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dns-txt

Encode or decode the RDATA field in multicast DNS TXT records. For use with DNS-Based Service Discovery. For details see RFC 6763.

# Installation

npm install dns-txt

# Usage

var txt = require('dns-txt')()
var obj = {
foo: 1,
bar: 2
}
var enc = txt.encode(obj) // <Buffer 05 66 6f 6f 3d 31 05 62 61 72 3d 32>
txt.decode(enc) // { foo: '1', bar: '2' }

# API

The encoder and decoder conforms to RFC 6763.

## Initialize

The module exposes a constructor function which can be called with an optional options object:

var txt = require('dns-txt')({ binary: true })

The options are:

- `binary` - If set to `true` all values will be returned as `Buffer` objects. The default behavior is to turn all values into strings. But according to the RFC the values can be any binary data. If you expect binary data, use this option.

### <tt>txt.encode(obj, [buffer], [offset])</tt>

Takes a key/value object and returns a buffer with the encoded TXT record. If a buffer is passed as the second argument the object should be encoded into that buffer. Otherwise a new buffer should be allocated If an offset is passed as the third argument the object should be encoded at that byte offset. The byte offset defaults to `0`.

This module does not actively validate the key/value pairs, but keep the following in rules in mind:

- To be RFC compliant, each key should conform with the rules as specified in section 6.4.
- To be RFC compliant, each value should conform with the rules as specified in section 6.5.

After encoding `txt.encode.bytes` is set to the amount of bytes used to encode the object.

### <tt>txt.decode(buffer, [offset], [length])</tt>

Takes a buffer and returns a decoded key/value object. If an offset is passed as the second argument the object should be decoded from that byte offset. The byte offset defaults to `0`. Note that all keys will be lowercased and all values will be Buffer objects.

After decoding `txt.decode.bytes` is set to the amount of bytes used to decode the object.

### <tt>txt.encodingLength(obj)</tt>

Takes a single key/value object and returns the number of bytes that the given object would require if encoded.

# License

MIT