Read lists of JSON structures JSON-lines

TODO

• JSON lines

• See also jsonl, json-lines

{ "name": "Foo", "number": 10 }
{ "name": "Bar", "number": 20 }

Code

use serde::Deserialize;

#[derive(Deserialize, Debug)]
#[allow(dead_code)]
struct Thing {
    name: String,
    number: u32,
}

fn main() {
    let filename = "data.json";
    let content = std::fs::read_to_string(filename).unwrap();
    for row in content.split('\n') {
        if row.is_empty() {
            continue;
        }
        //println!("row: {row}");
        let data = serde_json::from_str::<Thing>(row).unwrap();
        println!("data: {data:#?}");
    }

    // let mut content_as_bytes = std::fs::read(filename).unwrap();
    // json_lines::from_bytes(&mut content_as_bytes)
    //     .map(|thing: Thing| {
    //         println!("thing: {thing:#?}");
    //     })
    //     .unwrap();
}

Output

data: Thing {
    name: "Foo",
    number: 10,
}
data: Thing {
    name: "Bar",
    number: 20,
}

Cargo.toml

[package]
name = "read-list-of-json"
version = "0.1.0"
edition = "2024"

[dependencies]
json-lines = "0.1.1"
serde = { version = "1.0.204", features = ["derive"] }
serde_json = "1.0.120"