Module decoder

JSON (RFC 7159) decoder implementation.

The decoder supports direct decoding into Rust types (providing helper macros such as object!) as well as generic decoding using an intermediate representation.

Example 1: Generic decoding

use json::{Decoder, Json};
use json::ast::Ref;

let json = r#"
{ "field1": true,
  "field2": { "nested": [42, 73] }
}"#;

let mut d = Decoder::default(json.chars());
let     v = d.decode().unwrap();
let     r = Ref::new(&v);
assert_eq!(true, r.get("field1").bool().unwrap());
assert_eq!(73f64, r.get("field2").get("nested").at(1).number().unwrap());

Example 2: Direct decoding using macros

#[macro_use] extern crate json;

use json::Decoder;

const JSON: &'static str =
r#"
{
    "Width":  800,
    "Height": 600,
    "Title":  "View from 15th Floor",
    "Thumbnail": {
        "Url":    "http://www.example.com/image/481989943",
        "Height": 125,
        "Width":  100
    },
    "Animated" : false,
    "IDs": [116, 943, 234, 38793]
}
"#;

struct Image {
    width:     usize,
    height:    usize,
    title:     String,
    thumbnail: Thumbnail,
    animated:  bool,
    ids:       Vec<u32>,
    geo:       Option<(f64, f64)>
}

struct Thumbnail {
    url:    String,
    height: u16,
    width:  u16
}

let mut d = Decoder::default(JSON.chars());
let image = object! {
    let decoder = d;
    Image {
        width:     req. "Width"     => d.usize(),
        height:    req. "Height"    => d.usize(),
        title:     req. "Title"     => d.string(),
        thumbnail: req. "Thumbnail" => object! {
            let decoder = d;
            Thumbnail {
                url:    req. "Url"    => d.string(),
                height: req. "Height" => d.u16(),
                width:  req. "Width"  => d.u16()
            }
        },
        animated:  req. "Animated" => d.bool(),
        ids:       req. "IDs"      => array!(d, d.u32()),
        geo:       opt. "Geo"      => d.optional(|d| {
            let lat = d.f64()?;
            let lon = d.f64()?;
            Ok((lat, lon))
        })
    }
};
assert!(image.is_ok());

Structs

ArrayIter

Iterator over JSON array elements.

Config

Decoder configuration.

Decoder

JSON decoder over char iterators.

ReadIter

Iterator over characters read from any Read-type.

Enums

DecodeError

ReadError

Traits

FromJson

Type Aliases

DecodeResult