String url)` Called when a new attempt to fetch the URL is starting.
`void`	`bytesTransferred(long alreadyTransferred, int currentWrite, long bytesTransferred, long bytesRemaining, String url)` Total length should be == alreadyTransferred + currentWrite + bytesRemaining for all calls.
`static void`	`clearCaches()` Clear DNS caches and fail counts.
`void`	`headerReceived(String url, int attemptNum, String key, String val)` Use the Date header as a backup time source.
`String`	`lookup(String host)` V4_ONLY unless we have only IPv6 address, then V6_ONLY
`String`	`lookup(String host, DNSOverHTTPS.Type type)` Lookup in cache, then query servers
`static void`	`main(String[] args)` Main entry point for command line usage.
`void`	`transferComplete(long alreadyTransferred, long bytesTransferred, long bytesRemaining, String url, String outputFile, boolean notModified)` Transfer complete notification.
`void`	`transferFailed(String url, long bytesTransferred, long bytesRemaining, int currentAttempt)` Transfer failed notification.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - UA_CLEARNET
```
public static final String UA_CLEARNET
```
    ESR version of Firefox, same as Tor Browser
    See Also:
    Constant Field Values
- Constructor Detail
  - DNSOverHTTPS
```
public DNSOverHTTPS(I2PAppContext context)
```
    Create a DNSOverHTTPS instance.
    Parameters:
    context - the I2P app context
  - DNSOverHTTPS
```
public DNSOverHTTPS(I2PAppContext context,
                    SSLEepGet.SSLState sslState)
```
    Create a DNSOverHTTPS instance.
    Parameters:
    context - the I2P app context
    sslState - the SSL state, or null
- Method Detail
  - attemptFailed
```
public void attemptFailed(String url,
                          long bytesTransferred,
                          long bytesRemaining,
                          int currentAttempt,
                          int numRetries,
                          Exception cause)
```
    Description copied from interface: EepGet.StatusListener
    Attempt failed notification.
    Specified by:
    attemptFailed in interface EepGet.StatusListener
    Parameters:
    url - the URL
    bytesTransferred - total transferred
    bytesRemaining - remaining
    currentAttempt - attempt index
    numRetries - retry limit
    cause - failure cause
    See Also:
    EepGet.StatusListener.bytesTransferred(long, int, long, long, java.lang.String)
  - attempting
```
public void attempting(String url)
```
    Description copied from interface: EepGet.StatusListener
    Called when a new attempt to fetch the URL is starting.
    Specified by:
    attempting in interface EepGet.StatusListener
    Parameters:
    url - the URL being attempted
  - bytesTransferred
```
public void bytesTransferred(long alreadyTransferred,
                             int currentWrite,
                             long bytesTransferred,
                             long bytesRemaining,
                             String url)
```
    Description copied from interface: EepGet.StatusListener
    Total length should be == alreadyTransferred + currentWrite + bytesRemaining for all calls.
    Specified by:
    bytesTransferred in interface EepGet.StatusListener
    Parameters:
    alreadyTransferred - total of all attempts, not including currentWrite If nonzero on the first call, a partial file of that length was found, _and_ the server supports resume. If zero on a subsequent call after some bytes are transferred (and presumably after an attemptFailed), the server does _not_ support resume and we had to start over. To track _actual_ transfer if the output file could already exist, the listener should keep its own counter, or subtract the initial alreadyTransferred value. And watch out for alreadyTransferred resetting if a resume failed...
    currentWrite - since last call to the listener
    bytesTransferred - includes headers, retries, redirects, discarded partial downloads, ...
    bytesRemaining - on this attempt only, currentWrite already subtracted - or -1 if chunked encoding or server does not return a length
    url - the URL being fetched
  - clearCaches
```
public static void clearCaches()
```
    Clear DNS caches and fail counts.
  - headerReceived
```
public void headerReceived(String url,
                           int attemptNum,
                           String key,
                           String val)
```
    Use the Date header as a backup time source. Code from Reseeder. We set the stratum to a lower (better) value than in Reseeder, as Cloudflare and Google probably have a better idea than our reseeds.
    Specified by:
    headerReceived in interface EepGet.StatusListener
    Parameters:
    url - the URL
    attemptNum - attempt index
    key - header key
    val - header value
  - lookup
```
public String lookup(String host)
```
    V4_ONLY unless we have only IPv6 address, then V6_ONLY
    Parameters:
    host - the hostname to resolve
    Returns:
    null if not found
  - lookup
```
public String lookup(String host,
                     DNSOverHTTPS.Type type)
```
    Lookup in cache, then query servers
    Parameters:
    host - the hostname to resolve
    type - the query type
    Returns:
    null if not found
  - main
```
public static void main(String[] args)
```
    Main entry point for command line usage.
    Parameters:
    args - command line arguments
  - transferComplete
```
public void transferComplete(long alreadyTransferred,
                             long bytesTransferred,
                             long bytesRemaining,
                             String url,
                             String outputFile,
                             boolean notModified)
```
    Description copied from interface: EepGet.StatusListener
    Transfer complete notification.
    Specified by:
    transferComplete in interface EepGet.StatusListener
    Parameters:
    alreadyTransferred - total bytes transferred
    bytesTransferred - total incl headers
    bytesRemaining - remaining bytes
    url - the URL
    outputFile - null if unknown (output stream constructor)
    notModified - whether 304
    See Also:
    EepGet.StatusListener.bytesTransferred(long, int, long, long, java.lang.String)
  - transferFailed
```
public void transferFailed(String url,
                           long bytesTransferred,
                           long bytesRemaining,
                           int currentAttempt)
```
    Description copied from interface: EepGet.StatusListener
    Transfer failed notification.
    Specified by:
    transferFailed in interface EepGet.StatusListener
    Parameters:
    url - the URL
    bytesTransferred - total transferred
    bytesRemaining - remaining
    currentAttempt - attempt index
    See Also:
    EepGet.StatusListener.bytesTransferred(long, int, long, long, java.lang.String)

Class DNSOverHTTPS

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

UA_CLEARNET

Constructor Detail

DNSOverHTTPS

DNSOverHTTPS

Method Detail

attemptFailed

attempting

bytesTransferred

clearCaches

headerReceived

lookup

lookup

main

transferComplete

transferFailed