crimaniak / json-pointer

JSON Pointer implementation

JavaScript Object Notation (JSON) Pointer

This is implementation of rfc6901.

JsonPointer for Json, like XPath for XML, used to locate part of document using format string.

library functionality:

• JsonPointer path parsing and verification
• element search in a document
• JsonPointer path component encoding

Json document format accepted: JSONValue

Interface

    struct JsonPointer
    {
    
    	/** 
    	 * Constructor. 
    	 * @throws Exception if error in path
    	 */
    	@safe this(string path);

       /// encode path component, quoting '~' and '/' symbols according to rfc6901
    	@safe static encodeComponent(string component) pure;
    	
    	// find element in given document according to path
    	Nullable!JSONValue evaluate(JSONValue root);
    	
    }

Usage examples

    import vision.json.pointer;
    import std.json;
    
    string s = `{ "language": "D", "rating": 3.5, "code": "42", "o": {"p1": 5, "p2": 6}, "a": [1,2,3,4,5] }`;
    JSONValue j = parseJSON(s);

    // tests for successful requests
    assert(JsonPointer("/language").evaluate(j).str == "D");
    assert(JsonPointer("/rating").evaluate(j).floating == 3.5);
    assert(JsonPointer("/o/p1").evaluate(j).integer == 5);
    assert(JsonPointer("/a/3").evaluate(j).integer == 4);
    
    // test encodeComponent
    assert(JsonPointer.encodeComponent("a/b~c") == "a~1b~0c");
    

json-pointer's Issues

GDC build failed

src/vision/json/pointer.d:5:12: error: module std.typecons import 'nullable' not found, did you mean struct 'Nullable(T)'?
import std.typecons : Nullable, nullable;
^
gdc failed with exit code 1.

LDC build failed

src/vision/json/pointer.d(17,16): Error: module std.algorithm import 'substitute' not found

gdc: module std.typecons import 'nullable' not found

Transfer evaluate() parameter and return value by reference to avoid node copying

std.json library uses struct for JSONValue so it need to work by reference to get node inside of document.

Add service functions isRoot, parent and lastComponent

json-patch package needs some additional functions

path /0 is not detected

Error in path tests for array case