How can I trace oData request from a .Net DataServiceContext over SSL?

Question

I am developing a .Net client to retrieve data from an oData service. My client uses a System.Data.Services.Client.DataServiceContext.

I would like to see the actual oData requests sent out to the server. The server uses an SSL connection and requests to the server cannot easily be sniffed. I tried to do this with Burp. I added a SendingRequest EventHandler and set the Request.Proxy property. But this gives an exception:

The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.

Wireshark just shows the encrypted data.

Alternatively, I could contact the oData provider for server logs, but that would take some time. I am looking for a instantaneous trace.

---

Here is a sample client, that uses the Microsoft Northwind oData service.

1. Create a Class Library;
2. Add a Service Reference to Northwind;
3. Create a class oDataClient;
4. Add a method Customers();
5. Create a Test project;
6. Create in it a unit test for Customers();
7. Run the test.

Method:

public class oDataClient
{
    public void Customers()
    {
        {
            var context = new Northwind.NorthwindEntities(new System.Uri("http://services.odata.org/V3/Northwind/Northwind.svc/"));

            var customers = from c in context.Customers 
                            where c.CompanyName.StartsWith("A")
                            select c;

            int count = customers.Count();
        }
    }
}

Test:

[TestMethod()]
public void CustomersTest()
{
    oDataClient target = new oDataClient();
    target.Customers();
}

Answer 1

You can use the SendingRequest2, ReceivingResponse event to trace the out going OData request in client side. see the below example for more detail.

using Microsoft.OData.Client;
using Simple.OData.Client;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ODataClientApp
{
    class Program
    {
        private static string fileName = "TraceLog.log";
        private static Default.Container container;
        static void Main(string[] args)
        {
            try
            {
                var uri = "http://localhost:32097/odata";
                container = new Default.Container(new Uri(uri));

                container.SendingRequest2 += Container_SendingRequest2;
                container.ReceivingResponse += Container_ReceivingResponse;
                var moviles = container.Movies.Execute().ToList();
            }
            catch(Exception ex)
            {
                Console.WriteLine(ex.Message);
                Console.ReadLine();
            }
        }

        private static void Container_SendingRequest2(object sender, Microsoft.OData.Client.SendingRequest2EventArgs e)
        {
            var request = e.RequestMessage as HttpWebRequestMessage;
            var x = container;
            var url = request.Url.AbsoluteUri;
            var method = request.Method;
            var authenticationLevel = request.HttpWebRequest.AuthenticationLevel;
            var impersonationLevel = request.HttpWebRequest.ImpersonationLevel.ToString();
            var headers = request.Headers;
            var sb = new StringBuilder();
            sb.AppendLine(DateTime.Now.ToString() + "------------------------------SendingRequest2 Begin---------------------------");
            sb.AppendLine("Url:" + url);
            sb.AppendLine("Method:" + method);
            sb.AppendLine("Authentication Level:" + authenticationLevel);
            sb.AppendLine("Impersonation Level:" + impersonationLevel);
            sb.AppendLine();
            sb.AppendLine("Header Info:-");
            foreach (var header in headers)
            {
                sb.AppendFormat("{0}:{1}", header.Key, header.Value);
                sb.AppendLine();
            }
            sb.AppendLine(DateTime.Now.ToString() + "------------------------------SendingRequest2 End-----------------------------");
            File.AppendAllText(fileName, sb.ToString());
        }
        private static void Container_ReceivingResponse(object sender, Microsoft.OData.Client.ReceivingResponseEventArgs e)
        {
            var response = e.ResponseMessage as HttpWebResponseMessage;
            var statusCode = response.StatusCode.ToString();
            var headers = response.Headers;

            var sb = new StringBuilder();
            sb.AppendLine(DateTime.Now.ToString() + "------------------------------ReceivingResponse Begin-------------------------");
            sb.AppendLine("Status Code:" + statusCode);
            sb.AppendLine();
            sb.AppendLine("Header Info:-");
            foreach (var header in headers)
            {
                sb.AppendFormat("{0}:{1}", header.Key, header.Value);
                sb.AppendLine();
            }
            sb.AppendLine(DateTime.Now.ToString() + "------------------------------ReceivingResponse End---------------------------");
            File.AppendAllText(fileName, sb.ToString());
        }
    }
}