JSONByteArrayWriter problem?

Engineering 🇬🇧
ryusoup
2023-10-04
2026-06-14

  • ryusoup - 2023-10-04

    Hello,
    I am trying to implement a FB to make JSON formatted WSTRING type message using JSON Utilities 1.9.0.0 included in the IIoT library.

    In my case, I want to set some objects or arrays and set values to them later.
    But when I wrote as the sample below,

    // init builder
builder(pJsonData:=pJsonData, diRootObj=>diRootObj);

// set the 1st key to root
diKey1 := builder.SetKeyWithArray(wsKey:="key1", diParentIndex:=diRootObj, eError=>eError);

// set a value to the 1st key
wsValue:="value01";
builder.SetValue(Value:=wsValue, diParentIndex:=diKey1, eError=>eError);

// set the 2nd key to root
diKey2 := builder.SetKeyWithArray(wsKey:="key2", diParentIndex:=diRootObj, eError=>eError);

// set a value to the 2nd key
wsValue:="value02";
builder.SetValue(Value:=wsValue, diParentIndex:=diKey2, eError=>eError);

// set a value to the 1st key again
wsValue:="value03";
builder.SetValue(Value:=wsValue, diParentIndex:=diKey1, eError=>eError);

// set a value to the 2nd key again
wsValue:="value04";
builder.SetValue(Value:=wsValue, diParentIndex:=diKey2, eError=>eError);

// write build result
writer(xExecute:=TRUE, pwData:=ADR(wsResult), udiSize:=SIZEOF(wsResult), xAsyncMode:=FALSE, jsonData:=pJsonData^);

    the result was:

    {
   "key1": 
     ["value01"],
   "key2": 
     ["value02", "value03", "value04"]
}

    while my expection was:

    {
  "key1": 
    ["value01", "value03"],
  "key2": 
    ["value02", "value04"]
}

    Inspecting pJsonData^, JSONData itself seems to be ok, so I believe the issue is something caused by the writer FB.
    Does anyone know how to fix it?

    Thanks,

     

  • brouwyka - 2026-06-08

    Hey there! I am currently running into the exact same issue.
    The JsonData object has all inexes & parent indexes in the way I expect, everything is correctly "linked".
    It purely seems that the writer is incorrectly parsing said JsonData, not based on parent & child index, but on something else that breaks it and puts things at the root, instead of the specified parent index.

    Did you ever manage to find a solution, or another way of achieving your JSON composing?

    I'm currently working on Codesys V3.5 SP19 Patch 7 with IIOT Libraries SL 1.13.0.0, specifically JSON Utilities SL 1.13.0.0 (to send requests to APIs with JSON bodies using Web Client SL 1.13.0.0).

     

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