# [Rattletrap][]

[![Windows build badge][]][windows build]
[![Build badge][]][build]

Rattletrap parses and generates [Rocket League][] replays.

## Install

Rattletrap does not yet offer compiled binaries for download. To install it,
first install [Stack][]. Then download or clone this repository and run
`stack --install-ghc install`.

## Parse

Rattletrap can parse (decode) Rocket League replays and output them as JSON.

``` sh
> rattletrap decode input.replay output.json
# or
> rattletrap decode input.replay > output.json
# or
> rattletrap.decode < input.replay > output.json
```

The resulting JSON is minified, but extremely large. A 4.3 MB replay file turns
into a 123 MB JSON file. To easily view the file, use a JSON pretty printer and
a pager. For example:

``` sh
> cat output.json | python -m json.tool | less
```

## Generate

Rattletrap can also generate (encode) Rocket League replays from JSON files.

``` sh
> rattletrap encode input.json output.replay
# or
> rattletrap encode input.json > output.replay
# or
> rattletrap.encode < input.json > output.replay
```

If the JSON was generated by Rattletrap, the resulting replay should be
identical to the original.

## Modify

By inserting another program between parsing and generating, Rattletrap can be
used to modify replays.

``` sh
> rattletrap decode < original.replay |
  modify-replay-json |
  rattletrap encode > modified.replay
```

[Rattletrap]: https://github.com/tfausak/rattletrap
[Windows build badge]: https://ci.appveyor.com/api/projects/status/github/tfausak/rattletrap?branch=master&svg=true
[windows build]: https://ci.appveyor.com/project/TaylorFausak/rattletrap
[Build badge]: https://travis-ci.org/tfausak/rattletrap.svg?branch=master
[build]: https://travis-ci.org/tfausak/rattletrap
[Rocket League]: https://www.rocketleaguegame.com
[Stack]: https://docs.haskellstack.org/en/stable/README/