serde-hashkey

Serde-based in-memory key serialization.

This allows any serde-serializable type to be converted into a value which implements PartialEq, Eq, ParialOrd, Ord, and Hash. The only limitation is that the type can't serialize floating point values, since these are not totally ordered nor hashable by default.

Key is useful because it allows for a form of type-erasure. Let's say you want to build a generic in-memory key-value store where you want to store arbitrary serde-serializable keys. This is typical for things like caches or dependency injection frameworks.

Examples

You can run this example with cargo run --example book

use serde_derive::{Deserialize, Serialize};
use serde_hashkey::{from_key, to_key, Error, Key};
use std::{collections::HashMap, error};

#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
struct Author {
    name: String,
    age: u32,
}

#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
struct Book {
    title: String,
    author: Author,
}

fn main() -> Result<(), Box<dyn error::Error>> {
    let book = Book {
        title: String::from("Birds of a feather"),
        author: Author {
            name: String::from("Noah"),
            age: 42,
        },
    };

    let key = to_key(&book)?;

    let mut ratings = HashMap::new();
    ratings.insert(key.clone(), 5);

    println!("ratings: {:?}", ratings);

    println!(
        "book as json (through key): {}",
        serde_json::to_string_pretty(&key)?
    );

    println!(
        "book as json (through original object): {}",
        serde_json::to_string_pretty(&book)?
    );

    Ok(())
}

License: MIT/Apache-2.0