Skip to main content

Intercepting Core Service traffic with Fiddler

Fiddler2 is a proxy that runs locally on your machine and stays in-between a client (i.e. typically your browser) and the remote server. It can this way intercept the communication between the two and display it in various formats.

So, in order to intercept communication with the Core Service, one should configure their Core Service client application to use the Fiddler proxy. The proxy installs itself on your local machine (when Fiddler starts), and on port 8888.

Intercepted communication shows up in Fiddler somewhat like this:

So, how do I specify a proxy in my client application? That depends on the technology used.

Java Core Service Clients

There are several ways of doing this, but the idea is that we need to set two properties:
  • http.proxyHost - the host name or IP of the proxy server (i.e. localhost for Fiddler);
  • http.proxyPort - the port the proxy is listening to (i.e. 8888 for Fiddler);
If you have access to the code, you can set them using the System.setProperty method:

      // Fiddler proxy
      System.setProperty("http.proxyHost", "localhost");
      System.setProperty("http.proxyPort", "8888");

If you have access to the JVM, set the system properties in the startup sequence of the JVM (using the -D notation):

    java -Dhttp.proxyHost=localhost -Dhttp.proxyPort=8888 ...

.Net Core Service Clients

Fiddler installs itself as default proxy and .Net uses the default system proxy by default :) So there is nothing specific you need to setup for .Net.

The only caveat is that I couldn't get it to work -- namely, the basicHttp authentication fails when communication goes through the Fiddler proxy. The following error message shows up:

The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The authentication header received from the server was 'Negotiate,NTLM'.

However, I can see the authentication attempts are intercepted by Fiddler.

UPDATE: If I use wsHttp endpoint, the authentication negotiation is successful and Fiddler intercepts the communication correctly.


Comments

Popular posts from this blog

Running sp_updatestats on AWS RDS database

Part of the maintenance tasks that I perform on a MSSQL Content Manager database is to run stored procedure sp_updatestats . exec sp_updatestats However, that is not supported on an AWS RDS instance. The error message below indicates that only the sa  account can perform this: Msg 15247 , Level 16 , State 1 , Procedure sp_updatestats, Line 15 [Batch Start Line 0 ] User does not have permission to perform this action. Instead there are several posts that suggest using UPDATE STATISTICS instead: https://dba.stackexchange.com/questions/145982/sp-updatestats-vs-update-statistics I stumbled upon the following post from 2008 (!!!), https://social.msdn.microsoft.com/Forums/sqlserver/en-US/186e3db0-fe37-4c31-b017-8e7c24d19697/spupdatestats-fails-to-run-with-permission-error-under-dbopriveleged-user , which describes a way to wrap the call to sp_updatestats and execute it under a different user: create procedure dbo.sp_updstats with execute as 'dbo' as

Content Delivery Monitoring in AWS with CloudWatch

This post describes a way of monitoring a Tridion 9 combined Deployer by sending the health checks into a custom metric in CloudWatch in AWS. The same approach can also be used for other Content Delivery services. Once the metric is available in CloudWatch, we can create alarms in case the service errors out or becomes unresponsive. The overall architecture is as follows: Content Delivery service sends heartbeat (or exposes HTTP endpoint) for monitoring Monitoring Agent checks heartbeat (or HTTP health check) regularly and stores health state AWS lambda function: runs regularly reads the health state from Monitoring Agent pushes custom metrics into CloudWatch I am running the Deployer ( installation docs ) and Monitoring Agent ( installation docs ) on a t2.medium EC2 instance running CentOS on which I also installed the Systems Manager Agent (SSM Agent) ( installation docs ). In my case I have a combined Deployer that I want to monitor. This consists of an Endpoint and a

Debugging a Tridion 2011 Event System

OK, so you wrote your Tridion Event System. Now it's time to debug it. I know this is a hypothetical situtation -- your code never needs any kind of debugging ;) but indulge me... Recently, Alvin Reyes ( @nivlong ) blogged about being difficult to know how exactly to debug a Tridion Event System. More exactly, the question was " What process do I attach to for debugging even system code? ". Unfortunately, there is no simple or generic answer for it. Different events are fired by different Tridion CM modules. These modules run as different programs (or services) or run inside other programs (e.g. IIS). This means that you will need to monitor (or debug) different processes, based on which events your code handles. So the usual suspects are: dllhost.exe (or dllhost3g.exe ) - running as the MTSUser is the SDL Tridion Content Manager COM+ application and it fires events on generic TOM objects (e.g. events based on Tridion.ContentManager.Extensibility.Events.CrudEven