Cargo.toml

[package]
name = "j2m"
version = "0.1.0"
edition = "2018"

[dependencies]
base64 = "*"
serde = "*"
serde_json = "*"
rmp-serde = "*"

mian.rs

use base64;
use rmp_serde as rmps;
use serde::Serialize;
use serde_json;
use std::io::{self, BufRead};

fn main() {
    let stdin = io::stdin();
    for line in stdin.lock().lines() {
        let line = line.unwrap();
        let j: serde_json::Value = serde_json::from_str(&line).unwrap();
        let m = rmps::to_vec(&j).unwrap();
        println!("{}", base64::encode(&m));
    }
}