Lianja

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
    }
}

Lianja

llSuccess = .F.

loJson = createobject("CkJsonObject")

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

llSuccess = loJson.Load(lcJsonStr)
if (llSuccess = .F.) then
    ? loJson.LastErrorText
    release loJson
    return
endif

// Get the "abc" object.
loAbcObj = createobject("CkJsonObject")
llSuccess = loJson.ObjectOf2("abc",loAbcObj)
if (llSuccess = .F.) then
    ? loJson.LastErrorText
    release loJson
    release loAbcObj
    return
endif

// Side note: The JSON of a sub-part of the document can be emitted from any JSON object:
loAbcObj.EmitCompact = .F.
? loAbcObj.Emit()

// Navigate to the "x" array
loXArray = createobject("CkJsonArray")
loAbcObj.ArrayOf2("x",loXArray)

// Navigate to the 2nd object contained within the array.  This contains members b1 and b2
loBObj = createobject("CkJsonObject")
loXArray.ObjectAt2(1,loBObj)

// Show that we're at "b1/b2".
// The value of "b1" should be "200"
? "b2 = " + str(loBObj.IntOf("b2"))

// Now go back to the JSON doc root:
loDocRoot = createobject("CkJsonObject")
loBObj.GetDocRoot2(loDocRoot)

// 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.
loDocRoot.EmitCompact = .F.
? loDocRoot.Emit()


release loJson
release loAbcObj
release loXArray
release loBObj
release loDocRoot