Using Fiddler to debug AJAX in ASP.NET MVC

Error processing SSI file

Answers

  1. Diego

    • 2015/5/14

    Have you tried the Firebug extension for Firefox? It can show the Ajax request and response. I've used it with ASP.NET Ajax. Not sure about MVC Ajax.

  2. Rowan

    • 2016/10/3

    This tool helps you to test REST API / SOAP Web requests very easily. Run fiddler to start capturing web requests/response made by various client However not all web requests appear in fiddler unless client application 

  3. Angelo

    • 2018/4/26

    IE9 RC allows Fiddler to proxy traffic sent to localhost or 127.0.0.1 without additional steps on your part. You should never encounter the "Localhost traffic not captured" problem with Firefox. The FiddlerHook add-on for Firefox removes "localhost" from the "bypass proxy" list when Fiddler is in "Capturing" mode.

  4. Trey

    • 2015/11/11

    Run fiddler to start capturing web requests/response made by various client However not all web requests appear in fiddler unless client application How to Test API using Fiddler (Call REST API for without Postman).

  5. Bianco

    • 2019/9/25

    So it turns out that if you use this overload :

    using (Ajax.BeginForm(new AjaxOptions()
    

    you get this code generated (the code that 'breaks'):

    <form action="http://localhost:51234/aboutus/contact" method="post" 
    

    but if you do this and include the action name:

    using (Ajax.BeginForm("Contact", new AjaxOptions()
    

    you get this code generated :

    <form action="Contact" method="post" 
    

    So i'm fine with that for now, but would welcome any other solutions.

  6. Rey

    • 2021/8/8

    To start/stop capture go to File > Check/Uncheck [Capture Traffic] option. By default when you run Fiddler it behaves as default proxy server on your system. However not all web requests appear in fiddler unless client application using system Default Proxy. Start / Stop Fiddler Capture.

  7. Ahmad

    • 2021/5/22

    I have a console app that communicates with a number of 3rd party services via http. The original version of the app is developed for the .net 

  8. James

    • 2016/8/24

    This article describes how to configure an ASP.NET web site to use Fiddler as a proxy, and allow Fiddler to capture web service calls between 

  9. Leo

    • 2020/9/4

    You could write a HTTPModule which uses a response filter in order to manipulate the HTML output replacing all "localhost:51234" strings.

    The HttpResponse class has a very useful property:

    public Stream Filter {get; set;}
    

    MSDN provides a helpful description of this property:

    "Gets or sets a wrapping filter object used to modify the HTTP entity body before transmission."

    Here is a nice article which gives some background how you could do this: Implementing an IIS Application Filter Using .NET HttpModules and Response Filtering (page 3)

    As described in the object browser, the Filter gets or sets a wrapping filter object used to modify the HTTP entity body before transmission’. This is exactly what we need to do in order to make modifications to the HTML output of the HttpHandler. The Filter property is declared as type System.IO.Stream. In order to assign our own class to this filter property we need to define our class as inheriting from System.IO.Stream:

    public class PageFilter : System.IO.Stream
    

    We now have a Stream class, PageFilter, which can be assigned to the Response.Filter property. By attaching PageFilter to the Response.Filter property, PageFilter will be notified at critical times as data is written to the Response buffer. The most significant event of course is the Write operation. When this method is called, you’ll have the opportunity to modify data as it’s being written to the Response buffer. (I combine this with 'Response.Buffer = true' so that my PageFilter receives the complete response stream in a single method invocation.):

    public override void Write(byte[] buffer, int offset, int count)
    

    In the HttpModule, at the start of the request (I do it in OnBeginRequest) simply attach your HTTP response filter by assigning a new instance to Response.Filter:

    httpCtx.Response.Filter = 
       new PageFilter(httpCtx.Response.Filter)
    

    This other article shows a full working example implementation:

    http://aspnetresources.com/articles/HttpFilters.aspx

    I hope this helps!

  10. Hill

    • 2016/7/30

    Fiddler is an all-in-one HTTP traffic tracking tool that supports all types of applications. If you want to configure Android, Windows Phone, and iOS device to use Fiddler, check out Configuring Clients section here. It works on both client and server editions of Windows.

  11. Reese

    • 2015/1/8

    NET Core Web API projects, Console app projects and XUnit Test classes. I might be able to resolve this by pointing the code to the Fiddler 

  12. Villa

    • 2017/5/30

    Is there any configuration change I can make to monitor that outgoing /how-to-​capture-http-messages-from-request-node-library-with-fiddler 

  13. Wilson

    • 2021/10/15

    Can Fiddler capture localhost traffic?

  14. Kaysen

    • 2015/1/2

    Fiddler is an all-in-one HTTP traffic tracking tool that supports all types of applications. If you want to configure Android, Windows Phone, and iOS device to use Fiddler, check out Configuring Clients section here. It works on both client and server editions of Windows. Download Fiddler

  15. Jimmy

    • 2016/8/20

    How do you capture traffic in Fiddler?

  16. Jase

    • 2019/3/26

    Open Fiddler and select Tools -> Options. Choose the Connections tab. Select the Allow remote computers to connect checkbox to enable the setting. Restart Fiddler in order the changes to take effect.

