dweb-dns

Issue DNS lookups for Dat archives using HTTPS requests to the target host. Keeps an in-memory cache of recent lookups.

API

``js
var datDns = require('dweb-dns')()

// or, if you have a custom protocol
var datDns = require('dweb-dns')({
recordName: / name of .well-known file /
protocolRegex: / RegExp object for custom protocol /,
hashRegex: / RegExp object for custom hash i.e. /,
txtRegex: / RegExp object for DNS TXT record of custom protocol /,
})

// example:
var cabalDns = require('dweb-dns')({
recordName: 'cabal',
hashRegex: /^[0-9a-f]{64}?$/i,
protocolRegex: /^cabal:\/\/([0-9a-f]{64})/i,
txtRegex: /^"?cabalkey=([0-9a-f]{64})"?$/i
})

// resolve a name: pass the hostname by itself
datDns.resolveName('foo.com', function (err, key) { ... })
datDns.resolveName('foo.com').then(key => ...)

// dont use cached 'misses'
datDns.resolveName('foo.com', {ignoreCachedMiss: true})

// dont use the cache at all
datDns.resolveName('foo.com', {ignoreCache: true})

// dont use dns-over-https
datDns.resolveName('foo.com', {noDnsOverHttps: true})

// dont use .well-known/dat
datDns.resolveName('foo.com', {noWellknownDat: true})

// list all entries in the cache
datDns.listCache()

// clear the cache
datDns.flushCache()

// configure the DNS-over-HTTPS host used
var datDns = require('dweb-dns')({
dnsHost: 'dns.google.com',
dnsPath: '/resolve'
})

// use a persistent fallback cache
// (this is handy for persistent dns data when offline)
var datDns = require('dweb-dns')({
persistentCache: {
read: async (name, err) => {
// try lookup
// if failed, you can throw the original error:
throw err
},
write: async (name, key, ttl) => {
// write to your cache
}
}
})

// emits some events, mainly useful for logging/debugging
datDns.on('resolved', ({method, name, key}) => {...})
datDns.on('failed', ({method, name, err}) => {...})
datDns.on('cache-flushed', () => {...})
`

Spec

In detail.

Option 1 (DNS-over-HTTPS). Create a DNS TXT record witht he following schema:

`
datkey={key}
`

Option 2 (.well-known/dat). Place a file at /.well-known/dat with the following schema:

`
{dat-url}
TTL={time in seconds}
`

TTL is optional and will default to 3600 (one hour). If set to 0`, the entry is not cached.