WordPress WooCommerce ASP.net API WebHookHandler: The WebHook request must contain an entity body formatted as HTML Form Data

Question

I am trying to create a WebHookHandler for Webhooks send from WordPress WooCommerce in ASP.NET C#.

I started with creating a ASP.NET C# Azure API App WebApplication Project and adding the relevant references (Microsoft.AspNet.WebHooks.Common, Microsoft.AspNet.WebHooks.Receivers, Microsoft.AspNet.WebHooks.Receivers.WordPress). Added the WebHookConfig, WordPressWebHookHandler and registered the WebHookConfig in the GlobalAsax.

I then published the application as an Azure App Service.

My WordPressWebHookHandler is still the default of the examples and looks like this:

public class WordPressWebHookHandler : WebHookHandler
{
    public override Task ExecuteAsync(string receiver, WebHookHandlerContext context)
    {
        // make sure we're only processing the intended type of hook
        if("WordPress".Equals(receiver, System.StringComparison.CurrentCultureIgnoreCase))
        {
            // todo: replace this placeholder functionality with your own code
            string action = context.Actions.First();
            JObject incoming = context.GetDataOrDefault<JObject>();
        }

        return Task.FromResult(true);
    }
}

When testing a User Creation WebHook in WooCommerce I can see the request in the log as below.

But unfortunately it is never received while debugging and I see below error.

I am thinking maybe I need a custom WebHook instead of the WordPress specific one as this is a WooCommerce Webhook. Or possibly it is handled wrong in the routing and ends up in another controller.

Any help is much appreciated.

Answer 1

I would like to make some additions to Svek's answer as I now got my Proof-of-concept completed and understand a bit more about the receivers.

His answer pointed me in the right direction, but needs a little addition.

WordpressWebHookReceiver Can take in Wordpress Webhooks of type HttpPost. This does not work with Woocommerce as Woocommerce sends Json Webhook messages and will fail the HttpPost validation which is build into the WordpressWebHookReceiver class.

CustomWebHookReceiver Can take in custom ASP.NET Webhooks. The custom ASP.NET webhooks have a specific partner for validation which includes but is not limited to the 'ms-signature'. Even adding the header will not suffice as the signature is also used in a different way from out of the box Woocommerce to encrypt the message. Basically coming to a point that you can't integrate Woocommerce with the CustomWebHookReceiver without changing the Webhook classes of Woocommerce.

GenericWebHookReceiver This is the receiver you want, which accepts basically a generic set of Json data and will be able to use the "code" query parameter to verify the secret which you can add in the web.config of your asp.net api application. I used this receiver to finish the Proof-of-concept and got both the signature validation as well as the deciphering of the message working right of the bat.

My basic class which I will start to build into a real solution can be viewed below and changes the JObject into a dynamic object in the methods I call from the class. As you can see I have two methods currently added, one for the customer create and one for the order create to call the respective methods which do an insert into Dynamics 365 (former CRM).

public class GenericJsonWebHookHandler : WebHookHandler
{
    public GenericJsonWebHookHandler()
    {
        this.Receiver = "genericjson";
    }

    public override Task ExecuteAsync(string generator, WebHookHandlerContext context)
    {
        var result = false;

        try
        {
            // Get JSON from WebHook
            var data = context.GetDataOrDefault<JObject>();

            if(context.Id != "crcu" && context.Id != "cror")
                return Task.FromResult(true);

            if (context.Id == "crcu")
            {
                result = WoocommerceCRMIntegrations.Entities.Contact.CreateContactInCRM(data);
            }
            else if (context.Id == "cror")
            {
                result = WoocommerceCRMIntegrations.Entities.Order.CreateOrderInCRM(data);
            }
        }
        catch (Exception ex)
        {
            result = false;
        }


        return Task.FromResult(result);
    }
}