leptos-use/src/storage/codec_prost.rs

80 lines
2.6 KiB
Rust
Raw Normal View History

use super::Codec;
use base64::Engine;
use thiserror::Error;
2023-10-29 11:41:59 +00:00
/// A codec for storing ProtoBuf messages that relies on [`prost`] to parse.
///
/// [Protocol buffers](https://protobuf.dev/overview/) is a serialisation format useful for long-term storage. It provides semantics for versioning that are not present in JSON or other formats. [`prost`] is a Rust implementation of Protocol Buffers.
///
/// This codec uses [`prost`] to encode the message and then [`base64`](https://docs.rs/base64) to represent the bytes as a string.
///
/// ## Example
/// ```
/// # use leptos::*;
2023-11-12 22:50:59 +00:00
/// # use leptos_use::storage::{StorageType, use_local_storage, use_session_storage, use_storage, UseStorageOptions, ProstCodec};
2023-10-29 11:41:59 +00:00
/// #
/// # pub fn Demo() -> impl IntoView {
/// // Primitive types:
/// let (get, set, remove) = use_local_storage::<i32, ProstCodec>("my-key");
///
/// // Structs:
/// #[derive(Clone, PartialEq, prost::Message)]
/// pub struct MyState {
/// #[prost(string, tag = "1")]
/// pub hello: String,
/// }
/// let (get, set, remove) = use_local_storage::<MyState, ProstCodec>("my-struct-key");
/// # view! { }
/// # }
/// ```
///
/// Note: we've defined and used the `prost` attribute here for brevity. Alternate usage would be to describe the message in a .proto file and use [`prost_build`](https://docs.rs/prost-build) to auto-generate the Rust code.
#[derive(Clone, Default, PartialEq)]
pub struct ProstCodec();
#[derive(Error, Debug, PartialEq)]
pub enum ProstCodecError {
#[error("failed to decode base64")]
DecodeBase64(base64::DecodeError),
#[error("failed to decode protobuf")]
DecodeProst(#[from] prost::DecodeError),
}
impl<T: Default + prost::Message> Codec<T> for ProstCodec {
type Error = ProstCodecError;
fn encode(&self, val: &T) -> Result<String, Self::Error> {
let buf = val.encode_to_vec();
Ok(base64::engine::general_purpose::STANDARD.encode(buf))
}
fn decode(&self, str: String) -> Result<T, Self::Error> {
let buf = base64::engine::general_purpose::STANDARD
.decode(str)
.map_err(ProstCodecError::DecodeBase64)?;
T::decode(buf.as_slice()).map_err(ProstCodecError::DecodeProst)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_prost_codec() {
#[derive(Clone, PartialEq, prost::Message)]
struct Test {
#[prost(string, tag = "1")]
s: String,
#[prost(int32, tag = "2")]
i: i32,
}
let t = Test {
s: String::from("party time 🎉"),
i: 42,
};
let codec = ProstCodec();
assert_eq!(codec.decode(codec.encode(&t).unwrap()), Ok(t));
}
}