jwodder / serde-jsonlines

Read & write JSON Lines documents

GitHub | crates.io | Documentation | Issues | Changelog

JSON Lines (a.k.a. newline-delimited JSON) is a simple format for storing sequences of JSON values in which each value is serialized on a single line and terminated by a newline sequence. The serde-jsonlines crate provides functionality for reading & writing these documents (whether all at once or line by line) using serde's serialization & deserialization features.

Basic usage involves simply importing the BufReadExt or WriteExt extension trait and then using the json_lines() or write_json_lines() method on a BufRead or Write value to read or write a sequence of JSON Lines values. Convenience functions are also provided for the common case of reading or writing a JSON Lines file given as a filepath.

At a lower level, values can be read or written one at a time (which is useful if, say, different lines are different types) by wrapping a BufRead or Write value in a JsonLinesReader or JsonLinesWriter and then calling the wrapped structure's read() or write() method, respectively.

When the async feature is enabled, analogous types for working with JSON Lines asynchronously under tokio become available.

Example

use serde::{Deserialize, Serialize};
use serde_jsonlines::{json_lines, write_json_lines};
use std::io::Result;

#[derive(Debug, Deserialize, Eq, PartialEq, Serialize)]
pub struct Structure {
    pub name: String,
    pub size: i32,
    pub on: bool,
}

fn main() -> Result<()> {
    let values = vec![
        Structure {
            name: "Foo Bar".into(),
            size: 42,
            on: true,
        },
        Structure {
            name: "Quux".into(),
            size: 23,
            on: false,
        },
        Structure {
            name: "Gnusto Cleesh".into(),
            size: 17,
            on: true,
        },
    ];
    write_json_lines("example.jsonl", &values)?;
    let values2 = json_lines("example.jsonl")?.collect::<Result<Vec<Structure>>>()?;
    assert_eq!(values, values2);
    Ok(())
}

serde-jsonlines's Issues

Renovate Dependency Dashboard

This issue lists Renovate updates and detected dependencies. Read the Dependency Dashboard docs to learn more.

Awaiting Schedule

These updates are awaiting their schedule. Click on a checkbox to get an update now.

• [cargo] Autoupdate Cargo.lock

Detected dependencies

cargo

Cargo.toml

• futures-core 0.3.29
• futures-sink 0.3.29
• pin-project-lite 0.2.9
• serde 1.0.147
• serde_json 1.0.87
• tokio 1.21.2
• assert_fs 1.0.7
• futures-util 0.3.29
• serde 1.0.147
• tokio 1.21.2

github-actions

.github/workflows/test.yml

• actions/checkout v4
• Swatinem/rust-cache v2
• actions/checkout v4
• Swatinem/rust-cache v2
• taiki-e/install-action v2
• actions/checkout v4
• Swatinem/rust-cache v2
• taiki-e/install-action v2
• codecov/codecov-action v4
• actions/checkout v4
• Swatinem/rust-cache v2
• actions/checkout v4
• Swatinem/rust-cache v2

---

• Check this box to trigger a request for Renovate to run again on this repository

support writing to String instead of File?

Hi,

I do not have disk where this code runs and would ideally write out the raw JSON Lines data as a byte array to my code that separately handles uploading the bytes to a file in a server.

Would that be possible to support writing to a String in memory?