如何在C＃WCF中接收Stripe API Webhook

Question

I am trying to receive webhook from Stripe checkout post request. but Stripe document is only showing an example code of ASP.net whereas I am using WCF. https://stripe.com/docs/payments/checkout/fulfillment#webhooks

Here is the example request of Stripe checkout.

{
  "created": 1326853478,
  "livemode": false,
  "id": "evt_00000000000000",
  "type": "checkout.session.completed",
  "object": "event",
  "request": null,
  "pending_webhooks": 1,
  "api_version": "2019-05-16",
  "data": {
    "object": {
      "id": "cs_00000000000000",
      "object": "checkout.session",
      "billing_address_collection": null,
      "cancel_url": "https://example.com/cancel",
      "client_reference_id": null,
      "customer": null,
      "customer_email": null,
      "display_items": [
        {
          "amount": 1500,
          "currency": "usd",
          "custom": {
            "description": "Comfortable cotton t-shirt",
            "images": null,
            "name": "T-shirt"
          },
          "quantity": 2,
          "type": "custom"
        }
      ],
      "livemode": false,
      "locale": null,
      "payment_intent": "pi_00000000000000",
      "payment_method_types": [
        "card"
      ],
      "submit_type": null,
      "subscription": null,
      "success_url": "https://example.com/success"
    }
  }
}

at first I tried with class as a parameter.

[OperationContract]
[WebInvoke(Method = "POST",
BodyStyle = WebMessageBodyStyle.Wrapped,
ResponseFormat = WebMessageFormat.Json,
RequestFormat = WebMessageFormat.Json)]
void FromStripeCheckoutWrapped(Event data);

But all data were with null values. so, I tried to use my own Model classes according to the json request.

    public partial class Temperatures
    {
        [DataMember]
        public long Created { get; set; }
        [DataMember]
        public bool Livemode { get; set; }
        [DataMember]
        public string Id { get; set; }
        [DataMember]
        public string Type { get; set; }
        [DataMember]
        public string Object { get; set; }
        [DataMember]
        public object Request { get; set; }
        [DataMember]
        public long PendingWebhooks { get; set; }
        [DataMember]
        public string ApiVersion { get; set; }
        [DataMember]
        public Data Data { get; set; }
    } ...

But none of them received proper data.

The last thing I tried that receiving with String param like the question I found in stackoverflow but in Java. How to Receive Webhook from Stripe in Java He said he could print data in this way. but I couldn't.

The only way I made it succeed was typing every single params as written in the json request. I tried both and as too.

[OperationContract]
[WebInvoke(Method = "POST",
BodyStyle = WebMessageBodyStyle.Wrapped,
ResponseFormat = WebMessageFormat.Json,
RequestFormat = WebMessageFormat.Json)]
void FromStripeCheckoutWrapped(long created, bool livemode, string id ...);

Then I can get data properly..but it is too long to do everything like above. How can I receive POST request in an efficient and correct way? Please refer to the question in Java and Stripe webhook document as well.
I just want to read POST request as a String object regardless of the request structure, so that I can parse it.

Answer 1

I have no problem deserializing that example payload when I use the following DataContract classes:

[DataContract]
public class Base 
{
   [DataMember(Name="livemode")]
   public bool Livemode {get;set;}
   [DataMember(Name="object")]
   public string @Object {get;set;}
   [DataMember(Name="id")]
   public string Id {get;set;}
}

[DataContract]
public class Event:Base
{
   [DataMember(Name="created")]
   public long Created {get;set;}   
   [DataMember(Name="type")]
   public string Type {get;set;}
   [DataMember(Name="data")]
   public EventData Data {get;set;}
}

[DataContract]
public class EventData
{
   [DataMember(Name="object")]
   public EventObject EventObject {get;set;}
}

[DataContract]
public class EventObject:Base
{
   [DataMember(Name="display_items")]
   public Item[] DisplayItems {get;set;}
}

[DataContract]
public class Item
{
   [DataMember(Name="amount")]
   public double Amount {get;set;}
   [DataMember(Name="currency")]
   public string Currency {get;set;}
}

I use that DataContract in this Service Contract:

[ServiceContract]
interface IContract 
{
   [OperationContract]
   [WebInvoke(
        Method = "POST",
        BodyStyle = WebMessageBodyStyle.Bare,
        ResponseFormat = WebMessageFormat.Json,
        RequestFormat = WebMessageFormat.Json)]
   string StripeWebhook(Event data); 
}

When I create an implementation for that service:

public class JsonService:IContract 
{
  public  string StripeWebhook(Event data)
  {  
    data.Dump("rcvd data");
    return "{\"result\":\"success\"}";
  }
}

and feed that into a WebServiceHost:

// keeps the service running
AutoResetEvent are = new AutoResetEvent(false);

void Start() 
{
  //netsh http add urlacl url=http://+:8000/json user=USERNAME
  using (var serviceHost = new WebServiceHost(typeof(JsonService), new Uri("http://localhost:8000/json")))
  {
      serviceHost.AddServiceEndpoint(typeof(IContract), new WebHttpBinding(), "");
      serviceHost.Open();
      are.WaitOne(); // blocks 
      serviceHost.Close();
  }
}

I can call that service once I started it and POST the JSON to it:

void Main()
{
    new Thread(Start).Start();  
    try {
        var wc = new WebClient();
        wc.Headers.Add("content-type","application/json");
        wc.UploadString("http://localhost:8000/json/Stripewebhook", File.ReadAllText(@"example_json_wcf.json")).Dump("response");
    } catch(WebException e) {
       e.Dump("raw");
       using(var ms = new MemoryStream()) {
           e.Response.GetResponseStream().CopyTo(ms);
           Encoding.UTF8.GetString(ms.ToArray()).Dump("error");
       }
    }
    Console.WriteLine("Now Running. Enter key will stop the service.");
    Console.ReadLine();
    are.Set();
}

This is what my result looks like in LinqPad:

Keep in mind:

• Bare or Wrapped does matter
• In (de)serialization casing matters

If deserialization fails, try to serialize your object tree first and then compare that result with what you actually need.
Or use one of many JSON to POCO services, for example: http://json2csharp.com/ (I'm not affiliated with that service, it just happened to be the first that popped up in my Google Search)