Json with parameters in Vb.net - json

Question

I need to send json data to an API including a QR code and some other values.
this is what i got from them
The needed parameter is:
• Parameter "data" in JSON:
id -> 100 (fixed, it is the ID needed for our software)
qrcode -> QRcode value
Example: data={"id":"100","qrcode":"VL11bbdb186a3a6dcfc57a1b07149c9a0e"}
and this is the code i use
Call:
Dim jsonPost As New JsonPost(postadress)
Dim dictqr As New Dictionary(Of String, Object)
dictqr.Add("id", lastmeas.id)
dictqr.Add("qrcode", lastmeas.qrcode)
jsonPost.PostData(dictqr)
and this is the definition
Public Class JsonPost
Private urlToPost As String = ""
Public Sub New(ByVal urlToPost As String)
Me.urlToPost = urlToPost
End Sub
Public Function PostData(ByVal dictData As Dictionary(Of String, Object)) As Boolean
Dim webClient As New WebClient()
Dim resByte As Byte()
Dim resString As String
Dim reqString() As Byte
ServicePointManager.ServerCertificateValidationCallback = Function(o, certificate, chain, errors) True
Try
webClient.Headers("content-type") = "application/json"
webClient.Headers("accept") = "*/*"
reqString = Encoding.Default.GetBytes(JsonConvert.SerializeObject(dictData, Newtonsoft.Json.Formatting.None))
resByte = webClient.UploadData(Me.urlToPost, "POST", reqString)
resString = Encoding.Default.GetString(resByte)
Form1.respuesta_envio = resString
webClient.Dispose()
Return True
Catch ex As Exception
Form1.respuesta_envio = ex.Message
CreateObject("WScript.Shell").Popup(ex.Message, 5, "Data not transfered")
End Try
Return False
End Function
End Class
if i deserialize, i get
{"id":"100","qrcode":"example"}
but i do not know how to include this data= part

Answer 1

The API appears to be asking you to send a JSON string inside a form-url-encoded parameter. That's unpleasant and not a logical way to design an API, but if that's what they require then that's what you'll have to do.
Therefore you need to:
remove the Content-Type header telling the server to expect a JSON body in the request. What you'll actually be sending is form-url-encoded data where the one parameter happens to contain JSON within its value. i.e. remove this line:
webClient.Headers("content-type") = "application/json"
prepend the data= bit to the JSON string generated by the SerializeObject function:
reqString = Encoding.Default.GetBytes("data=" & JsonConvert.SerializeObject(dictData, Newtonsoft.Json.Formatting.None))