B4R Question Check if a string is valid Json

[peacemaker]

Hi, All
Any way to check like at "big brothers" https://www.b4x.com/android/forum/threads/check-if-a-string-is-valid-json-isjson.99974/ ?
GetTextValueFromKey sub may hang MCU up if with wrong JSON...

 

[peacemaker]

Now i guess, such sub maybe enough ?

Sub isJSON (JSON() As Byte) As Boolean
    If bc.StartsWith(JSON, "{".GetBytes) = False Then
        Return False
    End If
    If bc.LastIndexOf(JSON, "}".GetBytes) = -1 Then
        Return False
    End If
    Return True
End Sub

What think ?

 

[tchart]

Or this

May Be JSON (MayBeJSON)

B4X implementation of the "mayBeJSON" method from JSON Lib - https://github.com/jenkinsci/json-lib The method tests if the input String possibly represents a valid JSON String. This is handy as a check before running the JSONParser. Sub MayBeJSON(Input As String) As Boolean If Input.Length...

www.b4x.com

 

[peacemaker]

Or this

Thanks, updated: https://www.b4x.com/android/forum/threads/may-be-json-maybejson.129197/post-945690

 

[TILogistic]

test;

Public Sub IsValidJSON(sJson As String) As Boolean
    Try
        'Check format
        If sJson.Trim.Length = 0 Then Return False
        If sJson.Trim = Null Or sJson.Trim.ToLowerCase = "null" Then Return False
'        If sJson.Trim = "{}" Or sJson.Trim = "[]" Then Return False

        'Valid Format   
        Dim obj As Object
        If sJson.StartsWith("[") And sJson.EndsWith("]") Then obj = sJson.As(JSON).ToList
        If sJson.StartsWith("{") And sJson.EndsWith("}") Then obj = sJson.As(JSON).ToMap
        obj = obj.As(JSON).ToString
        Return True
    Catch
        Return False
    End Try
End Sub

Public Sub testJson
    Dim sJson As String = $"[{"Monday": 2, "Thursday": 5, "Friday": 6, "Sunday": 1, "Wednesday": 4, "Tuesday": 3, "Saturday": 7 }"$
    Log(IsValidJSON(sJson))
    Dim sJson As String = $"[{"Monday": 2, "Thursday": 5, "Friday": 6, "Sunday": 1, "Wednesday": 4, "Tuesday": 3, "Saturday": 7 }]"$
    Log(IsValidJSON(sJson))
    Dim sJson As String = $"{"Monday": 2, "Thursday": 5, "Friday": 6, "Sunday": 1, "Wednesday": 4, "Tuesday": 3, "Saturday": 7 }"$
    Log(IsValidJSON(sJson))
    Dim sJson As String = $"{}"$
    Log(IsValidJSON(sJson))
    Dim sJson As String = $"[]"$
    Log(IsValidJSON(sJson))
    Dim sJson As String = $"[dsdsdsd:]"$
    Log(IsValidJSON(sJson))
    Dim sJson As String = $"{dsdsd}"$
    Log(IsValidJSON(sJson))
    Dim sJson As String = $""$
    Log(IsValidJSON(sJson))
    Dim sJson As String = Null
    Log(IsValidJSON(sJson))
    Dim sJson As String = $"null"$
    Log(IsValidJSON(sJson))
End Sub