Integrating PayPal in C#/.NET Solution using WSDL (SOAP)

Question

Environment : Visual Studio 2010 Professional .NET Framework 4 C#

Added Service Reference using the following WSDL : https://www.paypalobjects.com/wsdl/PayPalSvc.wsdl

Problem 1 : When compiled simply like this, get a bunch of errors from the Reference.cs file. Looks like namespace errors. It mentions that it cannot find the Service Reference Namespace in my project's Namespace. Therefore, I went into the Reference.cs file and whereever I got this error, I removed the project's namespace before the method names, and now it compiles.

Finally getting access to all classes. Created and populated DoDirectPaymentReq and CustomSecurityHeader objects with the required properties. Created an instance of PayPalAPIAAInterfaceClient class, which contains the method DoDirectPayment which takes in the arguments of type CustomSecurityHeader and DoDirectPaymentReq. Looks like this :

using (var client = new **PayPalAPIAAInterfaceClient**())
{
   var credentials = new CustomSecurityHeaderType
   {
      Credentials = new UserIdPasswordType
      {
         Username = "[email protected]",
         Password = "xxxxxxx",
         Signature = "jksadfuhasfweakjhasf"
      }
   };

   _doDirectPaymentResponseType = client.DoDirectPayment(ref credentials, _doDirectPaymentReq);
}

Problem 2 : After writing a TestMethod for the method which contains the above code, I get the error as follows :

System.InvalidOperationException: Could not find default endpoint element that references contract 'Paypal.PayPalAPIAAInterface' in the ServiceModel client configuration section. This might be because no configuration file was found for your application, or because no endpoint element matching this contract could be found in the client element.

at System.ServiceModel.Description.ConfigLoader.LoadChannelBehaviors(ServiceEndpoint serviceEndpoint, String configurationName)
at System.ServiceModel.ChannelFactory.ApplyConfiguration(String configurationName, Configuration configuration)
at System.ServiceModel.ChannelFactory.ApplyConfiguration(String configurationName)
at System.ServiceModel.ChannelFactory.InitializeEndpoint(String configurationName, EndpointAddress address)
at System.ServiceModel.ChannelFactory`1..ctor(String endpointConfigurationName, EndpointAddress remoteAddress)
at System.ServiceModel.EndpointTrait`1.CreateSimplexFactory()
at System.ServiceModel.ClientBase`1.CreateChannelFactoryRef(EndpointTrait`1 endpointTrait)
at System.ServiceModel.ClientBase`1.InitializeChannelFactoryRef()
at System.ServiceModel.ClientBase`1..ctor()
at PaymentEngine.Paypal.PayPalAPIAAInterfaceClient..ctor() in Reference.cs: line 30063

Therefore, so far I have not been able to make a successful transaction using PayPal SOAP protocol via using WSDL in C#.

I was under the impression that this is very simple. Simply Add Service Reference and utilize the Classes with their properties and methods created in the proxy from WSDL.

Where am I going wrong ?

Am I using the wrong WSDL ? I'd like to test against Sandbox first and then go Live.

If I am right with the WSDL, looks like the class PayPalAPIAAInterfaceClient doesn't know its endpoint, which I don't know if I am suppose to set manually or not since its already there in the WSDL definition at the end (check it out). I think the class itself should know which endpoint to call depending on whether I am using Signature or Certificate to populate CustomSecurityHeaderType.

But how does the PayPalAPIAAInterfaceClient class know whether I am trying to call into the Sandbox (testing) or it is a live transaction ?

PayPal used to have two different WSDLs for Sandbox and for Live. They can be found here : ->https://cms.paypal.com/us/cgi-bin/?cmd=_render-content&content_ID=developer/e_howto_api_soap_PayPalSOAPAPIArchitecture

After speaking to their support I was asked to use the following WSDL for both Sandbox and Live: ->https://www.paypalobjects.com/wsdl/PayPalSvc.wsdl

But how do I tell the PayPalAPIAAInterfaceClient class when it is suppose to perform Live or Sandbox tests. And also to which end point to use depending on my method of SOAP and Signature. The endpoints from PayPal are mentioned here :

https://cms.paypal.com/us/cgi-bin/?cmd=_render-content&content_ID=developer/howto_api_endpoints

HELP !

Answer 1

You have a few problems here, but none should be too painful to resolve. First of all, when I add a Service Reference to the WSDL you link at the top of your post I don't have any of the problems with namespaces that you describe. It could be that your own namespaces/references are conflicting somehow with the auto-generated terms, or perhaps that you selected some strange option during the add reference process? A delete-and-re-add might solve the problem, or I guess you can just ignore it since you've already worked around it. (It is kind of a hassle to edit auto-generated code, however, so you should plan on a fix eventually.)

To resolve the InvalidOperationException, you probably just need to specify one of the endpoints that Visual Studio has automatically added to your app.config file. You should have something like this in your config file:

<system.serviceModel>
  <client>
    <endpoint name="PayPalAPI" ... />
    <endpoint name="PayPalAPIAA" ... />
  </client>
</system.serviceModel>

You can pass the name of the endpoint you want to the constructor of the proxy class. There are other options to solve this problem, but just specifying an endpoint is easy and clean. (Note: if you don't have this section in your config file, then something went wrong during the Add Service Reference phase. Again I would just suggest resetting your project and re-adding the reference.)

Finally, you don't want to use a using block when you make use of the proxy class in spite of it being IDisposable. Basically, there's a design bug in WCF.