  17. Yael

    • 2015/5/27

    Fiddler is a proxy server; on startup, it sets the Windows proxy configuration to point to itself. Applications that do not adopt the system proxy 

  18. Iker

    • 2018/9/1

    Capturing Traffic direct to application Launch Fiddler and stop traffic capture by unchecking 'Capture Traffic F12' under 'File' menu Launch browser Clear browser cache In Fiddler, click on 'Filters' tab in the right frame (details) section

  19. Jadiel

    • 2018/7/14

    Seems to be a trivial exercise, but I could not see the captured traffic in So you need to set the proxy settings in your local application that you 

  20. Michel

    • 2021/4/11

    said 12 days ago Fiddler Everywhere should set the proxy to manual (and by default set IP 127.0.0.1 with port 8866) only when Live Traffic Capturing mode is on. Pausing the live traffic should reset your OS proxy settings (this is expected) so that you could continue to use the default Internet connection.

  21. Price

    • 2017/6/9

    NET sandbox for developers to quickly try out code and share code snippets.

  22. Pellegrini

    • 2015/1/27

    Fiddler sees traffic by your user account. Since web services run by the application pool identity, fiddler cannot see their traffic. The easiest solution (and the only one that worked for me) is to change the website application pool user to run under your account. Simply: Open IIS

  23. Lian

    • 2020/2/16

    Download and install Fiddler Classic web debugging tool. Watch a quick tutorial to get started.

  24. Johnathan

    • 2017/7/10

    When Fiddler launches and attaches, it adjusts the current user’s proxy settings to point at Fiddler, running on 127.0.0.1:8888 by default. That means that traffic from most applications automatically flows through Fiddler without any additional configuration steps. However, sometimes you might want to capture traffic running in a different user account – for instance, you may want to capture web service calls from an ASP.NET page to a web service running on a different machine, or you

  25. Westley

    • 2020/1/3

    1. Downloading and Installing Fiddler. 1.1. Go to this link to install Fiddler. 1.2. Add Your email. Check the box to accept the 

  26. Cohen

    • 2020/12/16

    Download the full version of Fiddler. For web traffic capture only, download FiddlerCap. 2. Run the Fiddler Installer. a. Select 'Run' from any Security Warning dialog. b. Agree to the License Agreement. c. Select the install directory for Fiddler. d. Click 'Close' when installation completes. See Also: Configure your web browser to use Fiddler

  27. Briggs

    • 2021/5/27

    Let's take a close look at what Fiddler stands for today and how it can alleviate network stack pain for most developers. Fiddler Beginnings. The 

  28. Davis

    • 2019/1/16

    Capturing SOAP messages using Fiddler. 0. Unable to redirect https traffic from external IP to loopback interface in Fiddler. 0. Fiddler not seeing requests. 1.

  29. Moretti

    • 2019/7/27

    Is Fiddler safe to download?

  30. Orion

    • 2017/8/7

    Once installed, launch the application and proceed with the following: Disable capturing traffic using the File | Capture Traffic menu. Remove all sessions (select all items in the list, press the Delete key) Configure Fiddler to capture HTTPS traffic from the Tools | Fiddler Options menu. Open

  31. Francisco

    • 2020/4/15

    Fiddler not capturing api calls. Fiddler no longer capturing Web Service requests in .NET, It seems that WCF call are using WinHTTP, not WinINET. Fiddler is 

  32. Phillips

    • 2019/4/6

    Sameera, there are 2 major possibilities this to happen - either your WS calls does not go through Fiddler or they are filtered by Fiddler. The second one is easier to diagnose - go to Help -> Troubleshoot. This will disable all filters and will show all otherwise filtered traffic with striketrought font.

  33. Junior

    • 2018/9/21

    Fiddler captures localhost traffic just fine. The problem (SSL traffic not showing up in Fiddler for UWP apps) happens when I use Windows.

  34. Rory

    • 2020/2/1

    Configure a Java Application to Use Fiddler. To configure a Java application to send web traffic to Fiddler, set the proxy using jre: jre -DproxySet=true -Dhttp.proxyHost=127.0.0.1 -Dhttp.proxyPort=8888. Or: jre -DproxySet=true -DproxyHost=127.0.0.1 -DproxyPort=8888 MyApp. Or, change the Java Virtual Machine's proxy settings programmatically:

  35. Collin

    • 2018/10/18

    But, WS traffic is no longer captured in Fiddler. Anything else to It's just when the host application is on .net core, the problem occurs. Perhaps 

  36. Kase

    • 2019/4/25

    Once installed, launch the application and proceed with the following: Disable capturing traffic using the File | Capture Traffic menu. Remove all sessions (select all items in the list, press the Delete key) Configure Fiddler to capture HTTPS traffic from the Tools | Fiddler Options menu. Open

  37. Kenneth

    • 2015/1/12

    How To Use Fiddler With ASP.NET Web API Testing · Testing GET is very easy. · First, we need to click Composer tab on the Fiddler app. · Next, 

  38. Eric

    • 2018/3/8

    Configure Fiddler/ Tasks Capture Traffic from a Different Account To capture traffic from accounts other than the current user (for example, ASP.NET on IIS or a Windows Service), configure that process to use the Fiddler proxy.

  39. Knox

    • 2015/9/28

    Decrypting HTTPS traffic using Fiddler. Fiddler allows you to decrypt HTTPS traffic by installing its root certificate and enabling HTTPS decryption.

  40. Williams

    • 2020/7/27

    Select the Compose Tab, Then choose the HTTP verb as POST. Set the Content-Type as application/JSON. In the request body, provide the string value that you want to add into the string array. Click on the Execute button as shown below.

Comments are closed.

More Posts