Readable.io API Example Code - VB.NET

ReadableApi.vb

'=====================================================================
' Readable.io REST Post Test
' --------------------------
' Basic asp.net (VB.Net) 4 page with textbox, label and submit button
' Created: 25 May 2018
' Author: humanotics.co.uk
'=====================================================================

Imports System.Net
Imports System.Security.Cryptography

Partial Class Readable
    Inherits System.Web.UI.Page

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 'submit button on page
        Dim strApiURL As Uri = New Uri("https://api.readable.io/api/text/")
        Dim strApiKey As String = "XXX" 'API key goes in here
        Dim lngRequestTime As Long = (DateTime.UtcNow - New DateTime(1970, 1, 1, 0, 0, 0)).TotalSeconds 'generate UNIX timestamp
        Dim apiSignature As String = GetHash(strApiKey & lngRequestTime.ToString) 'Hash the APIkey and Timestamp once concatenated

        Dim strText As String = TextBox1.Text 'get input from textbox on page
        Dim wReq As HttpWebRequest = WebRequest.Create(strApiURL) 'create a httpwebrequest object

        Dim postData As String = "text=" & strText 'generate post data
        Dim byteArray As Byte() = Encoding.UTF8.GetBytes(postData) 'convert postdata to byte array

        wReq.Method = "POST" 'Set POST method
        wReq.ContentType = "application/x-www-form-urlencoded" 'set FORM post type (not JSON)
        wReq.ContentLength = byteArray.Length 'set length of post request
        wReq.Headers.Add("API_SIGNATURE", apiSignature) 'set api signature http header
        wReq.Headers.Add("API_REQUEST_TIME", lngRequestTime.ToString) 'set api request time http header (UNIX timestamp)

        'convert request to datastream object
        Dim dataStream As IO.Stream = wReq.GetRequestStream()
        dataStream.Write(byteArray, 0, byteArray.Length)
        dataStream.Close()

        Dim response As WebResponse = wReq.GetResponse() 'declare response object
        dataStream = response.GetResponseStream() 'get response as datastream
        Dim reader As New IO.StreamReader(dataStream)
        Dim responseFromServer As String = reader.ReadToEnd() 'convert datastream to string

        'Output response from Readable.io to a label control on page
        Label1.Text = (responseFromServer)

        'Tidy up
        reader.Close()
        dataStream.Close()
        response.Close()
    End Sub
    
    Shared Function GetHash(theInput As String) As String
        'take the input string and generate a MD5 has of it
        Using hasher As MD5 = MD5.Create()
            Dim dbytes As Byte() =
                 hasher.ComputeHash(Encoding.UTF8.GetBytes(theInput))
            Dim sBuilder As New StringBuilder()
            For n As Integer = 0 To dbytes.Length - 1
                sBuilder.Append(dbytes(n).ToString("X2"))
            Next n
            Return sBuilder.ToString()
        End Using
    End Function
    
End Class