# Borsh in Rust   [![Build Status]][travis-ci] [![Latest Version]][crates.io] [![borsh: rustc 1.40+]][Rust 1.40] [![License Apache-2.0 badge]][License Apache-2.0] [![License MIT badge]][License MIT]
[Borsh]: https://borsh.io
[Build Status]: https://travis-ci.com/near/borsh-rs.svg?branch=master
[travis-ci]: https://travis-ci.com/near/borsh-rs
[Latest Version]: https://img.shields.io/crates/v/borsh.svg
[crates.io]: https://crates.io/crates/borsh
[borsh: rustc 1.40+]: https://img.shields.io/badge/rustc-1.40+-lightgray.svg
[Rust 1.40]: https://blog.rust-lang.org/2019/12/19/Rust-1.40.0.html
[License Apache-2.0 badge]: https://img.shields.io/badge/license-Apache2.0-blue.svg
[License Apache-2.0]: https://opensource.org/licenses/Apache-2.0
[License MIT badge]: https://img.shields.io/badge/license-MIT-blue.svg
[License MIT]: https://opensource.org/licenses/MIT
**borsh-rs** is Rust implementation of the [Borsh] binary serialization format.
Borsh stands for _Binary Object Representation Serializer for Hashing_. It is meant to be used in
security-critical projects as it prioritizes [consistency, safety, speed][Borsh], and comes with a
strict [specification](https://github.com/near/borsh#specification).
## Example
```rust
use borsh::{BorshSerialize, BorshDeserialize};
#[derive(BorshSerialize, BorshDeserialize, PartialEq, Debug)]
struct A {
x: u64,
y: String,
}
#[test]
fn test_simple_struct() {
let a = A {
x: 3301,
y: "liber primus".to_string(),
};
let encoded_a = a.try_to_vec().unwrap();
let decoded_a = A::try_from_slice(&encoded_a).unwrap();
assert_eq!(a, decoded_a);
}
```
## Features
Opting out from Serde allows borsh to have some features that currently are not available for serde-compatible serializers.
Currently we support two features: `borsh_init` and `borsh_skip` (the former one not available in Serde).
`borsh_init` allows to automatically run an initialization function right after deserialization. This adds a lot of convenience for objects that are architectured to be used as strictly immutable. Usage example:
```rust
#[derive(BorshSerialize, BorshDeserialize)]
#[borsh_init(init)]
struct Message {
message: String,
timestamp: u64,
public_key: CryptoKey,
signature: CryptoSignature
hash: CryptoHash
}
impl Message {
pub fn init(&mut self) {
self.hash = CryptoHash::new().write_string(self.message).write_u64(self.timestamp);
self.signature.verify(self.hash, self.public_key);
}
}
```
`borsh_skip` allows to skip serializing/deserializing fields, assuming they implement `Default` trait, similary to `#[serde(skip)]`.
```rust
#[derive(BorshSerialize, BorshDeserialize)]
struct A {
x: u64,
#[borsh_skip]
y: f32,
}
```
## Releasing
After you merged your change into the master branch and bumped the versions of all three crates it is time to officially release the new version.
Make sure `borsh`, `borsh-derive` and `borsh-derive-internal` all have the new crate versions. Then navigate to each folder and run (in the given order):
```bash
cd ../borsh-derive-internal; cargo publish
cd ../borsh-derive; cargo publish
cd ../borsh; cargo publish
```
Make sure you are on the master branch, then tag the code and push the tag:
```bash
git tag -a v9.9.9 -m "My superawesome change."
git push origin v9.9.9
```
## License
This repository is distributed under the terms of both the MIT license and the Apache License (Version 2.0).
See [LICENSE-MIT](LICENSE-MIT) and [LICENSE-APACHE](LICENSE-APACHE) for details.