Crate redis_macros

Source
Expand description

Simple macros and wrappers to redis-rs to automatically serialize and deserialize structs with serde.

§Simple usage

The simplest way to start is to derive Serialize, Deserialize, FromRedisValue, ToRedisArgs for any kind of struct… and that’s it! You can now get and set these values with regular redis commands:

use redis::{Client, Commands, RedisResult};
use redis_macros_derive::{FromRedisValue, ToRedisArgs};
use serde::{Deserialize, Serialize};

#[derive(Serialize, Deserialize)]
enum Address {
    Street(String),
    Road(String),
}

// Derive the necessary traits
#[derive(Serialize, Deserialize, FromRedisValue, ToRedisArgs)]
struct User {
    id: u32,
    name: String,
    addresses: Vec<Address>,
}

fn main () -> redis::RedisResult<()> {
    let client = redis::Client::open("redis://localhost:6379/")?;
    let mut con = client.get_connection()?;

    let user = User {
        id: 1,
        name: "Ziggy".to_string(),
        addresses: vec![
            Address::Street("Downing".to_string()),
            Address::Road("Abbey".to_string()),
        ],
    };

    // Just use it as you would a primitive
    con.set("user", user)?;
    // user and stored_user will be the same
    let stored_user: User = con.get("user")?;
}

§Usage with RedisJSON

You can even use it with RedisJSON, to extract separate parts of the object.

use redis::JsonCommands;

// Derive FromRedisValue, ToRedisArgs to the inner struct
#[derive(Serialize, Deserialize, FromRedisValue, ToRedisArgs)]
enum Address { Street(String), Road(String) }

// Simple usage is equivalent to set-get
con.json_set("user", "$", &user)?;
let stored_user: User = con.json_get("user", "$")?;

// But you can get deep values - don't forget to derive traits for these too!
let stored_address: Address = con.json_get("user", "$.addresses[0]")?;

One issue you might be facing is that redis already has overrides for some types, for example Vec, String and most primitives. For this you have to use the Json wrapper.

// This WON'T work
let stored_addresses: Vec<Address> = con.json_get("user", "$.addresses")?;

§Json wrapper with RedisJSON

To deserialize Vecs and primitive types when using RedisJSON, you cannot use the regular types, because these are non-compatible with RedisJSON. However redis-macros exports a useful wrapper struct: Json. When using RedisJSON, you can wrap your non-structs return values into this:

use redis_macros::Json;
// Return type can be wrapped into Json
let Json(stored_name): Json<String> = con.json_get("user", "$.name")?;

// It works with Vecs as well
let Json(stored_addresses): Json<Vec<Address>> = con.json_get("user", "$.addresses")?;
// ...now stored_addresses will be equal to user.addresses

If you only use RedisJSON, you can even do away with deriving FromRedisValue and ToRedisArgs, and use Json everywhere.

#[derive(Serialize, Deserialize)]
struct User { /* .. */ }

// This works with simple redis-rs
con.json_set("user", "$", &user)?;
// ...and you can get back with Json wrapper
let Json(stored_user): Json<User> = con.json_get("user", "$")?;

§Using other serializer (e.g. serde-yaml)

In case you want to use another serializer, for example serde_yaml, you can install it and use the derives, the same way you would. The only difference should be adding an attribute redis_serializer under the derive, with the library you want to serialize with. You can use any Serde serializer as long as they support from_str and to_string methods. For the full list, see: Serde data formats.


#[derive(Debug, PartialEq, Serialize, Deserialize, FromRedisValue, ToRedisArgs)]
#[redis_serializer(serde_yaml)]
struct User { /* ... */ }

Structs§

  • Json
    Json struct is a wrapper to handle the return types from the RedisJSON commands.

Derive Macros§