(Unicode C) JSON Paths

Demonstrates using "Chilkat JSON Paths" to access parts of a JSON document, or to iterate over parts.

This example uses the following JSON document:

{
    "nestedArray" : [
			[
				[1,2,3],
				[4,5,6],
				[7,8,9,10]
			],
			[
				[11,12,13],
				[14,15,16],
				[17,18,19,20]
			],
			[
				[21,22,23],
				[24,25,26],
				[27,28,29,30],
				[31,32,33,34,35,36]
			]
		],

	"nestedObject" : {
		"aaa" : {
			"bb1" : {
				"cc1" : "c1Value",
				"cc2" : "c2Value",
				"cc3" : "c3Value"
			},
			"bb2" : {
				"dd1" : "d1Value",
				"dd2" : "d2Value",
				"dd3" : "d3Value"
			}
		}
	},

	"mixture" : {
		"arrayA" : [  
			{ "fruit": "apple", "animal": "horse", "job": "fireman", "colors": ["red","blue","green"] },
			{ "fruit": "pear", "animal": "plankton", "job": "waiter", "colors": ["yellow","orange","purple"] },
			{ "fruit": "kiwi", "animal": "echidna", "job": "astronaut", "colors": ["magenta","tan","pink"] }
			]
	},


        "name.with.dots" : { "grain" : "oats" }

	
}

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat C/C++ Library Downloads
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#include <C_CkJsonObjectW.h>
#include <C_CkJsonArrayW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkJsonObjectW json;
    int sz;
    int i;
    int j;
    int k;
    int szI;
    int szJ;
    int szK;
    HCkJsonObjectW obj2;
    HCkJsonArrayW arr1;
    int szArr1;

    success = FALSE;

    json = CkJsonObjectW_Create();
    CkJsonObjectW_putEmitCompact(json,FALSE);

    // Assume the file contains the data as shown above..
    success = CkJsonObjectW_LoadFile(json,L"qa_data/json/pathSample.json");
    if (success == FALSE) {
        wprintf(L"%s\n",CkJsonObjectW_lastErrorText(json));
        CkJsonObjectW_Dispose(json);
        return;
    }

    // First, let's get the value of "cc1"
    // The path to this value is: nestedObject.aaa.bb1.cc1
    wprintf(L"%s\n",CkJsonObjectW_stringOf(json,L"nestedObject.aaa.bb1.cc1"));

    // Now let's get number 18 from the nestedArray.
    // It is located at nestedArray[1][2][1]
    // (remember: Indexing is 0-based)
    wprintf(L"This should be 18: %d\n",CkJsonObjectW_IntOf(json,L"nestedArray[1][2][1]"));

    // We can do the same thing in a more roundabout way using the 
    // I, J, and K properties.  (The I,J,K properties will be convenient
    // for iterating over arrays, as we'll see later.)
    CkJsonObjectW_putI(json,1);
    CkJsonObjectW_putJ(json,2);
    CkJsonObjectW_putK(json,1);
    wprintf(L"This should be 18: %d\n",CkJsonObjectW_IntOf(json,L"nestedArray[i][j][k]"));

    // Let's iterate over the array containing the numbers 17, 18, 19, 20.
    // First, use the SizeOfArray method to get the array size:
    sz = CkJsonObjectW_SizeOfArray(json,L"nestedArray[1][2]");
    // The size should be 4.
    wprintf(L"size of array = %d (should equal 4)\n",sz);

    // Now iterate...

    for (i = 0; i <= sz - 1; i++) {
        CkJsonObjectW_putI(json,i);
        wprintf(L"%d\n",CkJsonObjectW_IntOf(json,L"nestedArray[1][2][i]"));
    }

    // Let's use a triple-nested loop to iterate over the nestedArray:

    // szI should equal 1.
    szI = CkJsonObjectW_SizeOfArray(json,L"nestedArray");
    for (i = 0; i <= szI - 1; i++) {
        CkJsonObjectW_putI(json,i);

        szJ = CkJsonObjectW_SizeOfArray(json,L"nestedArray[i]");
        for (j = 0; j <= szJ - 1; j++) {
            CkJsonObjectW_putJ(json,j);

            szK = CkJsonObjectW_SizeOfArray(json,L"nestedArray[i][j]");
            for (k = 0; k <= szK - 1; k++) {
                CkJsonObjectW_putK(json,k);

                wprintf(L"%d\n",CkJsonObjectW_IntOf(json,L"nestedArray[i][j][k]"));
            }

        }

    }

    // Now let's examine how to navigate to JSON objects contained within JSON arrays.
    // This line of code gets the value "kiwi" contained within "mixture"
    wprintf(L"%s\n",CkJsonObjectW_stringOf(json,L"mixture.arrayA[2].fruit"));

    // This line of code gets the color "yellow"
    wprintf(L"%s\n",CkJsonObjectW_stringOf(json,L"mixture.arrayA[1].colors[0]"));

    // Getting an object at a path:
    // This gets the 2nd object in "arrayA"

    obj2 = CkJsonObjectW_Create();
    CkJsonObjectW_ObjectOf2(json,L"mixture.arrayA[1]",obj2);

    // This object's "animal" should be "plankton"
    wprintf(L"%s\n",CkJsonObjectW_stringOf(obj2,L"animal"));

    // Note that paths are relative to the object, not the absolute root of the JSON document.
    // Starting from obj2, "purple" is at "colors[2]"
    wprintf(L"%s\n",CkJsonObjectW_stringOf(obj2,L"colors[2]"));

    // Getting an array at a path:
    // This gets the array containing the colors red, green, blue:

    arr1 = CkJsonArrayW_Create();
    CkJsonObjectW_ArrayOf2(json,L"mixture.arrayA[0].colors",arr1);

    szArr1 = CkJsonArrayW_getSize(arr1);
    for (i = 0; i <= szArr1 - 1; i++) {
        wprintf(L"%d: %s\n",i,CkJsonArrayW_stringAt(arr1,i));
    }

    // The Chilkat JSON path uses ".", "[", and "]" chars for separators.  When a name
    // contains one of these chars, use double-quotes in the path:
    wprintf(L"%s\n",CkJsonObjectW_stringOf(json,L"\"name.with.dots\".grain"));


    CkJsonObjectW_Dispose(json);
    CkJsonObjectW_Dispose(obj2);
    CkJsonArrayW_Dispose(arr1);

    }