Course info
Jun 18, 2012
2h 19m

Telerik's Fiddler is a very popular tracing tool for web traffic. It is very powerful but still extremely easy to use. Fiddler an invaluable tool for all web developers to review how a web site works, troubleshoot problems, and do performance evaluations. It is highly extensible using FiddlerScript or by creating .NET extensions. The customizations include additions to the Fiddler UI as well as automatically adjusting traffic before it is sent to the web server or before the response is sent to the client. The features can also be embedded into your own .NET application via FiddlerCore. The FiddlerCap utility provides an easy way for users or customers to capture web traces to identify problems. It is not limited to just Windows, as it can also be configured to capture traces for smartphones, tablets, and non-Windows platforms.

About the author
About the author

Robert is a Microsoft MVP, a Progress Developer Expert (Fiddler), and a 3rd degree black belt in Tae Kwon Do. He regularly speaks at national and international events.

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Section Introduction Transcripts
Section Introduction Transcripts

Hi. My name is Robert Boedigheimer. Welcome to Pluralsight's course on Fiddler. In this first module, we're going to review the HTTP Protocol used between web browsers and web surfers. We're going to see what a basic request and response look like. We're going to answer then the following questions, what is Fiddler? Why you use Fiddler? How does Fiddler work? Where to get Fiddler? And review some basic usage by showing a capture between a web browser and web server visiting a typical website.

Common Tasks
In this module, we'll talk about some of the common tasks we can use Fiddler for. The first one is just for a general site review. So, if I visit a web site and want a better understanding of how it works, what type of technologies does it use, Fiddler is a great way for me to get a view of how many requests are being made, what does it use, et cetera. It's also the main tool I'd like to start with for doing performance evaluations of a web site. So, there's a lot of things that we can see by doing a Fiddler trace to give us an idea about how the site performs and what areas we might want to focus on for making improvements. It's very helpful for troubleshooting problems, so it's very common for me when a web site is not working properly, I'll open up Fiddler to see if there's basic issues with 404s where files weren't deployed right, that the files aren't being downloaded correctly, et cetera. There's also a Composer or a Request Builder. So, this is the feature in Fiddler that allows me to make modifications to request before they go to the web server or to responses as they come back. Fiddler is very helpful for decrypting SSL Traffic. So in the past, if we wanted to get a trace between a browser and a server when it's using HTTPS, it was impossible to see what was actually contained within that traffic. Fiddler makes it easy for us to do that decryption so we can do the same task we'd normally use Fiddler for even when the traffic is encrypted. And the lastly, I want to review some common patterns that you'll see as you're using Fiddler for doing tracing, so that you're familiar with why is the traffic behaving the way that it is.

Fiddler Capabilities
In this module we're going to look at some of the other capabilities of Fiddler. We're going to compare it to browser tools. In this case, we're going to look at IE 9 Developer Tools just to give some perspective of how it differs and when one might be appropriate versus the other. We'll also compare it to a general network monitoring tool which in this case, we'll use Microsoft's Network Monitor. We'll look at filters and how we can use them to remove or hide or mark certain sessions that are found in the trace between the browser and the server. We're going to focus on the Web Sessions, so Fiddler calls an individual request and response, a Web Session. So we're going to look at the different things you can do to a Web Session and with a Web Session. We're going to look at breakpoints, so we can have Fiddler stop execution and wait at a particular point so that we can make modifications to the request or the response. We're going to look at Searches, how you can search within Fiddler for certain data coming back from the server or particular Web Sessions that match criteria. Really cool feature is the AutoResponder which is the capability to have Fiddler respond for you rather than the actual web server. So one for instance, is you could do a demo of your web server while being completely disconnected. So a Fiddler would actually act as the web server and return canned responses to the client. We'll see how to use Fiddler with other devices and platforms. We'll see how to trace. net services or web services or WCF traffic. And we'll also look at some common mistakes that you'll run into as you use Fiddler so that we can hopefully have you avoid them.

In this module, we're going to look at some of the more advanced features, or some of the features you won't use commonly, that we haven't seen before. The first is the QuickExec function. So this is an area on the bottom of Fiddler where you can type in quick actions and commands to hide things or select particular sessions, clear the list the sessions, set up break points, et cetera. We'll look at FiddlerScript, which is an easy way to extend how Fiddler runs using JScript. NET. We'll look at some of the popular Fiddler extensions that are available. We'll look at writing a Fiddler extension on your own, so if you want to create or extend the user interface or make changes automatically for changing requests or responses, that will be covered in writing a Fiddler extension. We'll look at FiddlerCore, which is taking the core functionality that Fiddler provides as far as capturing web sessions, being able to modify request responses, save archives. That's been pulled out into an assembly that you can embed in your own. NET applications. We'll look at FiddlerCap, which is a very simplified tool you can give to users and customers, so they can do a capture on their machine and then send it back so you can do full analysis within Fiddler. And then we'll touch on some miscellaneous topics around other uses of Fiddler. And then we'll wrap up with some good resources you can use to learn more information about Fiddler.