v2.0.1-beta

New Changes

• ttl_cache now expects a duration_s argument to explicitly state the cache duration
• Added a only_ok argument to limit caching to Ok(T) variants from a function returning a Result<T, E> (#1)
• Added a only_some argument to limit caching to Some(T) variants of an Option<T> (#1)

Examples

• only_ok

// only_ok option ensures that only .is_ok values from the returning Result are cached
#[ttl_cache(duration_s = 30, only_ok = true)] 
fn some_fallible_function(n: u32) -> Result<u32, String> {
    if n == 0 {
        return Err(String::from("zeros are not allowed"))
    }
    Ok(n)
}

fn main() {
     // zero is not cached since function returns an Err since n == 0
    println!("last: {}", some_fallible_function(0));
    // cache miss: 10 is cached since the result is_ok
    println!("last: {}", some_fallible_function(10));
    // cache hit: 10 is retrieved from the cache
    println!("last: {}", some_fallible_function(10));

}

• only_some

// only_some option ensures that only .is_some values from the returning Option are cached
#[ttl_cache(duration_s = 30, only_some = true)] 
fn some_optional_function(n: u32) -> Option<u32> {
    if n == 0 {
        return None;
    }
    Some(n)
}

fn main() {
     // zero is not cached since function returns None since n == 0
    println!("last: {}", some_optional_function(0));
    // cache miss: 10 is cached since the result is_some
    println!("last: {}", some_optional_function(10));
    // cache hit: 10 is retrieved from the cache
    println!("last: {}", some_optional_function(10));

}