Rust: Redis のデータを読む (Read)

$ tree -L 2
.
├── Cargo.lock
├── Cargo.toml
├── src
│   └── main.rs
└── target
    └── debug

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

#

[dependencies.redis]
version = "*"

[dependencies]
tokio = { version = "0.2", features = ["full"] }
serde = { version = "1.0", features = ["derive"] }
serde_json = "1.0"

// --------------------------------------------------------------------
/*
    redis_read/src/main.rs

                    Jul/22/2020
*/
// --------------------------------------------------------------------
extern crate redis;
use redis::{Commands};

fn main() -> Result<(), Box<dyn std::error::Error>>  {
    eprintln! ("*** 開始 ***");

    let client = redis::Client::open("redis://localhost/").expect("url error");
    let mut conn = client.get_connection().expect("connect error");

    let mut keys : Vec<String> = conn.keys("t*")?;

    println!("{}",keys.len());

    keys.sort();

    for it in &keys{
        let res = conn.get(it.to_string());

        let answer: String = res.unwrap();

        let json: serde_json::Value = serde_json::from_str(&answer)?;

        let obj = json.as_object().unwrap();

        let str_out = it.to_string() + "\t"
            + &obj["name"].to_string() + "\t"
            + &obj["population"].to_string() + "\t"
            + &obj["date_mod"].to_string();

        println!("{}",str_out);
        }


    eprintln! ("*** 終了 ***");

    Ok(())
}

// --------------------------------------------------------------------

cargo build

cargo run