objcache/README.md

objcache

Cache serde-able objects with Redis.

Quick overview

Imagine you have the following:

1. A struct or enum that implements Serialize and Deserialize

#[derive(Serialize, Deserialize)]
struct Item {
    value: usize,
}

2. An expensive function that creates an instance of that struct or enum

async fn get_item(v: usize) -> Result<Item, Error> {
    // your business logic here
    Ok(Item { value: v })
}

3. A redis connection

let client = RedisClient::new((IpAddr::V4(Ipv4Addr::LOCALHOST), 6379)).unwrap();

This library lets you add a cache to your application by wrap()ing your function:

let item = client.wrap(
    get_item,
    &RedisCacheArgs {
        lock_name: b"item_lock",
        key_name: b"item",
        expiry: Duration::from_secs(5),
    },
)(100)
.await?;

assert_eq!(item.value, 100);

That's it! Any call to the wrapped function will reuse the latest response if it is not older than 5 seconds.

Not implemented

• Cache depending on the input parameters
• Non-async wrap functions (should be easy to implement with some refactoring)

Status

More of a proof of concept, there may be some big hidden issues.

Available methods

Method	Use case
wrap()	You want to unconditionally cache a response
wrap_opt()	Your function returns an Option<T> and you only want to cache Some responses
wrap_const()	You want to select whether or not to cache depending on a separate parameter taking CacheDecision
wrap_on()	You have a function that takes your Item and returns a CacheDecision