(DataFlex) 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 ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoJson
    Integer iSz
    Integer i
    Integer j
    Integer k
    Integer iSzI
    Integer iSzJ
    Integer iSzK
    Variant vObj2
    Handle hoObj2
    Variant vArr1
    Handle hoArr1
    Integer iSzArr1
    String sTemp1
    Integer iTemp1

    Move False To iSuccess

    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End
    Set ComEmitCompact Of hoJson To False

    // Assume the file contains the data as shown above..
    Get ComLoadFile Of hoJson "qa_data/json/pathSample.json" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoJson To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // First, let's get the value of "cc1"
    // The path to this value is: nestedObject.aaa.bb1.cc1
    Get ComStringOf Of hoJson "nestedObject.aaa.bb1.cc1" To sTemp1
    Showln sTemp1

    // Now let's get number 18 from the nestedArray.
    // It is located at nestedArray[1][2][1]
    // (remember: Indexing is 0-based)
    Get ComIntOf Of hoJson "nestedArray[1][2][1]" To iTemp1
    Showln "This should be 18: " iTemp1

    // 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.)
    Set ComI Of hoJson To 1
    Set ComJ Of hoJson To 2
    Set ComK Of hoJson To 1
    Get ComIntOf Of hoJson "nestedArray[i][j][k]" To iTemp1
    Showln "This should be 18: " iTemp1

    // Let's iterate over the array containing the numbers 17, 18, 19, 20.
    // First, use the SizeOfArray method to get the array size:
    Get ComSizeOfArray Of hoJson "nestedArray[1][2]" To iSz
    // The size should be 4.
    Showln "size of array = " iSz " (should equal 4)"

    // Now iterate...

    For i From 0 To (iSz - 1)
        Set ComI Of hoJson To i
        Get ComIntOf Of hoJson "nestedArray[1][2][i]" To iTemp1
        Showln iTemp1
    Loop

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

    // szI should equal 1.
    Get ComSizeOfArray Of hoJson "nestedArray" To iSzI
    For i From 0 To (iSzI - 1)
        Set ComI Of hoJson To i

        Get ComSizeOfArray Of hoJson "nestedArray[i]" To iSzJ
        For j From 0 To (iSzJ - 1)
            Set ComJ Of hoJson To j

            Get ComSizeOfArray Of hoJson "nestedArray[i][j]" To iSzK
            For k From 0 To (iSzK - 1)
                Set ComK Of hoJson To k

                Get ComIntOf Of hoJson "nestedArray[i][j][k]" To iTemp1
                Showln iTemp1
            Loop

        Loop

    Loop

    // 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"
    Get ComStringOf Of hoJson "mixture.arrayA[2].fruit" To sTemp1
    Showln sTemp1

    // This line of code gets the color "yellow"
    Get ComStringOf Of hoJson "mixture.arrayA[1].colors[0]" To sTemp1
    Showln sTemp1

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

    Get Create (RefClass(cComChilkatJsonObject)) To hoObj2
    If (Not(IsComObjectCreated(hoObj2))) Begin
        Send CreateComObject of hoObj2
    End
    Get pvComObject of hoObj2 to vObj2
    Get ComObjectOf2 Of hoJson "mixture.arrayA[1]" vObj2 To iSuccess

    // This object's "animal" should be "plankton"
    Get ComStringOf Of hoObj2 "animal" To sTemp1
    Showln sTemp1

    // Note that paths are relative to the object, not the absolute root of the JSON document.
    // Starting from obj2, "purple" is at "colors[2]"
    Get ComStringOf Of hoObj2 "colors[2]" To sTemp1
    Showln sTemp1

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

    Get Create (RefClass(cComChilkatJsonArray)) To hoArr1
    If (Not(IsComObjectCreated(hoArr1))) Begin
        Send CreateComObject of hoArr1
    End
    Get pvComObject of hoArr1 to vArr1
    Get ComArrayOf2 Of hoJson "mixture.arrayA[0].colors" vArr1 To iSuccess

    Get ComSize Of hoArr1 To iSzArr1
    For i From 0 To (iSzArr1 - 1)
        Get ComStringAt Of hoArr1 i To sTemp1
        Showln i ": " sTemp1
    Loop

    // The Chilkat JSON path uses ".", "[", and "]" chars for separators.  When a name
    // contains one of these chars, use double-quotes in the path:
    Get ComStringOf Of hoJson '"name.with.dots".grain' To sTemp1
    Showln sTemp1


End_Procedure