| # 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](https://tools.ietf.org/html/rfc6763). |
| |
| [](https://travis-ci.org/watson/dns-txt) |
| [](https://github.com/feross/standard) |
| [](https://github.com/mafintosh/abstract-encoding) |
| |
| ## Installation |
| |
| ``` |
| npm install dns-txt |
| ``` |
| |
| ## Usage |
| |
| ```js |
| 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](https://tools.ietf.org/html/rfc6763). |
| |
| ### Initialize |
| |
| The module exposes a constructor function which can be called with an |
| optional options object: |
| |
| ```js |
| 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. |
| |
| #### `txt.encode(obj, [buffer], [offset])` |
| |
| 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](https://tools.ietf.org/html/rfc6763#section-6.4). |
| |
| - To be RFC compliant, each value should conform with the rules as |
| specified in [section |
| 6.5](https://tools.ietf.org/html/rfc6763#section-6.5). |
| |
| After encoding `txt.encode.bytes` is set to the amount of bytes used to |
| encode the object. |
| |
| #### `txt.decode(buffer, [offset], [length])` |
| |
| 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. |
| |
| #### `txt.encodingLength(obj)` |
| |
| Takes a single key/value object and returns the number of bytes that the given |
| object would require if encoded. |
| |
| ## License |
| |
| MIT |