Imports System.IO
Imports System.Net
Imports Newtonsoft.Json
Imports Newtonsoft.Json.Linq

Module Module1

    ' The authentication key (API Key).
    ' Get your own by registering at https://app.pdf.co
    Const API_KEY As String = "***********************************"

    ' Result file name
    Const ResultFileName As String = ".\barcode.png"
    ' Barcode type. See valid barcode types in the documentation https://apidocs.pdf.co
    Const BarcodeType As String = "Code128"
    ' Barcode value
    Const BarcodeValue As String = "qweasd123456"

    Sub Main()

        ' Create standard .NET web client instance
        Dim webClient As WebClient = New WebClient()

        ' Set API Key
        webClient.Headers.Add("x-api-key", API_KEY)

        ' Set JSON content type
        webClient.Headers.Add("Content-Type", "application/json")

        ' Prepare URL for `Barcode Generator` API call
        Dim url As String = "https://api.pdf.co/v1/barcode/generate"

        ' Prepare requests params as JSON
        ' See documentation: https : //apidocs.pdf.co
        Dim parameters As New Dictionary(Of String, Object)
        parameters.Add("name", Path.GetFileName(ResultFileName))
        parameters.Add("type", BarcodeType)
        parameters.Add("value", BarcodeValue)

        ' Convert dictionary of params to JSON
        Dim jsonPayload As String = JsonConvert.SerializeObject(parameters)

        Try
            ' Execute POST request with JSON payload
            Dim response As String = webClient.UploadString(url, jsonPayload)

            ' Parse JSON response
            Dim json As JObject = JObject.Parse(response)

            If json("error").ToObject(Of Boolean) = False Then

                ' Get URL of generated barcode image file
                Dim resultFileURI As string = json("url").ToString()

                ' Download the image file
                webClient.DownloadFile(resultFileURI, ResultFileName)

                Console.WriteLine("Generated barcode saved to ""{0}"" file.", ResultFileName)

            Else 
                Console.WriteLine(json("message").ToString())
            End If

        Catch ex As WebException
            Console.WriteLine(ex.ToString())
        End Try

        webClient.Dispose()


        Console.WriteLine()
        Console.WriteLine("Press any key...")
        Console.ReadKey()

    End Sub

End Module