DataFlex

Get the Root of a JSON Document

See more JSON Examples

Demonstrates how to get back to the JSON root object from anywhere in the JSON document. This example uses the following JSON document:

{
  "flower": "tulip",
  "abc":
    {
    "x": [
       { "a" : 1 },
       { "b1" : 100, "b2" : 200 },
       { "c" : 3 }
    ],
    "y": 200,
    "z": 200
    }
}

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoJson
    String sJsonStr
    Variant vAbcObj
    Handle hoAbcObj
    Variant vXArray
    Handle hoXArray
    Variant vBObj
    Handle hoBObj
    Variant vDocRoot
    Handle hoDocRoot
    String sTemp1
    Integer iTemp1

    Move False To iSuccess

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

    Move '{"flower": "tulip","abc":{"x": [{ "a" : 1 },{ "b1" : 100, "b2" : 200 },{ "c" : 3 }],"y": 200,"z": 200}}' To sJsonStr

    Get ComLoad Of hoJson sJsonStr To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoJson To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Get the "abc" object.
    Get Create (RefClass(cComChilkatJsonObject)) To hoAbcObj
    If (Not(IsComObjectCreated(hoAbcObj))) Begin
        Send CreateComObject of hoAbcObj
    End
    Get pvComObject of hoAbcObj to vAbcObj
    Get ComObjectOf2 Of hoJson "abc" vAbcObj To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoJson To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Side note: The JSON of a sub-part of the document can be emitted from any JSON object:
    Set ComEmitCompact Of hoAbcObj To False
    Get ComEmit Of hoAbcObj To sTemp1
    Showln sTemp1

    // Navigate to the "x" array
    Get Create (RefClass(cComChilkatJsonArray)) To hoXArray
    If (Not(IsComObjectCreated(hoXArray))) Begin
        Send CreateComObject of hoXArray
    End
    Get pvComObject of hoXArray to vXArray
    Get ComArrayOf2 Of hoAbcObj "x" vXArray To iSuccess

    // Navigate to the 2nd object contained within the array.  This contains members b1 and b2
    Get Create (RefClass(cComChilkatJsonObject)) To hoBObj
    If (Not(IsComObjectCreated(hoBObj))) Begin
        Send CreateComObject of hoBObj
    End
    Get pvComObject of hoBObj to vBObj
    Get ComObjectAt2 Of hoXArray 1 vBObj To iSuccess

    // Show that we're at "b1/b2".
    // The value of "b1" should be "200"
    Get ComIntOf Of hoBObj "b2" To iTemp1
    Showln "b2 = " iTemp1

    // Now go back to the JSON doc root:
    Get Create (RefClass(cComChilkatJsonObject)) To hoDocRoot
    If (Not(IsComObjectCreated(hoDocRoot))) Begin
        Send CreateComObject of hoDocRoot
    End
    Get pvComObject of hoDocRoot to vDocRoot
    Get ComGetDocRoot2 Of hoBObj vDocRoot To iSuccess

    // We'll skip the null check and assume it's non-null...

    // Pretty-print the JSON doc from the root to show that this is indeed the root.
    Set ComEmitCompact Of hoDocRoot To False
    Get ComEmit Of hoDocRoot To sTemp1
    Showln sTemp1


End_Procedure