(Visual FoxPro) Modify Parts of JSON Document

Demonstrates how to modify parts of a JSON document. This example uses the following JSON document:

{
   "fruit": [
      	{
         "kind": "apple",
	 "count": 24,
	 "fresh": true,
	 "extraInfo": null,
	 "listA": [ "abc", 1, null, false ],
	 "objectB": { "animal" : "monkey" }
      	},
	{
         "kind": "pear",
	 "count": 18,
	 "fresh": false,
	 "extraInfo": null
	 "listA": [ "xyz", 24, null, true ],
	 "objectB": { "animal" : "lemur" }
	}
    ],
    "list" : [ "banana", 12, true, null, "orange", 12.5, { "ticker": "AAPL" }, [ 1, 2, 3, 4, 5 ] ],
    "alien" : true
}

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL loJson
LOCAL lnSuccess
LOCAL loListA
LOCAL lnBNull
LOCAL loTickerObj
LOCAL loAa
LOCAL loAFruit
LOCAL loAppleObj
LOCAL loPearObj

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJson = CreateObject('Chilkat.JsonObject')

* Load the JSON from a file.
lnSuccess = loJson.LoadFile("qa_data/json/modifySample.json")
IF (lnSuccess <> 1) THEN
    ? loJson.LastErrorText
    RELEASE loJson
    CANCEL
ENDIF

* This example will not check for errors (i.e. null / false / 0 return values)...

* Get the "list" array:
loListA = loJson.ArrayOf("list")

* Modify values in the list.

* Change banana to plantain
lnSuccess = loListA.SetStringAt(0,"plantain")

* Change 12 to 24
lnSuccess = loListA.SetIntAt(1,24)

* Change true to false
lnSuccess = loListA.SetBoolAt(2,0)

* Is the 3rd item null?
lnBNull = loListA.IsNullAt(3)

* Change "orange" to 32.
lnSuccess = loListA.SetIntAt(4,32)

* Change 12.5 to 31.2
lnSuccess = loListA.SetNumberAt(5,"31.2")

* Replace the { "ticker" : "AAPL" } object with { "ticker" : "GOOG" }
* Do this by deleting, then inserting a new object at the same location.
lnSuccess = loListA.DeleteAt(6)
lnSuccess = loListA.AddObjectAt(6)
loTickerObj = loListA.ObjectAt(6)
lnSuccess = loTickerObj.AddStringAt(-1,"ticker","GOOG")

RELEASE loTickerObj

* Replace "[ 1, 2, 3, 4, 5 ]" with "[ "apple", 22, true, null, 1080.25 ]"
lnSuccess = loListA.DeleteAt(7)
lnSuccess = loListA.AddArrayAt(7)
loAa = loListA.ArrayAt(7)
lnSuccess = loAa.AddStringAt(-1,"apple")
lnSuccess = loAa.AddIntAt(-1,22)
lnSuccess = loAa.AddBoolAt(-1,1)
lnSuccess = loAa.AddNullAt(-1)
lnSuccess = loAa.AddNumberAt(-1,"1080.25")
RELEASE loAa

RELEASE loListA

* Get the "fruit" array
loAFruit = loJson.ArrayAt(0)

* Get the 1st element:
loAppleObj = loAFruit.ObjectAt(0)

* Modify values by member name:
lnSuccess = loAppleObj.SetStringOf("fruit","fuji_apple")
lnSuccess = loAppleObj.SetIntOf("count",46)
lnSuccess = loAppleObj.SetBoolOf("fresh",0)
lnSuccess = loAppleObj.SetStringOf("extraInfo","developed by growers at the Tohoku Research Station in Fujisaki")

RELEASE loAppleObj

* Modify values by index:
loPearObj = loAFruit.ObjectAt(1)
lnSuccess = loPearObj.SetStringAt(0,"bartlett_pear")
lnSuccess = loPearObj.SetIntAt(1,12)
lnSuccess = loPearObj.SetBoolAt(2,0)
lnSuccess = loPearObj.SetStringAt(3,"harvested in late August to early September")
RELEASE loPearObj

RELEASE loAFruit

loJson.EmitCompact = 0
? loJson.Emit()

RELEASE loJson