# json-pointer

A crate for parsing and using JSON pointers, as specified in [RFC
6901](https://tools.ietf.org/html/rfc6901). Unlike the `pointer` method
built into `serde_json`, this handles both validating JSON Pointers before
use and the URI Fragment Identifier Representation.

[![pipeline status](https://gitlab.com/jmap-rs/json-pointer/badges/master/pipeline.svg)](https://gitlab.com/jmap-rs/json-pointer/-/commits/master)
[![crates.io](https://img.shields.io/crates/v/json-pointer.svg)](https://crates.io/crates/json-pointer)
[![Documentation](https://docs.rs/json-pointer/badge.svg)](https://docs.rs/json-pointer)

## Creating a JSON Pointer

JSON pointers can be created with a literal `[&str]`, or parsed from a `String`.

```rust
let from_strs = JsonPointer::new([
    "foo",
    "bar",
]);
let parsed = "/foo/bar".parse::<JsonPointer<_, _>>().unwrap();

assert_eq!(from_strs.to_string(), parsed.to_string());
}
```

## Using a JSON Pointer

The `JsonPointer` type provides `.get()` and `.get_mut()`, to get references
and mutable references to the appropriate value, respectively.

```rust
let ptr = "/foo/bar".parse::<JsonPointer<_, _>>().unwrap();

let document = json!({
    "foo": {
        "bar": 0,
        "baz": 1,
    },
    "quux": "xyzzy"
});

let indexed = ptr.get(&document).unwrap();

assert_eq!(indexed, &json!(0));
```

## URI Fragment Identifier Representation

JSON Pointers can be embedded in the fragment portion of a URI. This is the
reason why most JSON pointer libraries require a `#` character at the beginning
of a JSON pointer. The crate will detect the leading `#` as an indicator to
parse in URI Fragment Identifier Representation. Note that this means that this
crate does not support parsing full URIs.

```rust
let str_ptr = "/f%o".parse::<JsonPointer<_, _>>().unwrap();
let uri_ptr = "#/f%25o".parse::<JsonPointer<_, _>>().unwrap();

assert_eq!(str_ptr, uri_ptr);
```