Get (Return) JSON data from Generic Handler from Code Behind using C# and VB.Net in ASP.Net

I have created it but how can i modify it to recieve response from API because the API sends data to URL which is suppossed to be recieved by the generic handler that iam supposed to create. my problem is modifying this generic handler to recieve this json data from the API so that because the API sends this Json data as a notification response to the URL upon completing a transaction successfully

<%@ WebHandler Language="VB" Class="Handler" %>
 
Imports System
Imports System.Web
 
Public Class Handler
    Inherits IHttpHandler
 
    Public Sub ProcessRequest(ByVal context As HttpContext)
        Dim name As String = context.Request.QueryString("name")
        Dim service As GetNameWithDate.WebService = New GetNameWithDate.WebService()
        Dim namewithTime As String = service.GetCurrentTime(name)
        context.Response.ContentType = "text/plain"
        context.Response.Write(namewithTime)
    End Sub
 
    Public Property IsReusable As Boolean
        Get
            Return False
        End Get
    End Property
End Class

but after talking to the API service provider this api sends this notification response as json in this format 

{"status": "SUCCESSFUL", "msisdn": "256782123456", "initiation_date": "2019-10-21 09:03:03","completion_date": "2019-10-21 09:03:22", "amount": 20000, "receipt_number":  "1587906379","reference_code": "c1a943f6-3f1aa162-95434a95-ef93f253-1aa43dc7"}

in your code these fields appears as parameter now how can this be properly coded so that the API service provider sends this Json out to this generic handler so that i can pick them from their.

Do you want to send the json response from API to generic handler?

Yes that is what i want

Hi makumbi,

Check this example. Now please take its reference and correct your code.

Here in the example i have hard coded the values to pass the json to handler. You need to get the json from the api.

Namespaces

C#

using System.Net;
using System.Web.Script.Serialization;

VB.Net

Imports System.Net
Imports System.Web.Script.Serialization

Code

C#

protected void Button1_Click(object sender, EventArgs e)
{
    Product product = new Product();
    product.status = "SUCCESSFUL";
    product.msisdn = "256782123456";
    product.initiation_date = Convert.ToDateTime("2019-10-21 09:03:03");
    product.completion_date = Convert.ToDateTime("2019-10-21 09:03:22");
    product.amount = 20000;
    product.receipt_number = "1587906379";
    product.reference_code = "c1a943f6-3f1aa162-95434a95-ef93f253-1aa43dc7";
    JavaScriptSerializer js = new JavaScriptSerializer();
    // Get the Json response from the api.
    string response = js.Serialize(product);
    string responseData = (new WebClient()).DownloadString("http://localhost:54496/Handler.ashx?Json=" + response);
    if (responseData != "")
    {
        MsgboxAsync("Hey!, Yr subscription IS BEING WORKED UPON THANK YOU", "Alright");
    }
}

public class Product
{
    public string status { get; set; }
    public string msisdn { get; set; }
    public DateTime initiation_date { get; set; }
    public DateTime completion_date { get; set; }
    public decimal amount { get; set; }
    public string receipt_number { get; set; }
    public string reference_code { get; set; }
}

VB.Net

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs)
    Dim product As Product = New Product()
    product.status = "SUCCESSFUL"
    product.msisdn = "256782123456"
    product.initiation_date = Convert.ToDateTime("2019-10-21 09:03:03")
    product.completion_date = Convert.ToDateTime("2019-10-21 09:03:22")
    product.amount = 20000
    product.receipt_number = "1587906379"
    product.reference_code = "c1a943f6-3f1aa162-95434a95-ef93f253-1aa43dc7"
    Dim js As JavaScriptSerializer = New JavaScriptSerializer()
    Dim response As String = js.Serialize(product)
    Dim responseData As String = (New WebClient()).DownloadString("http://localhost:54496/Handler.ashx?Json=" & response)
    If responseData <> "" Then
        MsgboxAsync("Hey!, Yr subscription IS BEING WORKED UPON THANK YOU", "Alright")
    End If
End Sub

Public Class Product
    Public Property status As String
    Public Property msisdn As String
    Public Property initiation_date As DateTime
    Public Property completion_date As DateTime
    Public Property amount As Decimal
    Public Property receipt_number As String
    Public Property reference_code As String
End Class

Generic Handler

C#

<%@ WebHandler Language="C#" Class="Handler" %>

using System;
using System.Web;
using System.Web.SessionState;
using System.Web.Script.Serialization;

public class Handler : IHttpHandler, IRequiresSessionState
{
    public void ProcessRequest(HttpContext context)
    {
        if (context.Request.QueryString["Json"] != null)
        {
            string json = context.Request.QueryString["Json"];
            JavaScriptSerializer js = new JavaScriptSerializer();
            Product product = js.Deserialize<Product>(json);

            string y = product.status;
            string w = product.reference_code;

            string output = "";
            if (y == "PENDING")
            {
                output = "Hey!, Yr subscription IS BEING WORKED UPON THANK YOU";
            }
            context.Response.ContentType = "text/plain";
            context.Response.Write(output);
        }
    }

    public bool IsReusable
    {
        get
        {
            return false;
        }
    }

    public class Product
    {
        public string status { get; set; }
        public string msisdn { get; set; }
        public DateTime initiation_date { get; set; }
        public DateTime completion_date { get; set; }
        public decimal amount { get; set; }
        public string receipt_number { get; set; }
        public string reference_code { get; set; }
    }
}

VB.Net

<%@ WebHandler Language="VB" Class="Handler" %>

Imports System
Imports System.Web
Imports System.Web.Script.Serialization

Public Class Handler : Implements IHttpHandler
    Public Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest
        If context.Request.QueryString("Json") IsNot Nothing Then
            Dim json As String = context.Request.QueryString("Json")
            Dim js As JavaScriptSerializer = New JavaScriptSerializer()
            Dim product As Product = js.Deserialize(Of Product)(json)
            Dim y As String = product.status
            Dim w As String = product.reference_code
            Dim output As String = ""
            If y = "PENDING" Then
                output = "Hey!, Yr subscription IS BEING WORKED UPON THANK YOU"
            End If
            context.Response.ContentType = "text/plain"
            context.Response.Write(output)
        End If
    End Sub

    Public ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
        Get
            Return False
        End Get
    End Property

    Public Class Product
        Public Property status As String
        Public Property msisdn As String
        Public Property initiation_date As DateTime
        Public Property completion_date As DateTime
        Public Property amount As Decimal
        Public Property receipt_number As String
        Public Property reference_code As String
    End Class
End Class