jsonpath-lib

crates.io

Rust 버전 JsonPath 구현이다. Webassembly와 Javascript에서도 역시 동일한 API 인터페이스를 제공 한다.

It is an implementation of the Rust version [JsonPath] (https://goessner.net/articles/JsonPath/). Webassembly andJavascript also provide the same API interface.

Webassembly Demo

왜?

To enjoy Rust!

With Javascript

jsonpath-wasm library

(not yet published jsonpath-wasm) javascript // browser import * as jsonpath from "jsonpath-wasm"; // NodeJs const jsonpath = require('jsonpath-wasm');

jsonpath-rs library (Only NodeJS)

jsonpath-rs is native addon for NodeJs

(not yet published jsonpath-rs) javascript const jsonpath = require('jsonpath-rs');

javascript - jsonpath.select(json: string|object, jsonpath: string)

```javascript let jsonObj = { "school": { "friends": [{"id": 0}, {"id": 1}] }, "friends": [{"id": 0}, {"id": 1}] }; let ret = [{"id": 0}, {"id": 0}];

let a = jsonpath.select(JSON.stringify(jsonObj), "$..friends[0]"); let b = jsonpath.select(jsonObj, "$..friends[0]"); console.log( JSON.stringify(ret) == JSON.stringify(a), JSON.stringify(a) == JSON.stringify(b) ); ```

javascript - jsonpath.compile(jsonpath: string)

```javascript let template = jsonpath.compile("$..friends[0]");

let jsonObj = { "school": { "friends": [ {"id": 0}, {"id": 1} ] }, "friends": [ {"id": 0}, {"id": 1} ] };

let ret = JSON.stringify([ {"id": 0}, {"id": 0} ]);

// 1. read as json object console.log(JSON.stringify(template(jsonObj)) == ret); // 2. read as json string console.log(JSON.stringify(template(JSON.stringify(jsonObj))) == ret);

let jsonObj2 = { "school": { "friends": [ {"name": "Millicent Norman"}, {"name": "Vincent Cannon"} ] }, "friends": [ {"id": 0}, {"id": 1} ] };

let ret2 = JSON.stringify([ {"id": 0}, {"name": "Millicent Norman"} ]);

// 1. read as json object console.log(JSON.stringify(template(jsonObj2)) == ret2); // 2. read as json string console.log(JSON.stringify(template(JSON.stringify(jsonObj2))) == ret2); ```

javascript - jsonpath.selector(json: string|object)

```javascript let jsonObj = { "school": { "friends": [{"id": 0}, {"id": 1}] }, "friends": [{"id": 0},{"id": 1}] };

let ret1 = JSON.stringify([ {"id": 0}, {"id": 0} ]); let ret2 = JSON.stringify([ {"id": 1}, {"id": 1} ]);

// 1. read as json object let selector = jsonpath.selector(jsonObj); console.log(JSON.stringify(selector("$..friends[0]")) == ret1); console.log(JSON.stringify(selector("$..friends[1]")) == ret2);

// 2. read as json string let selector = jsonpath.selector(JSON.stringify(jsonObj)); console.log(JSON.stringify(selector("$..friends[0]")) == ret1); console.log(JSON.stringify(selector("$..friends[1]")) == ret2); ```

javascript - allocjson, deallocjson

(in jsonpath-rs not yet supported)

wasm-bindgen은 Javascript와 Webassembly 간 값을 주고받을 때 JSON 객체는 String으로 변환되기 때문에, 반복해서 사용되는 JSON 객체를 Webassembly 영역에 생성해 두면 성능에 도움이 된다.

Since wasm-bindgen converts JSON objects to String when exchanging values between Javascript and Webassembly, it is helpful to create repeated Json objects in Webassembly area.

```javascript

let jsonObj = { "school": { "friends": [{"id": 0}, {"id": 1}] }, "friends": [{"id": 0},{"id": 1}] };

let path = '$..friends[0]'; let template = jsonpath.compile(path); let selector = jsonpath.selector(jsonObj);

let ptr = jsonpath.alloc_json(jsonObj); if(ptr == 0) console.error('invalid ptr'); // 0 is invalid pointer let selector2 = jsonpath.selector(ptr);

let ret1 = selector(path) let ret2 = selector2(path) let ret3 = template(jsonObj); let ret4 = template(ptr); let ret5 = jsonpath.select(jsonObj, path); let ret6 = jsonpath.select(ptr, path);

console.log( JSON.stringify(ret1) == JSON.stringify(ret2),// true JSON.stringify(ret1) == JSON.stringify(ret3),// true JSON.stringify(ret1) == JSON.stringify(ret4),// true JSON.stringify(ret1) == JSON.stringify(ret5),// true JSON.stringify(ret1) == JSON.stringify(ret6));// true

jsonpath.dealloc_json(ptr);

```

With Rust (as library)

jsonpath_lib library

```rust extern crate jsonpath_lib as jsonpath;

[macro_use]

extern crate serde_json; ```

rust - jsonpath::select(json: &serde_json::value::Value, jsonpath: &str)

rust let json_obj = json!({ "school": { "friends": [{"id": 0}, {"id": 1}] }, "friends": [{"id": 0}, {"id": 1}] }); let json = jsonpath::select(json_obj, "$..friends[0]").unwrap(); let ret = json!([ {"id": 0}, {"id": 0} ]); assert_eq!(json, ret)

rust - jsonpath::select_str(json: &str, jsonpath: &str)

rust let json_obj = json!({ "school": { "friends": [{"id": 0}, {"id": 1}] }, "friends": [{"id": 0}, {"id": 1}] }); let json_str = jsonpath::select_str(&serde_json::to_string(&json_obj).unwrap(), "$..friends[0]").unwrap(); let json: Value = serde_json::from_str(&json_str).unwrap(); let ret = json!([ {"id": 0}, {"id": 0} ]); assert_eq!(json, ret)

rust - jsonpath::compile(jsonpath: &str)

```rust let mut template = jsonpath::compile("$..friends[0]");

let json_obj = json!({ "school": { "friends": [ {"id": 0}, {"id": 1} ] }, "friends": [ {"id": 0}, {"id": 1} ] });

let json = template(&jsonobj).unwrap(); let ret = json!([ {"id": 0}, {"id": 0} ]); asserteq!(json, ret);

let json_obj = json!({ "school": { "friends": [ {"name": "Millicent Norman"}, {"name": "Vincent Cannon"} ] }, "friends": [ {"id": 0}, {"id": 1} ] });

let json = template(jsonobj).unwrap(); let ret = json!([ {"id": 0}, {"name": "Millicent Norman"} ]); asserteq!(json, ret); ```

rust - jsonpath::selector(&json: serde_json::value::Value)

```rust let json_obj = json!({ "school": { "friends": [{"id": 0}, {"id": 1}] }, "friends": [{"id": 0},{"id": 1}] });

let mut selector = jsonpath::selector(&json_obj);

let json = selector("$..friends[0]").unwrap(); let ret = json!([ {"id": 0}, {"id": 0} ]); assert_eq!(json, ret);

let json = selector("$..friends[1]").unwrap(); let ret = json!([ {"id": 1}, {"id": 1} ]); assert_eq!(json, ret); ```