Fast iterable JSON parser.
Documentation is available at docs.rs/jiter.
jiter has three interfaces:
- [
JsonValue] an enum representing JSON data - [
Jiter] an iterator over JSON data - [
python_parse] which parses a JSON string into a Python object
See [the JsonValue docs][JsonValue] for more details.
use jiter::JsonValue;
fn main() {
let json_data = r#"
{
"name": "John Doe",
"age": 43,
"phones": [
"+44 1234567",
"+44 2345678"
]
}"#;
let json_value = JsonValue::parse(json_data.as_bytes(), true).unwrap();
println!("{:#?}", json_value);
}returns:
Object(
{
"name": Str("John Doe"),
"age": Int(43),
"phones": Array(
[
Str("+44 1234567"),
Str("+44 2345678"),
],
),
},
)
To use [Jiter], you need to know what schema you're expecting:
use jiter::{Jiter, NumberInt, Peek};
fn main() {
let json_data = r#"
{
"name": "John Doe",
"age": 43,
"phones": [
"+44 1234567",
"+44 2345678"
]
}"#;
let mut jiter = Jiter::new(json_data.as_bytes(), true);
assert_eq!(jiter.next_object().unwrap(), Some("name"));
assert_eq!(jiter.next_str().unwrap(), "John Doe");
assert_eq!(jiter.next_key().unwrap(), Some("age"));
assert_eq!(jiter.next_int().unwrap(), NumberInt::Int(43));
assert_eq!(jiter.next_key().unwrap(), Some("phones"));
assert_eq!(jiter.next_array().unwrap(), Some(Peek::String));
// we know the next value is a string as we just asserted so
assert_eq!(jiter.known_str().unwrap(), "+44 1234567");
assert_eq!(jiter.array_step().unwrap(), Some(Peek::String));
// same again
assert_eq!(jiter.known_str().unwrap(), "+44 2345678");
// next we'll get `None` from `array_step` as the array is finished
assert_eq!(jiter.array_step().unwrap(), None);
// and `None` from `next_key` as the object is finished
assert_eq!(jiter.next_key().unwrap(), None);
// and we check there's nothing else in the input
jiter.finish().unwrap();
}There are lies, damned lies and benchmarks.
In particular, serde-json benchmarks use serde_json::Value which is significantly slower than deserializing
to a string.
For more details, see the benchmarks.
running 30 tests
test big_jiter_iter ... bench: 7,056,970 ns/iter (+/- 93,517)
test big_jiter_value ... bench: 7,928,879 ns/iter (+/- 150,790)
test big_serde_value ... bench: 32,281,154 ns/iter (+/- 1,152,593)
test bigints_array_jiter_iter ... bench: 26,579 ns/iter (+/- 833)
test bigints_array_jiter_value ... bench: 32,602 ns/iter (+/- 1,901)
test bigints_array_serde_value ... bench: 148,677 ns/iter (+/- 4,517)
test floats_array_jiter_iter ... bench: 36,071 ns/iter (+/- 2,448)
test floats_array_jiter_value ... bench: 33,926 ns/iter (+/- 25,554)
test floats_array_serde_value ... bench: 231,632 ns/iter (+/- 15,617)
test massive_ints_array_jiter_iter ... bench: 102,095 ns/iter (+/- 1,645)
test massive_ints_array_jiter_value ... bench: 108,109 ns/iter (+/- 8,396)
test massive_ints_array_serde_value ... bench: 517,150 ns/iter (+/- 53,110)
test medium_response_jiter_iter ... bench: 0 ns/iter (+/- 0)
test medium_response_jiter_value ... bench: 8,933 ns/iter (+/- 37)
test medium_response_serde_value ... bench: 10,074 ns/iter (+/- 454)
test pass1_jiter_iter ... bench: 0 ns/iter (+/- 0)
test pass1_jiter_value ... bench: 5,704 ns/iter (+/- 161)
test pass1_serde_value ... bench: 7,153 ns/iter (+/- 33)
test pass2_jiter_iter ... bench: 462 ns/iter (+/- 2)
test pass2_jiter_value ... bench: 1,448 ns/iter (+/- 14)
test pass2_serde_value ... bench: 1,385 ns/iter (+/- 13)
test string_array_jiter_iter ... bench: 1,112 ns/iter (+/- 26)
test string_array_jiter_value ... bench: 4,229 ns/iter (+/- 89)
test string_array_serde_value ... bench: 3,650 ns/iter (+/- 23)
test true_array_jiter_iter ... bench: 663 ns/iter (+/- 23)
test true_array_jiter_value ... bench: 1,239 ns/iter (+/- 80)
test true_array_serde_value ... bench: 1,307 ns/iter (+/- 75)
test true_object_jiter_iter ... bench: 3,205 ns/iter (+/- 177)
test true_object_jiter_value ... bench: 5,963 ns/iter (+/- 375)
test true_object_serde_value ... bench: 7,686 ns/iter (+/- 507)
test result: ok. 0 passed; 0 failed; 0 ignored; 30 measured
Running benches/python.rs (target/release/deps/python-11d488ef3a08ee17)
running 4 tests
test python_parse_medium_response ... bench: 8,397 ns/iter (+/- 183)
test python_parse_numeric ... bench: 427 ns/iter (+/- 8)
test python_parse_other ... bench: 160 ns/iter (+/- 8)
test python_parse_true_object ... bench: 8,817 ns/iter (+/- 102)
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