VB.NET Webhook Tutorial

This tutorial will take you through the ENTIRE process of creating a web hook receiver in VB and ASP.NET. It can be easily ported to C#, if you're not old like me.

It's safe to say that this tutorial does not exist anywhere on the internet. I've looked.

I'm going to code two of them in the next few days, this first one will receive a webhook sent from www.github.com, because it's easy, and easy to test repeatedly. I can just click a button on Github and it will send my webhook over and over.

The second one will be using the 'custom' API, it's going to come from a national bank.

Step one is included here, in the 'teaser' section, because many of you are not subscribers and I want you to know that I'm EASILY going to save you days of work here. I just spent 3 days figuring this out.

So...

Step 1:

Create a new ASP.NET Web Application (.NET Framework) (mine is in VB, but it can be easily ported to C#)

Step 2 is below.


VB.NET Webhook Tutorial

... and you 'll find more on the ApisAndWebhooks Menu

Empty.

Open the NuGet Package Manager

Add these

Make your project look like this. Add two classes (WebApiConfig and GitHubWebHookHandler) and Global.asax.

Add the Default page as a standard web page, and set it to 'set as default page'. This isn't really necessary, but it'll give the app a place to open to if you run it in the dev environment.

Web.config

Note: The code shown does not handle security, or this key, that's an additional complexity and we'll take that on later

<configuration>

<appSettings>

<add key="MS_WebHookReceiverSecret_GitHub" value="xxxxxxxxxxxx0c780e49a5c72972590571fd8" />

</appSettings>

<system.web>

Global.asax

Imports System.Web.Http

Imports System.Web.SessionState

Public Class Global_asax

Inherits System.Web.HttpApplication

Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)

'log the app opening

Dim logName = "Application"

Dim objEventLog As EventLog = New EventLog()

objEventLog.Source = logName

objEventLog.WriteEntry("global_asax", EventLogEntryType.Warning)

'this is a delegate, apparantly

System.Web.Http.GlobalConfiguration.Configure(AddressOf WebApiConfig.Register)

End Sub

End Class

WebApiConfig

Imports System

Imports System.IO

Imports System.Net

Imports System.Web

Imports System.Web.Http

Imports FPCommon

Module WebApiConfig

Sub Register(ByVal config As System.Web.Http.HttpConfiguration)

Dim strError As String = ""

Try

'this is called att app start from Global.asax

ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3

config.MapHttpAttributeRoutes()

config.Routes.MapHttpRoute(name:="DefaultApi", routeTemplate:="api/{controller}/{id}", defaults:=New With {Key .id = RouteParameter.[Optional]})

config.InitializeReceiveGitHubWebHooks()

Catch ex As Exception

ErrorHandler.globalErrorHandler(ex, strError, "vb", "sg", True)

End Try

End Sub

End Module

GitHubWebHookHandler

Imports System

Imports System.IO

Imports System.Net

Imports System.Threading.Tasks

Imports Microsoft.AspNet.WebHooks

Imports Newtonsoft.Json.Linq

Public Class GitHubWebHookHandler

Inherits WebHookHandler

Public Sub New()

Dim strError As String = ""

Try

Me.Receiver = Microsoft.AspNet.WebHooks.GitHubWebHookReceiver.ReceiverName

Dim strSubject As String = String.Format("GitHubWebHookHandler New {0:hh:mm:ss}", Now)

MailHandler.sendMail("credit@ngabrick.com", "steve@4penny.net", "", "", "webhook api notice", strSubject, MailHandler.ErrorHandlingTypeType.Ignore, "", "mail.ngabrick.com", False)

Catch ex As Exception

Throw ex

End Try

End Sub

Public Overrides Function ExecuteAsync(ByVal generator As String, ByVal context As WebHookHandlerContext) As Task

Dim strError As String = ""

Try

ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3

Dim entry As JObject = context.GetDataOrDefault(Of JObject)()

'"entry" is a JSON object, handle the incoming data here

Catch ex As Exception

Throw ex

End Try

Return Task.FromResult(True)

End Function

End Class

Now, go over to GitHub

Create a free account, if you need to

Add a repo, if you need to

Navigate to the repository

Click on Settings, then Webhooks

Fill this in as shown below. Your code needs to be public on the internet. It is possible to test without publishing to the internet... but that's a different article. Notice the 'secret' area. Github sends a 'secret' (they look like GUIDs) and the .NET app receives the secret and that way you know that someone is not spoofing you. This article does not handle the security, that's the next article.

You can set yourself up for as many notifications as you'd like, but it's quick and easy to set yourself up to receive 'stars'

This is the result. If you've coded all the above correctly, when you click the 'star' in Github you'll get the text below in the ExecuteAsync method. Find this line of code and handle the data. I didn't include it in the sample code because you won't want to do it my way. Recommend that you deserialize the JSON and then store it somehow in a database.

Dim entry As JObject = context.GetDataOrDefault(Of JObject)()

Resulting JSON

{

"action": "deleted",

"starred_at": null,

"repository": {

"id": 762457507,

"node_id": "R_kgDOLXItow",

"name": "Compare-Net-Objects",

"full_name": "sgray128/Compare-Net-Objects",

"private": false,

"owner": {