tinyjson's Introduction

tinyjson

tinyjson is a library to parse/generate JSON format document.

Goals of this library are

Simplicity: This library uses standard containers like Vec or HashMap as its internal representation and exposes it to users. Users can operate JSON values via the standard APIs. And it keeps this crate as small as possible.
Explicit: This library does not hide memory allocation from users. You need to allocate memory like Vec, String, HashMap by yourself. It is good for readers of your source code to show where memory allocations happen. And you can have control of how memory is allocated (e.g. allocating memory in advance with with_capacity method).
No dependencies: This library is built on top of only standard libraries.
No unsafe code: This library is built with Safe Rust.
Well tested: This library is tested with famous test suites:

Documentation

Requirements

Rust stable toolchain.

Installation

Add this crate to dependencies section of your Cargo.toml

[dependencies]
tinyjson = "2"

Example

use tinyjson::JsonValue;
use std::collections::HashMap;
use std::convert::TryInto;

let s = r#"
    {
        "bool": true,
        "arr": [1, null, "test"],
        "nested": {
            "blah": false,
            "blahblah": 3.14
        },
        "unicode": "\u2764"
    }
"#;

// Parse from strings
let parsed: JsonValue = s.parse().unwrap();

// Access to inner value represented with standard containers
let object: &HashMap<_, _> = parsed.get().unwrap();
println!("Parsed HashMap: {:?}", object);

// Generate JSON string
println!("{}", parsed.stringify().unwrap());
// Generate formatted JSON string with indent
println!("{}", parsed.format().unwrap());

// Access nested elements by .query() or .query_mut() without panic
let elem = parsed.query().child("arr").child(1).find();
println!("Second element of \"arr\": {:?}", elem);

// Convert to inner value represented with standard containers
let object: HashMap<_, _> = parsed.try_into().unwrap();
println!("Converted into HashMap: {:?}", object);

// Create JSON values from standard containers
let mut m = HashMap::new();
m.insert("foo".to_string(), true.into());
let mut v = JsonValue::from(m);

// Access with `Index` and `IndexMut` operators quickly (panic when no element)
println!("{:?}", v["foo"]);
v["foo"] = JsonValue::from("hello".to_string());
println!("{:?}", v["foo"]);

See the document to know all APIs.

Repository

https://github.com/rhysd/tinyjson

License

the MIT License

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tinyjson's Issues

Release outdated?

The README documents the .query method, which cannot be found in the latest release v2.5.1 doc.

I suppose there are some major changes in the git repo are not published yet?

Query API

Currently it is hard to access to nested elements. ([] operator panics when the key or index doesn't exist)

We need to consider some query API to

get nested values without panic
check if some (nested) keys or indices are existing

API currently I'm thinking about:

let v: JsonValue = r#"[{"foo": true}]"#.parse().unwrap();

// Access to nested element
let found = v.query().child(0).child("foo").find();
assert_eq!(found, Some(&JsonValue::Boolean(true)));

// Check if key exists
assert!(v.query().child(0).exists());
assert!(!v.query().child(1).exists());
assert!(!v.query().child("foo").exists());

// Mutably access to nested element
let Some(found) = v.query_mut().child(0).child("foo").find() else { panic() };
*found = JsonValue::Number(10.0);
assert_eq!(v.stringify().unwrap(), "[{\"foo\":10}]");