## What is Queryst?
[](https://travis-ci.org/rustless/queryst)
A query string parsing library for Rust inspired by https://github.com/hapijs/qs. A part of REST-like API micro-framework [Rustless].
```toml
# Cargo.toml
[dependencies.queryst]
git = "https://github.com/rustless/queryst"
```
[API docs](http://rustless.org/queryst/doc/queryst)
[Rustless]: https://github.com/rustless/rustless
## Usage
Use **queryst** library to parse query-string to corresponding [json] values.
```rust
use query::parse;
// will contain result as Json value
let object = parse("foo[0][a]=a&foo[0][b]=b&foo[1][a]=aa&foo[1][b]=bb");
```
You can work with raw Json value or decode it to Rust strucure by using serialize::json::decode function (see examples in [json]).
[json]: http://doc.rust-lang.org/serialize/json/index.html
## Description
**queryst** allows you to create nested objects within your query strings, by surrounding the name of sub-keys with square brackets `[]`. For example, the string `'foo[bar]=baz'` converts to this JSON:
```json
{
"foo": {
"bar": "baz"
}
}
```
URI encoded strings work too:
```js
parse('a%5Bb%5D=c');
// { "a": { "b": "c" } }
```
You can also nest your objects, like `'foo[bar][baz]=foobarbaz'`:
```javascript
{
"foo": {
"bar": {
"baz": "foobarbaz"
}
}
}
```
### Parsing Arrays
**queryst** can also parse arrays using a similar `[]` notation:
```javascript
parse('a[]=b&a[]=c');
// { "a": ["b", "c"] }
```
You may specify an index as well:
```javascript
parse('a[0]=c&a[1]=b');
// { "a": ["c", "b"] }
```
Note that the only difference between an index in an array and a key in an object is that the value between the brackets must be a number to create an array.
**queryst** **does't** allow to specify sparse indexes on arrays and will convert target array to object:
```javascript
parse('a[1]=b&a[15]=c');
// { "a": {"1":"b", "15":"c"} }
```
Also if you mix notations, **queryst** will merge the two items into an object:
```javascript
parse('a[0]=b&a[b]=c');
// { "a": { "0": "b", "b": "c" } }
```
You can also create arrays of objects:
```javascript
parse('a[][b]=c');
// { "a": [{ "b": "c" }] }
```